<s>
A	O
geographic	B-Application
information	I-Application
system	I-Application
(	O
GIS	B-Application
)	O
consists	O
of	O
integrated	O
computer	B-Architecture
hardware	I-Architecture
and	O
software	B-Application
that	O
store	O
,	O
manage	O
,	O
analyze	O
,	O
edit	O
,	O
output	O
,	O
and	O
visualize	O
geographic	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Much	O
of	O
this	O
often	O
happens	O
within	O
a	O
spatial	B-Algorithm
database	I-Algorithm
,	O
however	O
,	O
this	O
is	O
not	O
essential	O
to	O
meet	O
the	O
definition	O
of	O
a	O
GIS	B-Application
.	O
</s>
<s>
The	O
uncounted	O
plural	O
,	O
geographic	B-Application
information	I-Application
systems	I-Application
,	O
also	O
abbreviated	O
GIS	B-Application
,	O
is	O
the	O
most	O
common	O
term	O
for	O
the	O
industry	O
and	O
profession	O
concerned	O
with	O
these	O
systems	O
.	O
</s>
<s>
It	O
is	O
roughly	O
synonymous	O
with	O
geoinformatics	O
and	O
part	O
of	O
the	O
broader	O
geospatial	B-General_Concept
field	O
,	O
which	O
also	O
includes	O
GPS	O
,	O
remote	B-Application
sensing	I-Application
,	O
etc	O
.	O
</s>
<s>
Geographic	B-General_Concept
information	I-General_Concept
science	O
,	O
the	O
academic	O
discipline	O
that	O
studies	O
these	O
systems	O
and	O
their	O
underlying	O
geographic	O
principles	O
,	O
may	O
also	O
be	O
abbreviated	O
as	O
GIS	B-Application
,	O
but	O
the	O
unambiguous	O
GIScience	O
is	O
more	O
common	O
.	O
</s>
<s>
Geographic	B-Application
information	I-Application
systems	I-Application
are	O
utilized	O
in	O
multiple	O
technologies	O
,	O
processes	O
,	O
techniques	O
and	O
methods	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
GIS	B-Application
and	O
location	O
intelligence	O
applications	O
are	O
at	O
the	O
foundation	O
of	O
location-enabled	O
services	O
,	O
which	O
rely	O
on	O
geographic	O
analysis	O
and	O
visualization	O
.	O
</s>
<s>
GIS	B-Application
provides	O
the	O
capability	O
to	O
relate	O
previously	O
unrelated	O
information	O
,	O
through	O
the	O
use	O
of	O
location	O
as	O
the	O
"	O
key	O
index	O
variable	O
"	O
.	O
</s>
<s>
Locations	O
and	O
extents	O
that	O
are	O
found	O
in	O
the	O
Earth	O
's	O
spacetime	B-Protocol
are	O
able	O
to	O
be	O
recorded	O
through	O
the	O
date	O
and	O
time	O
of	O
occurrence	O
,	O
along	O
with	O
x	O
,	O
y	O
,	O
and	O
z	O
coordinates	O
;	O
representing	O
,	O
longitude	O
(	O
x	O
)	O
,	O
latitude	O
(	O
y	O
)	O
,	O
and	O
elevation	O
(	O
z	O
)	O
.	O
</s>
<s>
This	O
key	O
characteristic	O
of	O
GIS	B-Application
has	O
begun	O
to	O
open	O
new	O
avenues	O
of	O
scientific	O
inquiry	O
and	O
studies	O
.	O
</s>
<s>
While	O
digital	O
GIS	B-Application
dates	O
to	O
the	O
mid-1960s	O
,	O
when	O
Roger	O
Tomlinson	O
first	O
coined	O
the	O
phrase	O
"	O
geographic	B-Application
information	I-Application
system	I-Application
"	O
,	O
many	O
of	O
the	O
geographic	O
concepts	O
and	O
methods	O
that	O
GIS	B-Application
automates	O
date	O
back	O
decades	O
earlier	O
.	O
</s>
<s>
While	O
the	O
use	O
of	O
layers	O
much	O
later	O
became	O
one	O
of	O
the	O
typical	O
features	O
of	O
a	O
contemporary	O
GIS	B-Application
,	O
the	O
photographic	O
process	O
just	O
described	O
is	O
not	O
considered	O
a	O
GIS	B-Application
in	O
itself-	O
–	O
as	O
the	O
maps	O
were	O
just	O
images	O
with	O
no	O
database	O
to	O
link	O
them	O
to	O
.	O
</s>
<s>
Two	O
additional	O
developments	O
are	O
notable	O
in	O
the	O
early	O
days	O
of	O
GIS	B-Application
:	O
Ian	O
McHarg	O
's	O
publication	O
"	O
Design	O
with	O
Nature	O
"	O
and	O
its	O
map	O
overlay	B-Application
method	O
and	O
the	O
introduction	O
of	O
a	O
street	O
network	O
into	O
the	O
U.S.	O
Census	O
Bureau	O
's	O
DIME	O
(	O
Dual	O
Independent	O
Map	O
Encoding	O
)	O
system	O
.	O
</s>
<s>
Further	O
computer	B-Architecture
hardware	I-Architecture
development	O
spurred	O
by	O
nuclear	O
weapon	O
research	O
led	O
to	O
more	O
widespread	O
general-purpose	O
computer	O
"	O
mapping	O
"	O
applications	O
by	O
the	O
early	O
1960s	O
.	O
</s>
<s>
In	O
1960	O
the	O
world	O
's	O
first	O
true	O
operational	O
GIS	B-Application
was	O
developed	O
in	O
Ottawa	O
,	O
Ontario	O
,	O
Canada	O
,	O
by	O
the	O
federal	O
Department	O
of	O
Forestry	O
and	O
Rural	O
Development	O
.	O
</s>
<s>
Developed	O
by	O
Dr.	O
Roger	O
Tomlinson	O
,	O
it	O
was	O
called	O
the	O
Canada	O
Geographic	B-Application
Information	I-Application
System	I-Application
(	O
CGIS	O
)	O
and	O
was	O
used	O
to	O
store	O
,	O
analyze	O
,	O
and	O
manipulate	O
data	O
collected	O
for	O
the	O
Canada	O
Land	O
Inventory	O
,	O
an	O
effort	O
to	O
determine	O
the	O
land	O
capability	O
for	O
rural	O
Canada	O
by	O
mapping	O
information	O
about	O
soils	O
,	O
agriculture	O
,	O
recreation	O
,	O
wildlife	O
,	O
waterfowl	O
,	O
forestry	O
and	O
land	O
use	O
at	O
a	O
scale	O
of	O
1:50	O
,	O
000	O
.	O
</s>
<s>
CGIS	O
was	O
an	O
improvement	O
over	O
"	O
computer	O
mapping	O
"	O
applications	O
as	O
it	O
provided	O
capabilities	O
for	O
data	O
storage	O
,	O
overlay	B-Application
,	O
measurement	O
,	O
and	O
digitizing/scanning	O
.	O
</s>
<s>
It	O
supported	O
a	O
national	O
coordinate	O
system	O
that	O
spanned	O
the	O
continent	O
,	O
coded	O
lines	O
as	O
arcs	O
having	O
a	O
true	O
embedded	O
topology	B-Architecture
and	O
it	O
stored	O
the	O
attribute	O
and	O
locational	O
information	O
in	O
separate	O
files	O
.	O
</s>
<s>
As	O
a	O
result	O
of	O
this	O
,	O
Tomlinson	O
has	O
become	O
known	O
as	O
the	O
"	O
father	O
of	O
GIS	B-Application
"	O
,	O
particularly	O
for	O
his	O
use	O
of	O
overlays	B-Application
in	O
promoting	O
the	O
spatial	O
analysis	O
of	O
convergent	O
geographic	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
It	O
was	O
developed	O
as	O
a	O
mainframe-based	O
system	O
in	O
support	O
of	O
federal	O
and	O
provincial	O
resource	O
planning	O
and	O
management	O
.	O
</s>
<s>
Its	O
strength	O
was	O
continent-wide	O
analysis	O
of	O
complex	O
datasets	B-General_Concept
.	O
</s>
<s>
In1964	O
Howard	O
T	O
.	O
Fisher	O
formed	O
the	O
Laboratory	O
for	O
Computer	O
Graphics	O
and	O
Spatial	O
Analysis	O
at	O
the	O
Harvard	O
Graduate	O
School	O
of	O
Design	O
(	O
LCGSA	O
1965	O
–	O
1991	O
)	O
,	O
where	O
a	O
number	O
of	O
important	O
theoretical	O
concepts	O
in	O
spatial	B-General_Concept
data	I-General_Concept
handling	O
were	O
developed	O
,	O
and	O
which	O
by	O
the	O
1970s	O
had	O
distributed	O
seminal	O
software	B-Application
code	O
and	O
systems	O
,	O
such	O
as	O
SYMAP	O
,	O
GRID	O
,	O
and	O
ODYSSEY	O
,	O
to	O
universities	O
,	O
research	O
centers	O
and	O
corporations	O
worldwide	O
.	O
</s>
<s>
These	O
programs	O
were	O
the	O
first	O
examples	O
of	O
general	O
purpose	O
GIS	B-Application
software	I-Application
that	O
was	O
not	O
developed	O
for	O
a	O
particular	O
installation	O
,	O
and	O
was	O
very	O
influential	O
on	O
future	O
commercial	O
software	B-Application
,	O
such	O
as	O
Esri	O
ARC/INFO	B-Application
,	O
released	O
in	O
1983	O
.	O
</s>
<s>
By	O
the	O
late	O
1970s	O
two	O
public	O
domain	O
GIS	B-Application
systems	O
(	O
MOSS	B-Application
and	O
GRASS	B-Application
GIS	I-Application
)	O
were	O
in	O
development	O
,	O
and	O
by	O
the	O
early	O
1980s	O
,	O
M&S	O
Computing	O
(	O
later	O
Intergraph	O
)	O
along	O
with	O
Bentley	O
Systems	O
Incorporated	O
for	O
the	O
CADplatform	O
,	O
Environmental	O
Systems	O
Research	O
Institute	O
(	O
ESRI	O
)	O
,	O
CARIS(Computer Aided Resource Information System )	O
,	O
and	O
ERDAS(Earth Resource Data Analysis System )	O
emerged	O
as	O
commercial	O
vendors	O
of	O
GISsoftware	O
,	O
successfully	O
incorporating	O
many	O
of	O
the	O
CGISfeatures	O
,	O
combining	O
the	O
first	O
generation	O
approach	O
to	O
separation	O
of	O
spatial	O
and	O
attribute	O
information	O
with	O
a	O
second	O
generation	O
approach	O
to	O
organizing	O
attribute	O
data	O
into	O
database	O
