Transcript What is a GIS? - About IGRE | IGRE

What is a ...
G
Geographic
IInformation
System
S
. . . a conceptual definition
Real World
Abstraction
Real World
Printed
Maps
Abstraction
Representation
Real World
Printed
Maps
Abstraction
Representation
Printed
Maps
Real World
Conversion
Digital
Model
Abstraction
Representation
Printed
Maps
Real World
Conversion
Presentation
Digital
Model
Abstraction
Representation
Printed
Maps
Real World
Conversion
Analysis
Presentation
Digital
Model
Abstraction
Representation
Printed
Maps
Real World
Conversion
Analysis
Presentation
Action
Digital
Model
Abstraction
Representation
Printed
Maps
Real World
Conversion
Analysis
Presentation
Action
Digital
Model
. . . a working definition
A computer system consisting of hardware and
software that utilizes relational database
technology and a topological data structure to
allow the integration of raster and vector spatial
data with tabular information for display, edit,
query, analysis, combination, creation,
maintenance, and management of geographic
data sets in an environment that is customizable
to meet the application needs of the users
forming a powerful network of information that
facilitates the sharing of data for better decisionmaking.
. . . an operational definition
Geographic Data
Descriptive Data
Chris Buhi
Christian Carlson
Chris McGuire
Dale Loberger
Donna Buccini
Doug Ruppel
Gary Waters
Holly Williams
Jim Wojcik
Jo-Ann Brown
Joe Rubisch
Larry Young
Lee Ross
Marcia Austin
Mary Jo Fraley
Mike Dyer
Mike Rhoades
Mike Sweeney
Paul Gallimore
1757 Millbrook Ln
28226
1761 Millbrook Ln
28226
1765 Millbrook Ln
28226
1776 Millbrook Ln
28226
1780 Millbrook Ln
28226
1537 Sandberry Dr
28226
1541 Sandberry Dr
28226
1200 Yamasee Dr
28210
980 Harrowfield Rd
28226
1812 Millbrook Ln
28226
1090 Overhill Dr
28112
1108 Kings Canyon Dr 28226
1605 Bosham Ln
28226
1429 Quail Wood Dr
28226
1432 Quail Wood Dr
28226
1430 Quail Wood Dr
28226
1332 Cameron Forest Dr 28173
1327 Red Hickory Ln
28173
1429 Buckeye Ct
28173
Y
Y
Y
N
Y
Y
Y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
2
1
2
6
2
1
3
4
1
2
4
3
2
2
1
3
3
2
2
Geographic Information
N
6
Donna Buccini
1780 Millbrook Ln
Y
Jo-Ann Bro
2
1812 Millbr
Y
2
Christian Carlson
1761 Millbrook Ln
Y
Chris McGuire
1
1765 Millbrook Ln
Y
Spatial Representations
POINTS
POLYGON
LINES
NODES
ANNOTATION
Geographic Representations
POLYGON: a closed area formed by one or
more lines (eg. parcels, soil types, political
boundaries, city limits, and census tracts)
LINE: a feature defined by connecting a
series of coordinates or through a
geometric description (eg. streams, street
centerlines, parcel surveys, water lines, and gas
mains)
Geographic Representations
POINT: a feature defined by a single
coordinate (eg. maintenance hole covers, well
locations, light poles, eagle nests, survey
monuments)
NODES: features located at the
intersection of two lines (eg. street
intersections, pipe joins)
ANNOTATION: a text string placed on a
map as a graphic description (eg. street
names, and parcel or index numbers)
Geographic
Representations
Point
Line
Polygon Node
Anno
Geographic
Representations
Vector
Point
Line
Polygon Node
Anno
Each of these geographic
representations can be grouped into a
category of VECTOR data
Geographic
Representations
Vector
Point
Line
Point
Attribute
Table
Line
Attribute
Table
Polygon Node
Polygon
Attribute
Table
Node
Attribute
Table
These features are then linked to
user-defined attribute tables
Anno
Text
Attribute
Table
Spatial Relationships
(Topology)
Area Definition
Connectivity
Adjacency
Arc-Node Topology
2732
12
24
33
37
2641
41
2642
Arc-Node Topology
FNODE#
39
48
39
37
12
TNODE#
37
37
48
41
LPOLY#
0
2641
2641
0
RPOLY# 2732
LENGTH
2641
540.12
2642
297.45
2651
140.33
2642
153.56
24
33
37
2641
41
2642
PARCEL#
477
478
479
480
Polygon-Arc Topology
FNODE#
39
48
39
37
12
TNODE#
37
37
48
41
LPOLY#
0
2641
2641
0
RPOLY# 2732
LENGTH
2641
540.12
2642
297.45
2651
140.33
2642
153.56
PARCEL#
477
478
479
480
24
37
PARCEL# ARC LIST
2641
477, 478, 479
2642 33 478, 480, 481, 482
2641
41
2642
Regions & Routes
Regions
Regions & Routes
Regions
Regions & Routes
Regions
Regions & Routes
Regions
Route Systems
Regions & Routes
Regions
Route Systems
Geographic Representations
REGIONS: an extension of the polygon
feature which can define overlapping and
discontinuous areas (eg. barrier islands,
chemical applications, and trade area studies)
ROUTES: an extension of line features
which permits dynamic definition of linear,
or point, features as a segment of a line or
spanning across multiple lines (eg. street
pavement conditions, stream quality, and sewer
pipeline breaks)
Table Relationships
AREA
-8654365
65567.54
43576.22
46533.71
12
PERIM
96432.5
75343.2
46512.9
50264.2
PARCEL#
1
2
3
4
PARCEL-ID
2732
0
2641
2642
2643
PIN
0
536274
541280
539291
24
PIN
536274
541280
37
539291
OWNER
Christian Carlson
33
Chris Mguire
Dale Loberger
2641
41
2642
ADDRESS
1761 Mi
1765 Mi
1767 Mi
Why Vector?
