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GIS for Environmental GIS for Environmental ScienceScience
ENSC 3603ENSC 3603
Class 7Class 72/03/092/03/09
Today's ObjectivesToday's Objectives
• Quiz
• GIS Data GeoStor Quick Start Guide
• NRCS Web Soil Survey
• Vector Data
• ArcGis, ArcCatalog
GIS DataGIS Data
• GeoStor 5 quick start guide• http://www.geostor.arkansas.gov/Portal/ptk?
command=quickstarthelp.jsp
• NRCS Web Soil Survey• http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm
DataData
•Thematic Layers•A GIS stores information about the world as a collection of thematic layers that can be linked together by geography.
DataData• Geographic data record the locations and
characteristics of natural features or human activities that occur on or near the Earths surface.
• Data Types:
• Vector Raster Surface
Vector DataVector Data
• Vector Data: A conceptual representation of geographic features.
• Vector Data Model: Object based approach to represent discrete objects.
• Vector Data Model Concepts use graphical elements: – Points– Lines or arcs– Polygons or areas– These are also known as Feature Classes
Reality as Vector DataReality as Vector Data• Real-World
entities are abstracted into three basic shapes
Points(Man-holes)
Lines(Roads, Sewer lines)
Polygons (Wetlands, Fields,Buildings)
Vector DataVector Data• Point, Line and Polygon entities.
Vector DataVector Data• Points: Chicken houses in Washington County
Vector DataVector Data• Line: Washington County Roads
Vector DataVector Data• Polygon: Washington County Soil Series
Vector DataVector Data
Raster data Structure Converted to Vector dataStructure
Vector DataVector Data
• Feature classes pertain to a particular theme such as vegetation, land parcels, drainage and transportation etc.
• Feature classes are organized into layers
• Layers only have one type of graphical element.
Vector DataVector Data
• Representing vector data differently at different scales:– Cartographic generalization – line and area
objects are represented by more coordinates at a large scale than at a small scale.
– Cartographic symbolization – Vector data are represented by different symbols that visually distinguish them from one another
Vector DataVector Data
• Topology: Spatial relationships– Adjacency: neighborhood– Containment: Inclusion of one spatial object
within another– Connectivity: Linkages among spatial
objects
Vector DataVector Data
• Topology: Spatial relationships– Adjacency:
neighborhood– Polygon C is Adjacent
to Polygons B and D
Vector DataVector Data
• Topology: Spatial relationships– Containment:
Inclusion of one spatial object within another.
Polygon A is Contained within Polygon B
Vector DataVector Data
• Topology: Spatial relationships– Connectivity:
Linkages among spatial objects.
Point A is Connected to Point B
A
B
Vector DataVector Data
• Vector-based GIS Data-Processing:– Input– Analysis– Output
Vector DataVector Data
• Input functions– Digitizing tables– Image scanning– Importing data
Vector DataVector Data
• Data input functions:– Acquisition by digitizing, purchasing,
collecting new data by GPS, surveying or photogrammetric and remote sensing methods
– Editing to clean and inspect data.– Formatting or translating to convert data to
a specific physical database format.– Linking graphical data to associated attribute
data.
Vector DataVector Data
• Analysis functions:– Nontopological Analysis:
• Attribute database query– Structured Query Language (SQL)
• Address geocoding– Or Address matching, TIGER files
• Area Calculation• Statistical computation
– Mean, max, min and standard deviation computed for items in attribute tables.
Attribute database query, Structured Query Language (SQL)
HI1
42
34
F1
D5
46
E1HI2
38
40
35
B4F2
33
G339
D3
K1
A1
A4
E2
D8
L8
AG PARK
A5
C4
C3
A3
B5
32
C2
A6
C1
K2
D6
G6
L2
D2
F8
A7
B6
L5
PV2
FD8
A3A
I3
E4
D1
38A
G2
E5
37
G4
32A
A2
E3
36
G5
D7
B7
G7
HA
I1
B3
HC
D4
B10
44
L3
I6F13
F10A
43
34B
K5
HB
FS9
34A
F9
HD6
HD7
C5E
A8
41
HD3
FD1
C5W
K3
34C
F10
HD5HH3
HD1
I4
HD4
HH2
F4
34D
C8E
C7E
C6E
K4
A2A
32B
HH3E
HH1
B8
L1A
E10
I5
C7W
C6W
G8
HD8
B9
B3
HH3C
C8W
F6
F7
G1
FS7
F5
FS6
G8A
35A
I2A
B1
E8
HH3A
FS8
L1
HH3B
F12
F11
UA
EX
HH4
PF3A
E7
E6
I2
L4A
46A
FD6
L6FD7
EN6
G10
FD5
G9
G8B
E9
L4
FD4L4B
EN5
G9A
F3
D8A
EN7
33A
HH
3D
FD
2B1AL7 F
D3
G1 0
A
36A
EN4
Arkansas Agricultural Research and Extension Center
LegendChisel plow 1994Pond
¬0 1,000 2,000500 Feet
Fields chisel plowed 1994
Attribute database query, Structured Query Language (SQL) Map Result
GeocodingGeocoding
Mapquest uses Geocoding to find
locations.
Database of address used toMap locations on a map.
Statistical computation, Mean, max, min and standard deviation computed for items in attribute tables
Field F1Soil pH
Vector DataVector Data• Topological Analysis
– Layer-based Analysis• Reclassification
– Aims to reduce categories of attribute data
• Layer-based Overlay analysis
– Topological Overlay Operators for polygon on polygon
• UNION: Keeps all area in both layers
• INTERSECT: Keeps only parts of the first layer falling within the second layer
• IDENTITY: keeps all layer features
• CLIP: Cuts out a piece of the first layer based on the second
• ERASECOV: erase part of first layer based on the second
• SPLIT: divides the first layer based on the second
• Network analysis
Vector DataVector Data
– Network analysis• Linear features that are interconnected
– Examples, highways, railways, rivers transit routes utility distribution systems.
– Example problem: Find shortest route between two points.
– Line segments and junctions can have resistance.
Vector DataVector Data
• River Network
Vector DataVector Data
– Feature-based analysis• A Buffer is a zone with a specified width that
surrounds a spatial feature.– Buffering
• Used for neighborhood analysis
• Feature-based overlay analysis– Example, point in polygon
Vector DataVector Data
• Buffering around a point
Buffering around lines
Vector DataVector Data
• Overlay analysis– Represents the world in layers– Combines human/social with
environmental– Data must be measured,
generalized, and quantified– Both visual and analytical
analysis
Types Visual, Boolean, Arithmetic
Vector DataVector Data
• Output Functions– Vector map Composition
• Graduated Symbols• Graduated Colors• Charts• Contour Lines• 3-D Perspective Views
– Vector-raster conversion
Class ProjectClass Project
A 200 word statement describing a problem to be addressed by the project. Include an:
Introduction
Objectives
Methods – Data, Software, Analysis
References
Example found at:http://www.uark.edu/depts/agronomy/farm/GISFES09/
GISFES09.HTML
For Next timeFor Next time
• Chapter 5 in Lo (2007)
• Project proposal due February 5th
• ESRI Module 2 due
"Focus not on the commotion around you, but the opportunity ahead of you." - Arnold Palmer
"Achievement is largely the product of steadily raising one's levels of aspiration and expectation." - Jack Nicklaus
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