structures	O
.	O
</s>
<s>
In	O
1986	O
,	O
Mapping	O
Display	O
and	O
Analysis	O
System	O
(	O
MIDAS	O
)	O
,	O
the	O
first	O
desktop	O
GIS	B-Application
product	O
was	O
released	O
for	O
the	O
DOS	B-Device
operating	O
system	O
.	O
</s>
<s>
This	O
was	O
renamed	O
in	O
1990	O
to	O
MapInfo	B-Application
for	O
Windows	O
when	O
it	O
was	O
ported	O
to	O
the	O
Microsoft	B-Application
Windows	I-Application
platform	O
.	O
</s>
<s>
This	O
began	O
the	O
process	O
of	O
moving	O
GIS	B-Application
from	O
the	O
research	O
department	O
into	O
the	O
business	O
environment	O
.	O
</s>
<s>
More	O
recently	O
,	O
a	O
growing	O
number	O
of	O
free	O
,	O
open-source	O
GIS	B-Application
packages	O
run	O
on	O
a	O
range	O
of	O
operating	O
systems	O
and	O
can	O
be	O
customized	O
to	O
perform	O
specific	O
tasks	O
.	O
</s>
<s>
The	O
major	O
trend	O
of	O
the	O
21st	O
Century	O
has	O
been	O
the	O
integration	O
of	O
GIS	B-Application
capabilities	O
with	O
other	O
Information	B-General_Concept
technology	I-General_Concept
and	O
Internet	O
infrastructure	O
,	O
such	O
as	O
relational	B-Application
databases	I-Application
,	O
cloud	B-Architecture
computing	I-Architecture
,	O
software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
(	O
SAAS	B-Architecture
)	O
,	O
and	O
mobile	O
computing	O
.	O
</s>
<s>
The	O
distinction	O
must	O
be	O
made	O
between	O
a	O
singular	O
geographic	B-Application
information	I-Application
system	I-Application
,	O
which	O
is	O
a	O
single	O
installation	O
of	O
software	B-Application
and	O
data	O
for	O
a	O
particular	O
use	O
,	O
along	O
with	O
associated	O
hardware	B-Architecture
,	O
staff	O
,	O
and	O
institutions	O
(	O
e.g.	O
,	O
the	O
GIS	B-Application
for	O
a	O
particular	O
city	O
government	O
)	O
;	O
and	O
GIS	B-Application
software	I-Application
,	O
a	O
general-purpose	O
application	B-Application
program	I-Application
that	O
is	O
intended	O
to	O
be	O
used	O
in	O
many	O
individual	O
geographic	B-Application
information	I-Application
systems	I-Application
in	O
a	O
variety	O
of	O
application	O
domains	O
.	O
</s>
<s>
Starting	O
in	O
the	O
late	O
1970s	O
,	O
many	O
software	B-Application
packages	O
have	O
been	O
created	O
specifically	O
for	O
GIS	B-Application
applications	O
.	O
</s>
<s>
Esri	O
's	O
ArcGIS	B-Application
,	O
which	O
includes	O
ArcGIS	B-Application
Pro	I-Application
and	O
the	O
legacy	O
software	B-Application
ArcMap	B-Application
,	O
currently	O
dominate	O
the	O
GIS	B-Application
Market	O
.	O
</s>
<s>
Other	O
examples	O
of	O
GIS	B-Application
include	O
Autodesk	O
and	O
MapInfo	B-Application
Professional	I-Application
and	O
open	O
source	O
programs	O
such	O
as	O
QGIS	B-Application
,	O
GRASS	B-Application
GIS	I-Application
,	O
MapGuide	B-Application
,	O
and	O
Hadoop-GIS	B-Application
.	O
</s>
<s>
These	O
and	O
other	O
desktop	O
GIS	B-Application
applications	O
include	O
a	O
full	O
suite	O
of	O
capabilities	O
for	O
entering	O
,	O
managing	O
,	O
analyzing	O
,	O
and	O
visualizing	O
geographic	B-General_Concept
data	I-General_Concept
,	O
and	O
are	O
designed	O
to	O
be	O
used	O
on	O
their	O
own	O
.	O
</s>
<s>
Starting	O
in	O
the	O
late	O
1990s	O
with	O
the	O
emergence	O
of	O
the	O
Internet	O
,	O
as	O
computer	O
network	O
technology	O
progressed	O
,	O
GIS	B-Application
infrastructure	O
and	O
data	O
began	O
to	O
move	O
to	O
servers	O
,	O
providing	O
another	O
mechanism	O
for	O
providing	O
GIS	B-Application
capabilities	O
.	O
</s>
<s>
This	O
was	O
facilitated	O
by	O
standalone	O
software	B-Application
installed	O
on	O
a	O
server	B-Application
,	O
similar	O
to	O
other	O
server	B-Application
software	I-Application
such	O
as	O
HTTP	B-Application
servers	I-Application
and	O
relational	B-Application
database	I-Application
management	I-Application
systems	I-Application
,	O
enabling	O
clients	O
to	O
have	O
access	O
to	O
GIS	B-General_Concept
data	I-General_Concept
and	O
processing	O
tools	O
without	O
having	O
to	O
install	O
specialized	O
desktop	B-Application
software	I-Application
.	O
</s>
<s>
These	O
networks	O
are	O
known	O
as	O
distributed	O
GIS	B-Application
.	O
</s>
<s>
This	O
strategy	O
has	O
been	O
extended	O
through	O
the	O
Internet	O
and	O
development	O
of	O
cloud-based	B-Architecture
GIS	B-Application
platforms	O
such	O
as	O
ArcGIS	B-Application
Online	O
and	O
GIS-specialized	O
software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
(	O
SAAS	B-Architecture
)	O
.	O
</s>
<s>
The	O
use	O
of	O
the	O
Internet	O
to	O
facilitate	O
distributed	O
GIS	B-Application
is	O
known	O
as	O
Internet	O
GIS	B-Application
.	O
</s>
<s>
An	O
alternative	O
approach	O
is	O
the	O
integration	O
of	O
some	O
or	O
all	O
of	O
these	O
capabilities	O
into	O
other	O
software	B-Application
or	O
information	B-General_Concept
technology	I-General_Concept
architectures	O
.	O
</s>
<s>
One	O
example	O
is	O
a	O
spatial	B-Algorithm
extension	I-Algorithm
to	O
Object-relational	B-General_Concept
database	I-General_Concept
software	B-Application
,	O
which	O
defines	O
a	O
geometry	O
datatype	O
so	O
that	O
spatial	B-General_Concept
data	I-General_Concept
can	O
be	O
stored	O
in	O
relational	O
tables	O
,	O
and	O
extensions	O
to	O
SQL	B-Language
for	O
spatial	O
analysis	O
operations	O
such	O
as	O
overlay	B-Application
.	O
</s>
<s>
Another	O
example	O
is	O
the	O
proliferation	O
of	O
geospatial	B-General_Concept
libraries	O
and	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
e.g.	O
,	O
GDAL	B-Language
,	O
Leaflet	B-Language
,	O
D3.js	B-Language
)	O
that	O
extend	O
programming	O
languages	O
to	O
enable	O
the	O
incorporation	O
of	O
GIS	B-General_Concept
data	I-General_Concept
and	O
processing	O
into	O
custom	O
software	B-Application
,	O
including	O
web	O
mapping	O
sites	O
and	O
location-based	B-Application
services	I-Application
in	O
smartphones	B-Application
.	O
</s>
<s>
The	O
core	O
of	O
any	O
GIS	B-Application
is	O
a	O
database	O
that	O
contains	O
representations	O
of	O
geographic	O
phenomena	O
,	O
modeling	O
their	O
geometry	O
(	O
location	O
and	O
shape	O
)	O
and	O
their	O
properties	O
or	O
attributes	O
.	O
</s>
<s>
A	O
GIS	B-Application
database	O
may	O
be	O
stored	O
in	O
a	O
variety	O
of	O
forms	O
,	O
such	O
as	O
a	O
collection	O
of	O
separate	O
data	O
files	O
or	O
a	O
single	O
spatially-enabled	B-Algorithm
relational	B-Application
database	I-Application
.	O
</s>
<s>
GIS	B-Application
uses	O
spatio-temporal	O
(	O
space-time	O
)	O
location	O
as	O
the	O
key	O
index	O
variable	O
for	O
all	O
other	O
information	O
.	O
</s>
<s>
Just	O
as	O
a	O
relational	B-Application
database	I-Application
containing	O
text	O
or	O
numbers	O
can	O
relate	O
many	O
different	O
tables	O
using	O
common	O
key	O
index	O
variables	O
,	O
GIS	B-Application
can	O
relate	O
otherwise	O
unrelated	O
information	O
by	O
using	O
location	O
as	O
the	O
key	O
index	O
variable	O
.	O
</s>
<s>
Any	O
variable	O
that	O
can	O
be	O
located	O
spatially	O
,	O
and	O
increasingly	O
also	O
temporally	O
,	O
can	O
be	O
referenced	O
using	O
a	O
GIS	B-Application
.	O
</s>
<s>
These	O
GIS	B-Application
coordinates	O
may	O
represent	O
other	O
quantified	O
systems	O
of	O
temporo-spatial	O
reference	O
(	O
for	O
example	O
,	O
film	O
frame	O
number	O
,	O
stream	O
gage	O
station	O
,	O
highway	O
mile-marker	O
,	O
surveyor	O
benchmark	O
,	O
building	O
address	O
,	O
street	O
intersection	O
,	O
entrance	O
gate	O
,	O
water	O
depth	O
sounding	O
,	O
POS	O
or	O
CAD	B-Application
drawing	O
origin/units	O
)	O
.	O
</s>
<s>
Units	O
applied	O
to	O
recorded	O
temporal-spatial	O
data	O
can	O
vary	O
widely	O
(	O
even	O
when	O
using	O
exactly	O
the	O
same	O
data	O
,	O
see	O
map	B-Application
projections	I-Application
)	O
,	O
but	O
all	O
Earth-based	O
spatial	O
–	O
temporal	O
location	O
and	O
extent	O
references	O
should	O
,	O
ideally	O