maintains very accurate graphic
representations of map features
maintains polygon data as a single
attribute record
maintains discrete features for points,
lines, polygons, nodes, and annotation
permits the combination of data layers
while maintaining accurate graphic
representation
Discrete Raster Representations
ORIGINAL VECTOR
CELLS
Discrete Raster Representations
Value
0
1
Count
175
29
Pavement
Y
Cost
125
Continuous Raster
Representations
ORIGINAL
SAMPLE POINTS
CELLS
Continuous Raster
Representations
NO TABLE ASSOCIATED WITH
CONTINUOUS GRID DATA
Geographic Representations
CELLS: a representation of geographic
data based on rows and columns (eg.
continuous surface data such as elevation or
temperature, and categorical representations derived
from vector data)
PIXELS: a group of independent points
with a color value but no other associated
data (eg. scanned documents, orthophotography,
satellite images)
Geographic
Representations
Vector
Cell
Pixel
Point
Line
Point
Attribute
Table
Line
Attribute
Table
Polygon Node
Polygon
Attribute
Table
Node
Attribute
Table
Anno
Text
Attribute
Table
Geographic
Representations
Raster
Cell
Pixel
Vector
Point
Line
Point
Attribute
Table
Line
Attribute
Table
Polygon Node
Polygon
Attribute
Table
Node
Attribute
Table
A regular structure of rows and
columns form RASTER data
Anno
Text
Attribute
Table
Geographic
Representations
Raster
Cell
Pixel
Continuous Discrete
Value
Attribute
Table
Vector
Point
Line
Point
Attribute
Table
Line
Attribute
Table
Polygon Node
Polygon
Attribute
Table
Node
Attribute
Table
Anno
Text
Attribute
Table
Attributes can be
associated with categorical
Why Raster?
permits the display of images
allows fast data layer combinations
(raster overlays are accomplished
through map algebra statements)
better suited for analysis of continous
data or the interaction of discrete data
with continous surfaces (examples
include weighted distance models,
hydrological models, and neighborhood
analysis)
Why GIS?
Geometric
Analysis
Network
Analysis
GIS
Data
Model
Cartographic
Output
Raster
Analysis
Modeling
Interfaces
Visualization
Geometric Analysis
Buffer: create an equidistant polygon
around geographic features using a
constant or attribute value
Overlay: create a new data set by
combining two or more data sets
Query: perform graphic or tablular selection
Proximity: determine distance between
features of distinct data sets
Raster Analysis
Neighborhood Analysis: examine the
effect of proximity of cells to their
neighbors
Surface Paths: calculate optimal path
across a surface of “movement” costs
Hydrological Functions: calculate flow
across surfaces and determine
watersheds, delineate and order streams,
or model subsurface flow
Network Analysis
Optimal Path: calculate optimal path
through a linear network modeling costs
and present written directions
Nearest Facility: locate nearest facility to
a defined address or point
Linear Allocations: determine “service
areas” by allocating lines to facilities
Routing Solutions: solve linear
transportation problems such as best
order routing (“traveling salesman”)
Cartographic Output
Thematic Shading: shade polygons based
on attributes using vector or raster fill
patterns including transparent
backgrounds
Automatic Text: intelligent text labeling
and text overposting
Hybrid Display and Plot: presentation of
vector and raster data
Visualization
3D Display: display data in three
dimensional space with control over user
viewpoint
Surface Drape: drape raster or vector data
over a 3D surface
View Calculation: determine line-of-sight
or viewshed from any vantage point and
elevation
Modeling Interfaces
Third Party Applications: access to the
largest offering of third party applications
for any GIS software
. . . a working definition (again)
A computer system consisting of hardware and
software that utilizes relational database
technology and a topological data structure to
allow the integration of raster and vector spatial
data with tabular information for display, edit,
query, analysis, combination, creation,
maintenance, and management of geographic
data sets in an environment that is customizable
to meet the application needs of the users
forming a powerful network of information that
facilitates the sharing of data for better decisionmaking.
Functionality
Professional
GIS
Desktop
GIS
Desktop
Mapping
Consumer Maps
Bundled Maps
Investmen
t