gus: 0262 fundamentals of gis lecture presentation 7: raster operations jeremy mennis department of...
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GUS: 0262Fundamentals of GIS
Lecture Presentation 7:
Raster Operations
Jeremy Mennis
Department of Geography and Urban Studies
Temple University
Map Algebra and Cartographic Modeling
A raster modeling language, and an approach to GIS analysis design, developed by J.K. Berry and C. Dana Tomlin in the late 1970s - early 1980s.
It now forms the basis for grid-based analysis in ArcInfo (GRID and Spatial Analyst) and other GIS packages.
Cartographic Modeling
The representation of a geographic domain through a set of raster data layers.
Tools for manipulating and transforming those data layers (map algebra).
Conventions for designing and documenting models that integrate and relate various data layers.
Structures to provide program control in the development of those models.
Map Algebra
A set of formally defined manipulations on raster data.
Operations: Fundamental mathematical and logical operations on raster data
Functions: Complex combinations of operations
Functions: Types
Higher order data manipulations on raster grids built from the more basic operators.
Local: compute on single-cell basis
Focal: compute on a neighborhood
Zonal: use zones derived from a separate grid for evaluation
Functions: Local – Multiple Values
Functions: Local - Mean
Functions: Focal – Immediate Neighborhood
Functions: Focal – Majority
MinMean
Functions: Zonal – Entire Zones
Functions: Zonal - Max
Classification
Raster reclassification: land cover
2
22
1
1
2
2
1
1
2
1
1
1
1
1
3
3
3
4
4
3
3
3
4
4
1
11
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
1 grain crops 2 orchards 3 residential 4 commercial
1 agricultural 2 non-agricultural
Classification
Raster reclassification: temperature (interval)
32
3937
42
47
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47
31
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51
55
42
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54
1
11
2
2
1
1
2
2
1
2
2
3
3
2
2
2
2
3
3
2
2
2
3
3
Grid cell value = temperature (F)
1 31 - 40 2 41 - 50 3 51 - 60
Buffer
raster surface of within/not within proximity
2
12
2
2
2
1
1
2
2
2
0
1
2
1
2
2
2
2
2
1
2
1
1
2
Spread operation from buffered feature (0)
0
10
0
0
0
1
1
0
0
0
1
1
0
1
0
0
0
0
0
1
0
1
1
0
Reclassify:
1 within 1 unit 0 not within 1 unit
Raster Overlay
+ =
Hot + Humid Index Daily high temperature
0
10
1
1
0
1
2
2
0
1
2
2
2
1
1
0
1
1
2
1
1
1
2
2
0 - mild 1 - warm 2 - hot
0 - not humid 1 - semi humid 2 - very humid
Daily high humidity
0
12
2
2
0
1
2
2
1
0
1
2
2
0
0
1
1
0
0
0
0
0
1
1
0
22
3
3
0
2
4
4
1
1
3
4
4
1
1
1
2
1
2
1
1
1
3
3
0 - very low 1 - low 2 - medium 3 - high 4 - very high
Raster Overlay
– can use addition, multiplication, etc.– can ‘weight’ certain data layers– can use any number of data layers– can’t use nominal data unless it used as
inclusionary/exclusionary by reclassification!– Be careful with ordinal data - classification impacts
the results of overlay!– Standardize interval/ratio data
Program Control: Statements and Programs
Statement: notation to represent operations and functions
e.g. NEWLAYER = LocalFUNCTION of FIRSTLAYER and SECONDLAYER
Program: notation to represent a procedure; i.e. a sequence of statements in which each statement operates on the result of a previous statement
Program Control: Programs
Program Control: Programs
Program Control: Programs
Cartographic Modeling in ArcInfo: ModelBuilder
Locating Suitable Sites for a Waste Dump
Cartographic Modeling in ArcInfo: ModelBuilder
Cartographic Modeling in ArcInfo: ModelBuilder
Cartographic Modeling in ArcInfo: ModelBuilder
Cartographic Modeling in ArcInfo: ModelBuilder
Cartographic Modeling in ArcInfo: ModelBuilder