,	O
be	O
relatable	O
to	O
one	O
another	O
and	O
ultimately	O
to	O
a	O
"	O
real	O
"	O
physical	O
location	O
or	O
extent	O
in	O
space	O
–	O
time	O
.	O
</s>
<s>
Related	O
by	O
accurate	O
spatial	B-General_Concept
information	I-General_Concept
,	O
an	O
incredible	O
variety	O
of	O
real-world	O
and	O
projected	O
past	O
or	O
future	O
data	O
can	O
be	O
analyzed	O
,	O
interpreted	O
and	O
represented	O
.	O
</s>
<s>
This	O
key	O
characteristic	O
of	O
GIS	B-Application
has	O
begun	O
to	O
open	O
new	O
avenues	O
of	O
scientific	O
inquiry	O
into	O
behaviors	O
and	O
patterns	O
of	O
real-world	O
information	O
that	O
previously	O
had	O
not	O
been	O
systematically	O
correlated	O
.	O
</s>
<s>
GIS	B-General_Concept
data	I-General_Concept
represents	O
phenomena	O
that	O
exist	O
in	O
the	O
real	O
world	O
,	O
such	O
as	O
roads	O
,	O
land	O
use	O
,	O
elevation	O
,	O
trees	O
,	O
waterways	O
,	O
and	O
states	O
.	O
</s>
<s>
Traditionally	O
,	O
there	O
are	O
two	O
broad	O
methods	O
used	O
to	O
store	O
data	O
in	O
a	O
GIS	B-Application
for	O
both	O
kinds	O
of	O
abstractions	O
mapping	O
references	O
:	O
raster	B-Algorithm
images	I-Algorithm
and	O
vector	O
.	O
</s>
<s>
Points	O
,	O
lines	O
,	O
and	O
polygons	B-General_Concept
represent	O
vector	O
data	O
of	O
mapped	O
location	O
attribute	O
references	O
.	O
</s>
<s>
A	O
new	O
hybrid	O
method	O
of	O
storing	O
data	O
is	O
that	O
of	O
identifying	O
point	O
clouds	O
,	O
which	O
combine	O
three-dimensional	O
points	O
with	O
RGB	O
information	O
at	O
each	O
point	O
,	O
returning	O
a	O
"	O
3D	B-Algorithm
color	I-Algorithm
image	I-Algorithm
"	O
.	O
</s>
<s>
GIS	B-Application
thematic	O
maps	O
then	O
are	O
becoming	O
more	O
and	O
more	O
realistically	O
visually	O
descriptive	O
of	O
what	O
they	O
set	O
out	O
to	O
show	O
or	O
determine	O
.	O
</s>
<s>
GIS	B-General_Concept
data	I-General_Concept
acquisition	O
includes	O
several	O
methods	O
for	O
gathering	O
spatial	B-General_Concept
data	I-General_Concept
into	O
a	O
GIS	B-Application
database	O
,	O
which	O
can	O
be	O
grouped	O
into	O
three	O
categories	O
:	O
primary	O
data	O
capture	O
,	O
the	O
direct	O
measurement	O
phenomena	O
in	O
the	O
field	O
(	O
e.g.	O
,	O
remote	B-Application
sensing	I-Application
,	O
the	O
global	O
positioning	O
system	O
)	O
;	O
secondary	O
data	O
capture	O
,	O
the	O
extraction	O
of	O
information	O
from	O
existing	O
sources	O
that	O
are	O
not	O
in	O
a	O
GIS	B-Application
form	O
,	O
such	O
as	O
paper	O
maps	O
,	O
through	O
digitization	O
;	O
and	O
data	B-Application
transfer	I-Application
,	O
the	O
copying	O
of	O
existing	O
GIS	B-General_Concept
data	I-General_Concept
from	O
external	O
sources	O
such	O
as	O
government	O
agencies	O
and	O
private	O
companies	O
.	O
</s>
<s>
Survey	O
data	O
can	O
be	O
directly	O
entered	O
into	O
a	O
GIS	B-Application
from	O
digital	O
data	O
collection	O
systems	O
on	O
survey	O
instruments	O
using	O
a	O
technique	O
called	O
coordinate	O
geometry	O
(	O
COGO	O
)	O
.	O
</s>
<s>
Positions	O
from	O
a	O
global	O
navigation	O
satellite	B-Application
system	O
(	O
GNSS	O
)	O
like	O
Global	O
Positioning	O
System	O
can	O
also	O
be	O
collected	O
and	O
then	O
imported	O
into	O
a	O
GIS	B-Application
.	O
</s>
<s>
A	O
current	O
trend	O
in	O
data	O
collection	O
gives	O
users	O
the	O
ability	O
to	O
utilize	O
field	B-Device
computers	I-Device
with	O
the	O
ability	O
to	O
edit	O
live	O
data	O
using	O
wireless	O
connections	O
or	O
disconnected	O
editing	O
sessions	O
.	O
</s>
<s>
Current	O
trend	O
is	O
to	O
utilize	O
applications	O
available	O
on	O
smartphones	B-Application
and	O
PDAs	B-Application
-	O
Mobile	B-Application
GIS	I-Application
.	O
</s>
<s>
Remotely	B-Application
sensed	I-Application
data	O
also	O
plays	O
an	O
important	O
role	O
in	O
data	O
collection	O
and	O
consist	O
of	O
sensors	O
attached	O
to	O
a	O
platform	O
.	O
</s>
<s>
Sensors	O
include	O
cameras	O
,	O
digital	O
scanners	O
and	O
lidar	O
,	O
while	O
platforms	O
usually	O
consist	O
of	O
aircraft	O
and	O
satellites	B-Application
.	O
</s>
<s>
In	O
England	O
in	O
the	O
mid	O
1990s	O
,	O
hybrid	O
kite/balloons	O
called	O
helikites	O
first	O
pioneered	O
the	O
use	O
of	O
compact	O
airborne	O
digital	O
cameras	O
as	O
airborne	O
geo-information	B-General_Concept
systems	O
.	O
</s>
<s>
Aircraft	O
measurement	O
software	B-Application
,	O
accurate	O
to	O
0.4mm	O
was	O
used	O
to	O
link	O
the	O
photographs	O
and	O
measure	O
the	O
ground	O
.	O
</s>
<s>
Soft-copy	O
workstations	O
are	O
used	O
to	O
digitize	O
features	O
directly	O
from	O
stereo	B-Algorithm
pairs	I-Algorithm
of	O
digital	O
photographs	O
.	O
</s>
<s>
These	O
systems	O
allow	O
data	O
to	O
be	O
captured	O
in	O
two	O
and	O
three	O
dimensions	O
,	O
with	O
elevations	O
measured	O
directly	O
from	O
a	O
stereo	O
pair	O
using	O
principles	O
of	O
photogrammetry	B-Application
.	O
</s>
<s>
Satellite	B-Application
remote	B-Application
sensing	I-Application
provides	O
another	O
important	O
source	O
of	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Here	O
satellites	B-Application
use	O
different	O
sensor	O
packages	O
to	O
passively	O
measure	O
the	O
reflectance	O
from	O
parts	O
of	O
the	O
electromagnetic	O
spectrum	O
or	O
radio	O
waves	O
that	O
were	O
sent	O
out	O
from	O
an	O
active	O
sensor	O
such	O
as	O
radar	O
.	O
</s>
<s>
Remote	B-Application
sensing	I-Application
collects	O
raster	B-Algorithm
data	O
that	O
can	O
be	O
further	O
processed	O
using	O
different	O
bands	O
to	O
identify	O
objects	O
and	O
classes	O
of	O
interest	O
,	O
such	O
as	O
land	O
cover	O
.	O
</s>
<s>
The	O
most	O
common	O
method	O
of	O
data	O
creation	O
is	O
digitization	O
,	O
where	O
a	O
hard	B-General_Concept
copy	I-General_Concept
map	O
or	O
survey	O
plan	O
is	O
transferred	O
into	O
a	O
digital	O
medium	O
through	O
the	O
use	O
of	O
a	O
CAD	B-Application
program	I-Application
,	O
and	O
geo-referencing	B-General_Concept
capabilities	O
.	O
</s>
<s>
With	O
the	O
wide	O
availability	O
of	O
ortho-rectified	B-General_Concept
imagery	I-General_Concept
(	O
from	O
satellites	B-Application
,	O
aircraft	O
,	O
Helikites	O
and	O
UAVs	O
)	O
,	O
heads-up	O
digitizing	O
is	O
becoming	O
the	O
main	O
avenue	O
through	O
which	O
geographic	B-General_Concept
data	I-General_Concept
is	O
extracted	O
.	O
</s>
<s>
Heads-up	O
digitizing	O
involves	O
the	O
tracing	O
of	O
geographic	B-General_Concept
data	I-General_Concept
directly	O
on	O
top	O
of	O
the	O
aerial	O
imagery	O
instead	O
of	O
by	O
the	O
traditional	O
method	O
of	O
tracing	O
the	O
geographic	O
form	O
on	O
a	O
separate	O
digitizing	B-Device
tablet	I-Device
(	O
heads-down	O
digitizing	O
)	O
.	O
</s>
<s>
A	O
digitizer	O
produces	O
vector	O
data	O
as	O
an	O
operator	O
traces	O
points	O
,	O
lines	O
,	O
and	O
polygon	B-General_Concept
boundaries	O
from	O
a	O
map	O
.	O
</s>
<s>
Scanning	B-Application
a	O
map	O
results	O
in	O
raster	B-Algorithm
data	O
that	O
could	O
be	O
further	O
processed	O
to	O
produce	O
vector	O
data	O
.	O
</s>
<s>
After	O
entering	O
data	O
into	O
a	O
GIS	B-Application
,	O
the	O
data	O
usually	O
requires	O
editing	O
,	O
to	O
remove	O
errors	O
,	O
or	O
further	O
processing	O
.	O
</s>
<s>
For	O
scanned	O
maps	O
,	O
blemishes	O
on	O
the	O
source	O
map	O
may	O
need	O
to	O
be	O
removed	O
from	O
the	O
resulting	O
raster	B-Algorithm
.	O
</s>
<s>
Converting	O
coordinates	O
from	O
one	O
datum	O
to	O
another	O
requires	O
a	O
datum	O
transformation	O
such	O
as	O
a	O
Helmert	B-Algorithm
transformation	I-Algorithm
,	O
although	O
in	O
certain	O
situations	O
a	O
simple	O
translation	B-Algorithm
may	O
be	O
sufficient	O
.	O
</s>
<s>
In	O
popular	O
GIS	B-Application
software	I-Application
,	O
data	O
projected	O
in	O
latitude/longitude	O
is	O
often	O
represented	O
as	O
a	O
Geographic	O
coordinate	O
system	O
.	O
</s>
<s>
While	O
no	O
digital	O
model	O
can	O
be	O
a	O
perfect	O
representation	O
of	O
the	O
real	O
world	O
,	O
it	O
is	O
important	O
that	O
GIS	B-General_Concept
data	I-General_Concept
be	O
of	O
a	O
high	O
quality	O
.	O
</s>
<s>
In	O
keeping	O
with	O
the	O
principle	O
of	O
homomorphism	O
,	O
the	O
data	O
must	O
be	O
close	O
enough	O
to	O
reality	O
so	O
that	O
the	O
results	O
of	O
GIS	B-Application
procedures	O
correctly	O
correspond	O
to	O
the	O
results	O
of	O
real	O
world	O
processes	O
.	O
</s>
<s>
Several	O
elements	O
of	O
data	O
quality	O
are	O
important	O
to	O
GIS	B-General_Concept
data	I-General_Concept
:	O
</s>
<s>
In	O
GIS	B-General_Concept
data	I-General_Concept
,	O
there	O
is	O
concern	O
for	O
accuracy	O
in	O
representations	O
of	O
location	O
(	O
positional	O
accuracy	O
)	O
,	O
property	O
(	O
attribute	O
accuracy	O
)	O
,	O
and	O
time	O
.	O
</s>
<s>
Resolution	O
is	O
a	O
commonly	O
used	O
expression	O
of	O
positional	O
precision	O
,	O
especially	O
in	O
raster	B-Algorithm
data	B-General_Concept
sets	I-General_Concept
.	O
</s>
<s>
A	O
general	O
acknowledgement	O
of	O
the	O
presence	O
of	O
error	O
and	O
imprecision	O
in	O
geographic	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
That	O
is	O
,	O
it	O
is	O
a	O
degree	O
of	O
general	O
doubt	O
,	O
given	O
that	O
it	O
is	O
difficult	O
to	O
know	O
exactly	O
how	O
much	O
error	O
is	O
present	O
in	O
a	O
data	B-General_Concept
set	I-General_Concept
,	O
although	O
some	O
form	O
of	O
estimate	O
may	O
be	O
attempted	O
(	O
a	O
confidence	O
interval	O
being	O
such	O
an	O
estimate	O
of	O
uncertainty	O
)	O
.	O
</s>
<s>
Mathematical	O
tools	O
such	O
as	O
fuzzy	O
set	O
theory	O
are	O
commonly	O
used	O
to	O
manage	O
vagueness	O
in	O
geographic	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
The	O
degree	O
to	O
which	O
a	O
data	B-General_Concept
set	I-General_Concept
represents	O
all	O
of	O
the	O
actual	O
features	O
that	O
it	O
purports	O
to	O
include	O
.	O
</s>
<s>
The	O
most	O
recent	O
point	O
in	O
time	O
at	O
which	O
a	O
data	B-General_Concept
set	I-General_Concept
claims	O
to	O
be	O
an	O
accurate	O
representation	O
of	O
reality	O
.	O
</s>
<s>
This	O
is	O
a	O
concern	O
for	O
the	O
majority	O
of	O
GIS	B-Application
applications	O
,	O
which	O
attempt	O
to	O
represent	O
the	O
world	O
"	O
at	O
present	O
,	O
"	O
in	O
which	O
case	O
older	O
data	O
is	O
of	O
lower	O
quality	O
.	O
</s>
<s>
The	O
degree	O
to	O
which	O
the	O
representations	O
of	O
the	O
many	O
phenomena	O
in	O
a	O
data	B-General_Concept
set	I-General_Concept
correctly	O
correspond	O
with	O
each	O
other	O
.	O
</s>
<s>
Consistency	B-General_Concept
in	O
topological	O
relationships	O
between	O
spatial	O
objects	O
is	O
an	O
especially	O
important	O
aspect	O
of	O
consistency	B-General_Concept
.	O
</s>
<s>
For	O
example	O
,	O
interpolation	B-Algorithm
is	O
a	O
common	O
operation	O
used	O
in	O
many	O
ways	O
in	O
GIS	B-Application
;	O
because	O
it	O
generates	O
estimates	O
of	O
values	O
between	O
known	O
measurements	O
,	O
the	O
results	O
will	O
always	O
be	O
more	O
precise	O
,	O
but	O
less	O
certain	O
(	O
as	O
each	O
estimate	O
has	O
an	O
unknown	O
amount	O
of	O
error	O
)	O
.	O
</s>
<s>
GIS	B-Application
accuracy	O
depends	O
upon	O
source	O
data	O
,	O
and	O
how	O
it	O
is	O
encoded	O
to	O
be	O
data	O
referenced	O
.	O
</s>
<s>
High-resolution	O
digital	O
terrain	O
and	O
aerial	O
imagery	O
,	O
powerful	O
computers	O
and	O
Web	O
technology	O
are	O
changing	O
the	O
quality	O
,	O
utility	O
,	O
and	O
expectations	O
of	O
GIS	B-Application
to	O
serve	O
society	O
on	O
a	O
grand	O
scale	O
,	O
but	O
nevertheless	O
there	O
are	O
other	O
source	O
data	O
that	O
affect	O
overall	O
GIS	B-Application
accuracy	O
like	O
paper	O
maps	O
,	O
though	O
these	O
may	O
be	O
of	O
limited	O
use	O
in	O
achieving	O
the	O
desired	O
accuracy	O
.	O
</s>
<s>
In	O
developing	O
a	O
digital	O
topographic	O
database	O
for	O
a	O
GIS	B-Application
,	O
topographical	O
maps	O
are	O
the	O
main	O
source	O
,	O
and	O
aerial	O
photography	O
and	O
satellite	B-Application
imagery	O
are	O
extra	O
sources	O
for	O
collecting	O
data	O
and	O
identifying	O
attributes	O
which	O
can	O
be	O
mapped	O
in	O
layers	O
over	O
a	O
location	O
facsimile	O
of	O
scale	O
.	O
</s>
<s>
The	O
scale	O
of	O
a	O
map	O
and	O
geographical	O
rendering	O
area	O
representation	O
type	O
,	O
or	O
map	B-Application
projection	I-Application
,	O
are	O
very	O
important	O
aspects	O
since	O
the	O
information	O
content	O
depends	O
mainly	O
on	O
the	O
scale	O
set	O
and	O
resulting	O
locatability	O
of	O
the	O
map	O
's	O
representations	O
.	O
</s>
<s>
In	O
order	O
to	O
digitize	O
a	O
map	O
,	O
the	O
map	O
has	O
to	O
be	O
checked	O
within	O
theoretical	O
dimensions	O
,	O
then	O
scanned	O
into	O
a	O
raster	B-Algorithm
format	I-Algorithm
,	O
and	O
resulting	O
raster	B-Algorithm
data	O
has	O
to	O
be	O
given	O
a	O
theoretical	O
dimension	O
by	O
a	O
rubber	O
sheeting/warping	O
technology	O
process	O
known	O
as	O
georeferencing	B-General_Concept
.	O
</s>
<s>
The	O
electronic	O
and	O
other	O
equipment	O
used	O
to	O
make	O
measurements	O
for	O
GIS	B-Application
is	O
far	O
more	O
precise	O
than	O
the	O
machines	O
of	O
conventional	O
map	O
analysis	O
.	O
</s>
<s>
All	O
geographical	B-General_Concept
data	I-General_Concept
are	O
inherently	O
inaccurate	O
,	O
and	O
these	O
inaccuracies	O
will	O
propagate	O
through	O
GISoperations	O
in	O
ways	O
that	O
are	O
difficult	O
to	O
predict	O
.	O
</s>
<s>
Data	O
restructuring	O
can	O
be	O
performed	O
by	O
a	O
GIS	B-Application
to	O
convert	O
data	O
into	O
different	O
formats	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
GIS	B-Application
may	O
be	O
used	O
to	O
convert	O
a	O
satellite	B-Application
image	O
map	O
to	O
a	O
vector	O
structure	O
by	O
generating	O
lines	O
around	O
all	O
cells	O
with	O
the	O
same	O
classification	O
,	O
while	O
determining	O
the	O
cell	O
spatial	O
relationships	O
,	O
such	O
as	O
adjacency	O
or	O
inclusion	O
.	O
</s>
<s>
More	O
advanced	O
data	O
processing	O
can	O
occur	O
with	O
image	B-Algorithm
processing	I-Algorithm
,	O
a	O
technique	O
developed	O
in	O
the	O
late1960s	O
by	O
NASA	O
and	O
the	O
private	O
sector	O
to	O
provide	O
contrast	O
enhancement	O
,	O
false	O
color	O
rendering	O
and	O
a	O
variety	O
of	O
other	O
techniques	O
including	O
use	O
of	O
two	O
dimensional	O
Fourier	B-Algorithm
transforms	I-Algorithm
.	O
</s>
<s>
So	O
a	O
GIS	B-Application
must	O
be	O
able	O
to	O
convert	O
geographic	B-General_Concept
data	I-General_Concept
from	O
one	O
structure	O
to	O
another	O
.	O
</s>
<s>
Object	O
ontologies	O
have	O
gained	O
increasing	O
prominence	O
as	O
a	O
consequence	O
of	O
object-oriented	B-Language
programming	I-Language
and	O
sustained	O
work	O
by	O
Barry	O
Smith	O
and	O
co-workers	O
.	O
</s>
<s>
Spatial	B-Application
ETL	I-Application
tools	O
provide	O
the	O
data	O
processing	O
functionality	O
of	O
traditional	O
extract	O
,	O
transform	O
,	O
load(ETL )	O
software	B-Application
,	O
but	O
with	O
a	O
primary	O
focus	O
on	O
the	O
ability	O
to	O
manage	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
They	O
provide	O
GISusers	O
with	O
the	O
ability	O
to	O
translate	B-Algorithm
data	O
between	O
different	O
standards	O
and	O
proprietary	B-Application
formats	O
,	O
whilst	O
geometrically	O
transforming	O
the	O
data	O
en	O
route	O
.	O
</s>
<s>
These	O
tools	O
can	O
come	O
in	O
the	O
form	O
of	O
add-ins	O
to	O
existing	O
wider-purpose	O
software	B-Application
such	O
as	O
spreadsheets	B-Application
.	O
</s>
<s>
GIS	B-Application
spatial	O
analysis	O
is	O
a	O
rapidly	O
changing	O
field	O
,	O
and	O
GIS	B-Application
packages	O
are	O
increasingly	O
including	O
analytical	O
tools	O
as	O
standard	O
built-in	O
facilities	O
,	O
as	O
optional	O
toolsets	O
,	O
as	O
add-ins	O
or	O
'	O
analysts	O
 '	O
.	O
</s>
<s>
In	O
many	O
instances	O
these	O
are	O
provided	O
by	O
the	O
original	O
software	B-Application
suppliers	O
(	O
commercial	O
vendors	O
or	O
collaborative	O
non	O
commercial	O
development	O
teams	O
)	O
,	O
while	O
in	O
other	O
cases	O
facilities	O
have	O
been	O
developed	O
and	O
are	O
provided	O
by	O
third	O
parties	O
.	O
</s>
<s>
Furthermore	O
,	O
many	O
products	O
offer	O
software	B-Application
development	O
kits	O
(	O
SDKs	O
)	O
,	O
programming	O
languages	O
and	O
language	O
support	O
,	O
scripting	O
facilities	O
and/or	O
special	O
interfaces	O
for	O
developing	O
one	O
's	O
own	O
analytical	O
tools	O
or	O
variants	O
.	O
</s>
<s>
The	O
increased	O
availability	O
has	O
created	O
a	O
new	O
dimension	O
to	O
business	B-General_Concept
intelligence	I-General_Concept
termed	O
"	O
spatial	O
intelligence	O
"	O
which	O
,	O
when	O
openly	O
delivered	O
via	O
intranet	O
,	O
democratizes	O
access	O
to	O
geographic	O
and	O
social	O
network	O
data	O
.	O
</s>
<s>
Geospatial	B-General_Concept
intelligence	O
,	O
based	O
on	O
GIS	B-Application
spatial	O
analysis	O
,	O
has	O
also	O
become	O
a	O
key	O
element	O
for	O
security	O
.	O
</s>
<s>
GIS	B-Application
as	O
a	O
whole	O
can	O
be	O
described	O
as	O
conversion	O
to	O
a	O
vectorial	O
representation	O
or	O
to	O
any	O
other	O
digitisation	O
process	O
.	O
</s>
<s>
Geoprocessing	O
is	O
a	O
GIS	B-Application
operation	O
used	O
to	O
manipulate	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
A	O
typical	O
geoprocessing	O
operation	O
takes	O
an	O
input	O
dataset	B-General_Concept
,	O
performs	O
an	O
operation	O
on	O
that	O
dataset	B-General_Concept
,	O
and	O
returns	O
the	O
result	O
of	O
the	O
operation	O
as	O
an	O
output	O
dataset	B-General_Concept
.	O
</s>
<s>
Common	O
geoprocessing	O
operations	O
include	O
geographic	O
feature	O
overlay	B-Application
,	O
feature	O
selection	O
and	O
analysis	O
,	O
topology	B-Architecture
processing	O
,	O
raster	B-Algorithm
processing	O
,	O
and	O
data	O
conversion	O
.	O
</s>
<s>
Thus	O
,	O
terrain	O
data	O
is	O
often	O
a	O
core	O
dataset	B-General_Concept
in	O
a	O
GIS	B-Application
,	O
usually	O
in	O
the	O
form	O
of	O
a	O
raster	B-Algorithm
Digital	B-Application
elevation	I-Application
model	I-Application
(	O
DEM	O
)	O
or	O
a	O
Triangulated	B-Algorithm
irregular	I-Algorithm
network	I-Algorithm
(	O
TIN	O
)	O
.	O
</s>
<s>
A	O
variety	O
of	O
tools	O
are	O
available	O
in	O
most	O
GIS	B-Application
software	I-Application
for	O
analyzing	O
terrain	O
,	O
often	O
by	O
creating	O
derivative	O
datasets	B-General_Concept
that	O
represent	O
a	O
specific	O
aspect	O
of	O
the	O
surface	O
.	O
</s>
<s>
As	O
basic	O
terrain	O
analysis	O
of	O
a	O
digital	B-Application
elevation	I-Application
model	I-Application
(	O
DEM	O
)	O
involves	O
calculation	O
of	O
slope	O
and	O
aspect	O
,	O
DEMs	O
are	O
very	O
useful	O
for	O
hydrological	O
analysis	O
.	O
</s>
<s>
Once	O
a	O
flow	O
direction	O
and	O
accumulation	O
matrix	B-Architecture
has	O
been	O
created	O
,	O
queries	O
can	O
be	O
performed	O
that	O
show	O
contributing	O
or	O
dispersal	O
areas	O
at	O
a	O
certain	O
point	O
.	O
</s>
<s>
One	O
of	O
the	O
main	O
uses	O
of	O
hydrological	O
modeling	O
is	O
in	O
environmental	B-Application
contamination	I-Application
research	I-Application
.	O
</s>
<s>
Other	O
applications	O
of	O
hydrological	O
modeling	O
include	O
groundwater	B-Application
and	I-Application
surface	I-Application
water	I-Application
mapping	I-Application
,	O
as	O
well	O
as	O
flood	O
risk	O
maps	O
.	O
</s>
<s>
Viewshed	B-Application
analysis	I-Application
predicts	O
the	O
impact	O
that	O
terrain	O
has	O
on	O
the	O
visibility	O
between	O
locations	O
,	O
which	O
is	O
especially	O
important	O
for	O
wireless	O
communications	O
.	O
</s>
<s>
Shaded	B-General_Concept
relief	O
is	O
a	O
depiction	O
of	O
the	O
surface	O
as	O
if	O
it	O
were	O
a	O
three	O
dimensional	O
model	O
lit	O
from	O
a	O
given	O
direction	O
,	O
which	O
is	O
very	O
commonly	O
used	O
in	O
maps	O
.	O
</s>
<s>
Thus	O
,	O
a	O
wide	O
variety	O
of	O
analysis	O
tools	O
have	O
analyze	O
distance	O
in	O
some	O
form	O
,	O
such	O
as	O
buffers	O
,	O
Voronoi	B-Architecture
or	I-Architecture
Thiessen	I-Architecture
polygons	I-Architecture
,	O
Cost	B-Application
distance	I-Application
analysis	I-Application
,	O
and	O
network	O
analysis	O
.	O
</s>
<s>
It	O
is	O
difficult	O
to	O
relate	O
wetlands	B-Application
maps	O
to	O
rainfall	O
amounts	O
recorded	O
at	O
different	O
points	O
such	O
as	O
airports	O
,	O
television	O
stations	O
,	O
and	O
schools	O
.	O
</s>
<s>
A	O
GIS	B-Application
,	O
however	O
,	O
can	O
be	O
used	O
to	O
depict	O
two	O
-	O
and	O
three-dimensional	O
characteristics	O
of	O
the	O
Earth	O
's	O
surface	O
,	O
subsurface	O
,	O
and	O
atmosphere	O
from	O
information	O
points	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
GIS	B-Application
can	O
quickly	O
generate	O
a	O
map	O
with	O
isopleth	O
or	O
contour	O
lines	O
that	O
indicate	O
differing	O
amounts	O
of	O
rainfall	O
.	O
</s>
<s>
A	O
two-dimensional	O
contour	O
map	O
created	O
from	O
the	O
surface	O
modeling	O
of	O
rainfall	O
point	O
measurements	O
may	O
be	O
overlaid	O
and	O
analyzed	O
with	O
any	O
other	O
map	O
in	O
a	O
GIS	B-Application
covering	O
the	O
same	O
area	O
.	O
</s>
<s>
This	O
GIS	B-Application
derived	O
map	O
can	O
then	O
provide	O
additional	O
information	O
-	O
such	O
as	O
the	O
viability	O
of	O
water	O
power	O
potential	O
as	O
a	O
renewable	O
energy	O
source	O
.	O
</s>
<s>
Similarly	O
,	O
GIS	B-Application
can	O
be	O
used	O
to	O
compare	O
other	O
renewable	O
energy	O
resources	O
to	O
find	O
the	O
best	O
geographic	O
potential	O
for	O
a	O
region	O
.	O
</s>
<s>
Additionally	O
,	O
from	O
a	O
series	O
of	O
three-dimensional	O
points	O
,	O
or	O
digital	B-Application
elevation	I-Application
model	I-Application
,	O
isopleth	O
lines	O
representing	O
elevation	O
contours	O
can	O
be	O
generated	O
,	O
along	O
with	O
slope	O
analysis	O
,	O
shaded	B-General_Concept
relief	O
,	O
and	O
other	O
elevation	O
products	O
.	O
</s>
<s>
Similarly	O
,	O
an	O
expected	O
thalweg	O
of	O
where	O
surface	O
water	O
would	O
want	O
to	O
travel	O
in	O
intermittent	O
and	O
permanent	O
streams	O
can	O
be	O
computed	O
from	O
elevation	O
data	O
in	O
the	O
GIS	B-Application
.	O
</s>
<s>
A	O
GIS	B-Application
can	O
recognize	O
and	O
analyze	O
the	O
spatial	O
relationships	O
that	O
exist	O
within	O
digitally	O
stored	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Geometric	B-Application
networks	I-Application
are	O
linear	O
networks	O
of	O
objects	O
that	O
can	O
be	O
used	O
to	O
represent	O
interconnected	O
features	O
,	O
and	O
to	O
perform	O
special	O
spatial	O
analysis	O
on	O
them	O
.	O
</s>
<s>
Geometric	B-Application
networks	I-Application
are	O
often	O
used	O
to	O
model	O
road	O
networks	O
and	O
public	O
utility	O
networks	O
,	O
such	O
as	O
electric	O
,	O
gas	O
,	O
and	O
water	O
networks	O
.	O
</s>
<s>
Dana	O
Tomlin	O
coined	O
the	O
term	O
"	O
cartographic	O
modeling	O
"	O
in	O
his	O
PhD	O
dissertation	O
(	O
1983	O
)	O
;	O
he	O
later	O
used	O
it	O
in	O
the	O
title	O
of	O
his	O
book	O
,	O
Geographic	B-Application
Information	I-Application
Systems	I-Application
and	O
Cartographic	O
Modeling	O
(	O
1990	O
)	O
.	O
</s>
<s>
Tomlin	O
used	O
raster	B-Algorithm
layers	O
,	O
but	O
the	O
overlay	B-Application
method	O
(	O
see	O
below	O
)	O
can	O
be	O
used	O
more	O
generally	O
.	O
</s>
<s>
The	O
combination	O
of	O
several	O
spatial	O
datasets	B-General_Concept
(	O
points	O
,	O
lines	O
,	O
or	O
polygons	B-General_Concept
)	O
creates	O
a	O
new	O
output	O
vector	O
dataset	B-General_Concept
,	O
visually	O
similar	O
to	O
stacking	O
several	O
maps	O
of	O
the	O
same	O
region	O
.	O
</s>
<s>
These	O
overlays	B-Application
are	O
similar	O
to	O
mathematical	O
Venn	B-Application
diagram	I-Application
overlays	B-Application
.	O
</s>
<s>
A	O
union	O
overlay	B-Application
combines	O
the	O
geographic	O
features	O
and	O
attribute	O
tables	O
of	O
both	O
inputs	O
into	O
a	O
single	O
new	O
output	O
.	O
</s>
<s>
An	O
intersect	B-Application
overlay	B-Application
defines	O
the	O
area	O
where	O
both	O
inputs	O
overlap	O
and	O
retains	O
a	O
set	O
of	O
attribute	O
fields	O
for	O
each	O
.	O
</s>
<s>
A	O
symmetric	O
difference	O
overlay	B-Application
defines	O
an	O
output	O
area	O
that	O
includes	O
the	O
total	O
area	O
of	O
both	O
inputs	O
except	O
for	O
the	O
overlapping	O
area	O
.	O
</s>
<s>
Data	O
extraction	O
is	O
a	O
GIS	B-Application
process	O
similar	O
to	O
vector	B-Application
overlay	I-Application
,	O
though	O
it	O
can	O
be	O
used	O
in	O
either	O
vector	O
or	O
raster	B-Algorithm
data	O
analysis	O
.	O
</s>
<s>
Rather	O
than	O
combining	O
the	O
properties	O
and	O
features	O
of	O
both	O
datasets	B-General_Concept
,	O
data	O
extraction	O
involves	O
using	O
a	O
"	O
clip	O
"	O
or	O
"	O
mask	O
"	O
to	O
extract	O
the	O
features	O
of	O
one	O
data	B-General_Concept
set	I-General_Concept
that	O
fall	O
within	O
the	O
spatial	O
extent	O
of	O
another	O
dataset	B-General_Concept
.	O
</s>
<s>
In	O
raster	B-Algorithm
data	O
analysis	O
,	O
the	O
overlay	B-Application
of	O
datasets	B-General_Concept
is	O
accomplished	O
through	O
a	O
process	O
known	O
as	O
"	O
local	O
operation	O
on	O
multiple	O
rasters	O
"	O
or	O
"	O
map	O
algebra	O
"	O
,	O
through	O
a	O
function	O
that	O
combines	O
the	O
values	O
of	O
each	O
raster	B-Algorithm
's	O
matrix	B-Architecture
.	O
</s>
<s>
Geostatistics	O
is	O
a	O
branch	O
of	O
statistics	O
that	O
deals	O
with	O
field	O
data	O
,	O
spatial	B-General_Concept
data	I-General_Concept
with	O
a	O
continuous	O
index	O
.	O
</s>
<s>
It	O
provides	O
methods	O
to	O
model	O
spatial	O
correlation	O
,	O
and	O
predict	O
values	O
at	O
arbitrary	O
locations	O
(	O
interpolation	B-Algorithm
)	O
.	O
</s>
<s>
This	O
is	O
due	O
to	O
the	O
limitations	O
of	O
the	O
applied	O
statistic	O
and	O
data	O
collection	O
methods	O
,	O
and	O
interpolation	B-Algorithm
is	O
required	O
to	O
predict	O
the	O
behavior	O
of	O
particles	O
,	O
points	O
,	O
and	O
locations	O
that	O
are	O
not	O
directly	O
measurable	O
.	O
</s>
<s>
Interpolation	B-Algorithm
is	O
the	O
process	O
by	O
which	O
a	O
surface	O
is	O
created	O
,	O
usually	O
a	O
raster	B-Algorithm
dataset	B-General_Concept
,	O
through	O
the	O
input	O
of	O
data	O
collected	O
at	O
a	O
number	O
of	O
sample	O
points	O
.	O
</s>
<s>
There	O
are	O
several	O
forms	O
of	O
interpolation	B-Algorithm
,	O
each	O
which	O
treats	O
the	O
data	O
differently	O
,	O
depending	O
on	O
the	O
properties	O
of	O
the	O
data	B-General_Concept
set	I-General_Concept
.	O
</s>
<s>
In	O
comparing	O
interpolation	B-Algorithm
methods	O
,	O
the	O
first	O
consideration	O
should	O
be	O
whether	O
or	O
not	O
the	O
source	O
data	O
will	O
change	O
(	O
exact	O
or	O
approximate	O
)	O
.	O
</s>
<s>
Finally	O
,	O
there	O
is	O
whether	O
a	O
method	O
is	O
global	O
(	O
it	O
uses	O
the	O
entire	O
data	B-General_Concept
set	I-General_Concept
to	O
form	O
the	O
model	O
)	O
,	O
or	O
local	O
where	O
an	O
algorithm	O
is	O
repeated	O
for	O
a	O
small	O
section	O
of	O
terrain	O
.	O
</s>
<s>
Interpolation	B-Algorithm
is	O
a	O
justified	O
measurement	O
because	O
of	O
a	O
spatial	O
autocorrelation	O
principle	O
that	O
recognizes	O
that	O
data	O
collected	O
at	O
any	O
position	O
will	O
have	O
a	O
great	O
similarity	O
to	O
,	O
or	O
influence	O
of	O
those	O
locations	O
within	O
its	O
immediate	O
vicinity	O
.	O
</s>
<s>
Digital	B-Application
elevation	I-Application
models	I-Application
,	O
triangulated	B-Algorithm
irregular	I-Algorithm
networks	I-Algorithm
,	O
edge-finding	O
algorithms	O
,	O
Thiessen	B-Architecture
polygons	I-Architecture
,	O
Fourier	O
analysis	O
,	O
(	O
weighted	O
)	O
moving	O
averages	O
,	O
inverse	O
distance	O
weighting	O
,	O
kriging	O
,	O
spline	B-Algorithm
,	O
and	O
trend	O
surface	O
analysis	O
are	O
all	O
mathematical	O
methods	O
to	O
produce	O
interpolative	O
data	O
.	O
</s>
<s>
Geocoding	B-Application
is	O
interpolating	O
spatial	O
locations	O
(	O
X	O
,	O
Y	O
coordinates	O
)	O
from	O
street	O
addresses	O
or	O
any	O
other	O
spatially	O
referenced	O
data	O
such	O
as	O
ZIP	O
Codes	O
,	O
parcel	O
lots	O
and	O
address	O
locations	O
.	O
</s>
<s>
A	O
reference	O
theme	O
is	O
required	O
to	O
geocode	B-Application
individual	O
addresses	O
,	O
such	O
as	O
a	O
road	O
centerline	O
file	O
with	O
address	O
ranges	O
.	O
</s>
<s>
The	O
software	B-Application
will	O
then	O
place	O
a	O
dot	O
approximately	O
where	O
that	O
address	O
belongs	O
along	O
the	O
segment	O
of	O
centerline	O
.	O
</s>
<s>
Geocoding	B-Application
can	O
also	O
be	O
applied	O
against	O
actual	O
parcel	O
data	O
,	O
typically	O
from	O
municipal	O
tax	O
maps	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
the	O
result	O
of	O
the	O
geocoding	B-Application
will	O
be	O
an	O
actually	O
positioned	O
space	O
as	O
opposed	O
to	O
an	O
interpolated	O
point	O
.	O
</s>
<s>
Reverse	O
geocoding	B-Application
is	O
the	O
process	O
of	O
returning	O
an	O
estimated	O
street	O
address	O
number	O
as	O
it	O
relates	O
to	O
a	O
given	O
coordinate	O
.	O
</s>
<s>
Note	O
that	O
reverse	O
geocoding	B-Application
does	O
not	O
return	O
actual	O
addresses	O
,	O
only	O
estimates	O
of	O
what	O
should	O
be	O
there	O
based	O
on	O
the	O
predetermined	O
range	O
.	O
</s>
<s>
Coupled	O
with	O
GIS	B-Application
,	O
multi-criteria	O
decision	O
analysis	O
methods	O
support	O
decision-makers	O
in	O
analysing	O
a	O
set	O
of	O
alternative	O
spatial	O
solutions	O
,	O
such	O
as	O
the	O
most	O
likely	O
ecological	O
habitat	O
for	O
restoration	O
,	O
against	O
multiple	O
criteria	O
,	O
such	O
as	O
vegetation	O
cover	O
or	O
roads	O
.	O
</s>
<s>
GIS	B-Application
MCDA	O
may	O
reduce	O
costs	O
and	O
time	O
involved	O
in	O
identifying	O
potential	O
restoration	O
sites	O
.	O
</s>
<s>
GIS	B-Application
or	O
spatial	B-General_Concept
data	I-General_Concept
mining	I-Application
is	O
the	O
application	O
of	O
data	B-Application
mining	I-Application
methods	O
to	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Data	B-Application
mining	I-Application
,	O
which	O
is	O
the	O
partially	O
automated	O
search	O
for	O
hidden	O
patterns	O
in	O
large	O
databases	O
,	O
offers	O
great	O
potential	O
benefits	O
for	O
applied	O
GIS-baseddecisionmaking	O
.	O
</s>
<s>
Cartography	O
is	O
the	O
design	O
and	O
production	O
of	O
maps	O
,	O
or	O
visual	O
representations	O
of	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
The	O
vast	O
majority	O
of	O
modern	O
cartography	O
is	O
done	O
with	O
the	O
help	O
of	O
computers	O
,	O
usually	O
using	O
GIS	B-Application
but	O
production	O
of	O
quality	O
cartography	O
is	O
also	O
achieved	O
by	O
importing	O
layers	O
into	O
a	O
design	O
program	O
to	O
refine	O
it	O
.	O
</s>
<s>
Web	B-Application
Map	I-Application
Servers	I-Application
facilitate	O
distribution	O
of	O
generated	O
maps	O
through	O
web	O
browsers	O
using	O
various	O
implementations	O
of	O
web-based	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
AJAX	B-Device
,	O
Java	B-Language
,	O
Flash	B-Operating_System
,	O
etc	O
.	O
</s>
<s>
An	O
archeochrome	O
is	O
a	O
new	O
way	O
of	O
displaying	O
spatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Topographic	O
maps	O
show	O
the	O
shape	O
of	O
land	O
surface	O
with	O
contour	O
lines	O
or	O
with	O
shaded	B-General_Concept
relief	O
.	O
</s>
<s>
Today	O
,	O
graphic	O
display	O
techniques	O
such	O
as	O
shading	B-General_Concept
based	O
on	O
altitude	B-Application
in	O
a	O
GIS	B-Application
can	O
make	O
relationships	O
among	O
map	O
elements	O
visible	O
,	O
heightening	O
one	O
's	O
ability	O
to	O
extract	O
and	O
analyze	O
information	O
.	O
</s>
<s>
For	O
example	O
,	O
two	O
types	O
of	O
data	O
were	O
combined	O
in	O
a	O
GIS	B-Application
to	O
produce	O
a	O
perspective	B-Architecture
view	I-Architecture
of	O
a	O
portion	O
of	O
San	O
Mateo	O
County	O
,	O
California	O
.	O
</s>
<s>
The	O
digital	B-Application
elevation	I-Application
model	I-Application
,	O
consisting	O
of	O
surface	O
elevations	O
recorded	O
on	O
a	O
30-meter	O
horizontal	O
grid	O
,	O
shows	O
high	O
elevations	O
as	O
white	O
and	O
low	O
elevation	O
as	O
black	O
.	O
</s>
<s>
A	O
GIS	B-Application
was	O
used	O
to	O
register	O
and	O
combine	O
the	O
two	O
images	O
to	O
render	O
the	O
three-dimensional	O
perspective	B-Architecture
view	I-Architecture
looking	O
down	O
the	O
San	O
Andreas	O
Fault	O
,	O
using	O
the	O
Thematic	O
Mapper	O
image	O
pixels	O
,	O
but	O
shaded	B-General_Concept
using	O
the	O
elevation	O
of	O
the	O
landforms	O
.	O
</s>
<s>
In	O
recent	O
years	O
there	O
has	O
been	O
a	O
proliferation	O
of	O
free-to-use	O
and	O
easily	O
accessible	O
mapping	O
software	B-Application
such	O
as	O
the	O
proprietary	B-Application
web	O
applications	O
Google	O
Maps	O
and	O
Bing	O
Maps	O
,	O
as	O
well	O
as	O
the	O
free	B-License
and	I-License
open-source	I-License
alternative	O
OpenStreetMap	O
.	O
</s>
<s>
These	O
services	O
give	O
the	O
public	O
access	O
to	O
huge	O
amounts	O
of	O
geographic	B-General_Concept
data	I-General_Concept
,	O
perceived	O
by	O
many	O
users	O
to	O
be	O
as	O
trustworthy	O
and	O
usable	O
as	O
professional	O
information	O
.	O
</s>
<s>
Some	O
of	O
them	O
,	O
like	O
Google	O
Maps	O
and	O
OpenLayers	B-Language
,	O
expose	O
an	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
that	O
enable	O
users	O
to	O
create	O
custom	O
applications	O
.	O
</s>
<s>
These	O
toolkits	O
commonly	O
offer	O
street	O
maps	O
,	O
aerial/satellite	O
imagery	O
,	O
geocoding	B-Application
,	O
searches	O
,	O
and	O
routing	O
functionality	O
.	O
</s>
<s>
Web	O
mapping	O
has	O
also	O
uncovered	O
the	O
potential	O
of	O
crowdsourcing	O
geodata	B-General_Concept
in	O
projects	O
like	O
OpenStreetMap	O
,	O
which	O
is	O
a	O
collaborative	O
project	O
to	O
create	O
a	O
free	O
editable	O
map	O
of	O
the	O
world	O
.	O
</s>
<s>
These	O
mashup	B-Application
projects	O
have	O
been	O
proven	O
to	O
provide	O
a	O
high	O
level	O
of	O
value	O
and	O
benefit	O
to	O
end	O
users	O
outside	O
that	O
possible	O
through	O
traditional	O
geographic	B-General_Concept
information	I-General_Concept
.	O
</s>
<s>
Since	O
its	O
origin	O
in	O
the	O
1960s	O
,	O
GIS	B-Application
has	O
been	O
used	O
in	O
an	O
ever-increasing	O
range	O
of	O
applications	O
,	O
corroborating	O
the	O
widespread	O
importance	O
of	O
location	O
and	O
aided	O
by	O
the	O
continuing	O
reduction	O
in	O
the	O
barriers	O
to	O
adopting	O
geospatial	B-General_Concept
technology	O
.	O
</s>
<s>
The	O
perhaps	O
hundreds	O
of	O
different	O
uses	O
of	O
GIS	B-Application
can	O
be	O
classified	O
in	O
several	O
ways	O
:	O
</s>
<s>
Topic	O
:	O
the	O
domains	O
in	O
which	O
GIS	B-Application
is	O
applied	O
largely	O
fall	O
into	O
those	O
concerned	O
with	O
the	O
human	O
world	O
(	O
e.g.	O
,	O
economics	O
,	O
politics	O
,	O
transportation	O
,	O
education	O
,	O
landscape	O
architecture	O
,	O
archaeology	O
,	O
urban	O
planning	O
,	O
real	O
estate	O
,	O
public	O
health	O
,	O
crime	O
mapping	O
,	O
national	O
defense	O
)	O
,	O
and	O
those	O
concerned	O
with	O
the	O
natural	O
world	O
(	O
e.g.	O
,	O
geology	O
,	O
biology	O
,	O
oceanography	O
,	O
climate	O
)	O
.	O
</s>
<s>
That	O
said	O
,	O
one	O
of	O
the	O
powerful	O
capabilities	O
of	O
GIS	B-Application
and	O
the	O
spatial	O
perspective	O
of	O
geography	O
is	O
their	O
integrative	O
ability	O
to	O
compare	O
disparate	O
topics	O
,	O
and	O
many	O
applications	O
are	O
concerned	O
with	O
multiple	O
domains	O
.	O
</s>
<s>
Institution	O
:	O
GIS	B-Application
has	O
been	O
implemented	O
in	O
a	O
variety	O
of	O
different	O
kinds	O
of	O
institutions	O
:	O
government	O
(	O
at	O
all	O
levels	O
from	O
municipal	O
to	O
international	O
)	O
,	O
business	O
(	O
of	O
all	O
types	O
and	O
sizes	O
)	O
,	O
non-profit	O
organizations	O
(	O
even	O
churches	O
)	O
,	O
as	O
well	O
as	O
personal	O
uses	O
.	O
</s>
<s>
The	O
latter	O
has	O
become	O
increasingly	O
prominent	O
with	O
the	O
rise	O
of	O
location-enabled	O
smartphones	B-Application
.	O
</s>
<s>
Lifespan	O
:	O
GIS	B-Application
implementations	O
may	O
be	O
focused	O
on	O
a	O
project	O
or	O
an	O
enterprise	O
.	O
</s>
<s>
A	O
Project	O
GIS	B-Application
is	O
focused	O
on	O
accomplishing	O
a	O
single	O
task	O
:	O
data	O
is	O
gathered	O
,	O
analysis	O
is	O
performed	O
,	O
and	O
results	O
are	O
produced	O
separately	O
from	O
any	O
other	O
projects	O
the	O
person	O
may	O
perform	O
,	O
and	O
the	O
implementation	O
is	O
essentially	O
transitory	O
.	O
</s>
<s>
An	O
Enterprise	O
GIS	B-Application
is	O
intended	O
to	O
be	O
a	O
permanent	O
institution	O
,	O
including	O
a	O
database	O
that	O
is	O
carefully	O
designed	O
to	O
be	O
useful	O
for	O
a	O
variety	O
of	O
projects	O
over	O
many	O
years	O
,	O
and	O
is	O
likely	O
used	O
by	O
many	O
individuals	O
across	O
an	O
enterprise	O
,	O
with	O
some	O
employed	O
full-time	O
just	O
to	O
maintain	O
it	O
.	O
</s>
<s>
Integration	O
:	O
Traditionally	O
,	O
most	O
GIS	B-Application
applications	O
were	O
standalone	O
,	O
using	O
specialized	O
GIS	B-Application
software	I-Application
,	O
specialized	O
hardware	B-Architecture
,	O
specialized	O
data	O
,	O
and	O
specialized	O
professionals	O
.	O
</s>
<s>
Although	O
these	O
remain	O
common	O
to	O
the	O
present	O
day	O
,	O
integrated	O
applications	O
have	O
greatly	O
increased	O
,	O
as	O
geospatial	B-General_Concept
technology	O
was	O
merged	O
into	O
broader	O
enterprise	O
applications	O
,	O
sharing	O
IT	O
infrastructure	O
,	O
databases	O
,	O
and	O
software	B-Application
,	O
often	O
using	O
enterprise	O
integration	O
platforms	O
such	O
as	O
SAP	B-Application
.	O
</s>
<s>
The	O
implementation	O
of	O
a	O
GIS	B-Application
is	O
often	O
driven	O
by	O
jurisdictional	O
(	O
such	O
as	O
a	O
city	O
)	O
,	O
purpose	O
,	O
or	O
application	O
requirements	O
.	O
</s>
<s>
Generally	O
,	O
a	O
GIS	B-Application
implementation	O
may	O
be	O
custom-designed	O
for	O
an	O
organization	O
.	O
</s>
<s>
Hence	O
,	O
a	O
GIS	B-Application
deployment	O
developed	O
for	O
an	O
application	O
,	O
jurisdiction	O
,	O
enterprise	O
,	O
or	O
purpose	O
may	O
not	O
be	O
necessarily	O
interoperable	O
or	O
compatible	O
with	O
a	O
GIS	B-Application
that	O
has	O
been	O
developed	O
for	O
some	O
other	O
application	O
,	O
jurisdiction	O
,	O
enterprise	O
,	O
or	O
purpose	O
.	O
</s>
<s>
GIS	B-Application
is	O
also	O
diverging	O
into	O
location-based	B-Application
services	I-Application
,	O
which	O
allows	O
GPS-enabled	O
mobile	O
devices	O
to	O
display	O
their	O
location	O
in	O
relation	O
to	O
fixed	O
objects	O
(	O
nearest	O
restaurant	O
,	O
gas	O
station	O
,	O
fire	O
hydrant	O
)	O
or	O
mobile	O
objects	O
(	O
friends	O
,	O
children	O
,	O
policecar	O
)	O
,	O
or	O
to	O
relay	O
their	O
position	O
back	O
to	O
a	O
central	O
server	B-Application
for	O
display	O
or	O
other	O
processing	O
.	O
</s>
<s>
The	O
Open	O
Geospatial	B-General_Concept
Consortium	O
(	O
OGC	O
)	O
is	O
an	O
international	O
industry	O
consortium	O
of	O
384companies	O
,	O
government	O
agencies	O
,	O
universities	O
,	O
and	O
individuals	O
participating	O
in	O
a	O
consensus	O
process	O
to	O
develop	O
publicly	O
available	O
geoprocessing	O
specifications	O
.	O
</s>
<s>
Open	O
interfaces	O
and	O
protocols	O
defined	O
by	O
OpenGISSpecifications	O
support	O
interoperable	O
solutions	O
that	O
"	O
geo-enable	O
"	O
the	O
Web	O
,	O
wireless	O
and	O
location-based	B-Application
services	I-Application
,	O
and	O
mainstreamIT	O
,	O
and	O
empower	O
technology	O
developers	O
to	O
make	O
complex	O
spatial	B-General_Concept
information	I-General_Concept
and	O
services	O
accessible	O
and	O
useful	O
with	O
all	O
kinds	O
of	O
applications	O
.	O
</s>
<s>
Open	O
Geospatial	B-General_Concept
Consortium	O
protocols	O
include	O
Web	B-Application
Map	I-Application
Service	I-Application
,	O
and	O
Web	O
Feature	O
Service	O
.	O
</s>
<s>
GISproducts	O
are	O
broken	O
down	O
by	O
theOGC	O
into	O
two	O
categories	O
,	O
based	O
on	O
how	O
completely	O
and	O
accurately	O
the	O
software	B-Application
follows	O
the	O
OGCspecifications	O
.	O
</s>
<s>
Compliant	O
products	O
are	O
software	B-Application
products	O
that	O
comply	O
to	O
OGC'sOpenGISSpecifications	O
.	O
</s>
<s>
Implementing	O
products	O
are	O
software	B-Application
products	O
that	O
implement	O
OpenGISSpecifications	O
but	O
have	O
not	O
yet	O
passed	O
a	O
compliance	O
test	O
.	O
</s>
<s>
The	O
condition	O
of	O
the	O
Earth	O
's	O
surface	O
,	O
atmosphere	O
,	O
and	O
subsurface	O
can	O
be	O
examined	O
by	O
feeding	O
satellite	B-Application
data	O
into	O
a	O
GIS	B-Application
.	O
</s>
<s>
The	O
satellite	B-Application
sensor	O
output	O
used	O
to	O
generate	O
a	O
vegetation	O
graphic	O
is	O
produced	O
for	O
example	O
by	O
the	O
advanced	O
very-high-resolution	O
radiometer	O
(	O
AVHRR	O
)	O
.	O
</s>
<s>
The	O
satellite	B-Application
sensor	O
produces	O
images	O
of	O
a	O
particular	O
location	O
on	O
the	O
Earth	O
twice	O
a	O
day	O
.	O
</s>
<s>
AVHRR	O
and	O
more	O
recently	O
the	O
moderate-resolution	B-Application
imaging	I-Application
spectroradiometer	I-Application
(	O
MODIS	B-Application
)	O
are	O
only	O
two	O
of	O
many	O
sensor	O
systems	O
used	O
for	O
Earth	O
surface	O
analysis	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
integration	O
of	O
time	O
in	O
environmental	O
studies	O
,	O
GIS	B-Application
is	O
also	O
being	O
explored	O
for	O
its	O
ability	O
to	O
track	O
and	O
model	O
the	O
progress	O
of	O
humans	O
throughout	O
their	O
daily	O
routines	O
.	O
</s>
<s>
In	O
this	O
data	B-General_Concept
set	I-General_Concept
,	O
the	O
populations	O
of	O
cities	O
are	O
shown	O
for	O
daytime	O
and	O
evening	O
hours	O
highlighting	O
the	O
pattern	O
of	O
concentration	O
and	O
dispersion	O
generated	O
by	O
North	O
American	O
commuting	O
patterns	O
.	O
</s>
<s>
Using	O
models	O
to	O
project	O
the	O
data	O
held	O
by	O
a	O
GISforward	O
in	O
time	O
have	O
enabled	O
planners	O
to	O
test	O
policy	O
decisions	O
using	O
spatial	B-Application
decision	I-Application
support	I-Application
systems	I-Application
.	O
</s>
<s>
Tools	O
and	O
technologies	O
emerging	O
from	O
the	O
World	O
Wide	O
Web	O
Consortium	O
's	O
Semantic	O
Web	O
are	O
proving	O
useful	O
for	O
data	B-General_Concept
integration	I-General_Concept
problems	O
in	O
information	O
systems	O
.	O
</s>
<s>
This	O
in	O
turn	O
allows	O
a	O
GIS	B-Application
to	O
focus	O
on	O
the	O
intended	O
meaning	O
of	O
data	O
rather	O
than	O
its	O
syntax	O
or	O
structure	O
.	O
</s>
<s>
For	O
example	O
,	O
reasoning	O
that	O
a	O
land	O
cover	O
type	O
classified	O
as	O
deciduous	O
needleleaf	O
trees	O
in	O
one	O
dataset	B-General_Concept
is	O
a	O
specialization	O
or	O
subset	O
of	O
land	O
cover	O
type	O
forest	O
in	O
another	O
more	O
roughly	O
classified	O
dataset	B-General_Concept
can	O
help	O
a	O
GIS	B-Application
automatically	O
merge	O
the	O
two	O
datasets	B-General_Concept
under	O
the	O
more	O
general	O
land	O
cover	O
classification	O
.	O
</s>
<s>
Also	O
,	O
simpler	O
ontologies	O
and	O
semantic	O
metadata	O
standards	O
are	O
being	O
proposed	O
by	O
the	O
W3C	O
Geo	O
Incubator	O
Group	O
to	O
represent	O
geospatial	B-General_Concept
data	I-General_Concept
on	O
the	O
web	O
.	O
</s>
<s>
GeoSPARQL	B-General_Concept
is	O
a	O
standard	O
developed	O
by	O
the	O
Ordnance	O
Survey	O
,	O
United	O
States	O
Geological	O
Survey	O
,	O
Natural	O
Resources	O
Canada	O
,	O
Australia	O
's	O
Commonwealth	O
Scientific	O
and	O
Industrial	O
Research	O
Organisation	O
and	O
others	O
to	O
support	O
ontology	O
creation	O
and	O
reasoning	O
using	O
well-understood	O
OGC	O
literals	O
(	O
GML	O
,	O
WKT	O
)	O
,	O
topological	O
relationships	O
(	O
Simple	O
Features	O
,	O
RCC8	O
,	O
DE-9IM	O
)	O
,	O
RDF	O
and	O
the	O
SPARQL	B-Language
database	O
query	O
protocols	O
.	O
</s>
<s>
Recent	O
research	O
results	O
in	O
this	O
area	O
can	O
be	O
seen	O
in	O
the	O
International	O
Conference	O
on	O
Geospatial	B-General_Concept
Semantics	O
and	O
the	O
Terra	O
Cognita	O
–	O
Directions	O
to	O
the	O
Geospatial	B-General_Concept
Semantic	O
Web	O
workshop	O
at	O
the	O
International	O
Semantic	O
Web	O
Conference	O
.	O
</s>
<s>
With	O
the	O
popularization	O
of	O
GIS	B-Application
in	O
decision	O
making	O
,	O
scholars	O
have	O
begun	O
to	O
scrutinize	O
the	O
social	O
and	O
political	O
implications	O
of	O
GIS	B-Application
.	O
</s>
<s>
GIS	B-Application
can	O
also	O
be	O
misused	O
to	O
distort	O
reality	O
for	O
individual	O
and	O
political	O
gain	O
.	O
</s>
<s>
It	O
has	O
been	O
argued	O
that	O
the	O
production	O
,	O
distribution	O
,	O
utilization	O
,	O
and	O
representation	O
of	O
geographic	B-General_Concept
information	I-General_Concept
are	O
largely	O
related	O
with	O
the	O
social	O
context	O
and	O
has	O
the	O
potential	O
to	O
increase	O
citizen	O
trust	O
in	O
government	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
the	O
20th	O
century	O
,	O
GIS	B-Application
began	O
to	O
be	O
recognized	O
as	O
tools	O
that	O
could	O
be	O
used	O
in	O
the	O
classroom	O
.	O
</s>
<s>
The	O
benefits	O
of	O
GIS	B-Application
in	O
education	O
seem	O
focused	O
on	O
developing	O
spatial	O
cognition	O
,	O
but	O
there	O
is	O
not	O
enough	O
bibliography	O
or	O
statistical	O
data	O
to	O
show	O
the	O
concrete	O
scope	O
of	O
the	O
use	O
of	O
GIS	B-Application
in	O
education	O
around	O
the	O
world	O
,	O
although	O
the	O
expansion	O
has	O
been	O
faster	O
in	O
those	O
countries	O
where	O
the	O
curriculum	O
mentions	O
them	O
.	O
</s>
<s>
GIS	B-Application
seem	O
to	O
provide	O
many	O
advantages	O
in	O
teaching	O
geography	O
because	O
they	O
allow	O
for	O
analyses	O
based	O
on	O
real	O
geographic	B-General_Concept
data	I-General_Concept
and	O
also	O
help	O
raise	O
many	O
research	O
questions	O
from	O
teachers	O
and	O
students	O
in	O
classrooms	O
.	O
</s>
<s>
GIS	B-Application
is	O
proven	O
as	O
an	O
organization-wide	O
,	O
enterprise	O
and	O
enduring	O
technology	O
that	O
continues	O
to	O
change	O
how	O
local	O
government	O
operates	O
.	O
</s>
<s>
Government	O
agencies	O
have	O
adopted	O
GIS	B-Application
technology	O
as	O
a	O
method	O
to	O
better	O
manage	O
the	O
following	O
areas	O
of	O
government	O
organization	O
:	O
</s>
<s>
Economic	O
development	O
departments	O
use	O
interactive	O
GIS	B-Application
mapping	O
tools	O
,	O
aggregated	O
with	O
other	O
data	O
(	O
demographics	O
,	O
labor	O
force	O
,	O
business	O
,	O
industry	O
,	O
talent	O
)	O
along	O
with	O
a	O
database	O
of	O
available	O
commercial	O
sites	O
and	O
buildings	O
in	O
order	O
to	O
attract	O
investment	O
and	O
support	O
existing	O
business	O
.	O
</s>
<s>
The	O
Open	O
Data	O
initiative	O
is	O
pushing	O
local	O
government	O
to	O
take	O
advantage	O
of	O
technology	O
such	O
as	O
GIS	B-Application
technology	O
,	O
as	O
it	O
encompasses	O
the	O
requirements	O
to	O
fit	O
the	O
Open	O
Data/Open	O
Government	O
model	O
of	O
transparency	O
.	O
</s>
<s>
The	O
push	O
for	O
open	O
data	O
within	O
government	O
organizations	O
is	O
driving	O
the	O
growth	O
in	O
local	O
government	O
GIS	B-Application
technology	O
spending	O
,	O
and	O
database	O
management	O
.	O
</s>
