This document provides an overview of map algebra, which is an analysis language for performing spatial analysis on raster data. It describes the main operators in map algebra, including arithmetic, boolean, combinatorial, logical, and relational operators. It also outlines different function types in map algebra, such as local functions that apply calculations independently to each cell, global functions that apply calculations based on all cell values, focal functions that apply calculations within a neighborhood focus, and zonal functions that apply calculations within zones.

1. MAP ALGEBRA
By: Ehsan Hamzei 810392121

2. INTRODUCTION
 Map Algebra is an analysis language based loosely on the map algebra concepts
presented by Dr. Dana Tomlin in his book entitled Geographic Information
Systems and Cartographic Modeling(Tomlin, 1990)
 Map Algebra is a high-level computational language used for performing
cartographic spatial analysis using raster data.

3. MAP ALGEBRA OPERATORS
Arithmetic
operators
Boolean
operators
Combinatorial
operators
Logical
operators
Relational
operators

4. ARITHMETIC OPERATORS
 Arithmetic operators allow addition, subtraction, multiplication, and division.
 Arithmetic operators can also be used to convert values from one measurement
to another (Example: feet x 0.3048 = meters).

5. RELATIONAL OPERATORS
 Relational operators allow you to build logical tests returning values of true (1)
and false (0).
You can ether use the Relational Operator (=,<,>)
of the Abbreviation (EQ,LT, GT)

6. BOOLEAN OPERATORS
 Boolean operators such as "and", "or", and "not" allow you to chain logical tests.
Like relational operators, Boolean operators return values of true and false.
 Example: slopes that are "greater-than" 45 degrees "and" that have an elevation that is
"greater-than" 5000 meters

7. LOGICAL OPERATORS
The logical operators DIFF, IN, and OVER, also allow you to build logical tests on
a cell-by-cell basis, but are implemented with specific rules.
A DIFF B: If a cell value in raster A and raster B are different, the cell value in raster A is
returned. If the cell values are the same, the value zero is returned.
A IN {value list}: If a cell value in raster A is in the value list, the cell value in raster A is
returned. Otherwise, No Data is returned.

8. COMBINATORIAL OPERATORS
 Combinatorial operators combine the attributes of multiple input rasters.
These operators find all unique combinations of values and assign a unique ID to
each, which is then returned to the output grid.

9. GRID FUNCTIONTYPE
Local
functions
Global
functions
Zonal
functions
Focal
functions

10. LOCAL FUNCTIONS
 Local functions apply an independent calculation to only one input grid cell for
each output cell.
Example: Sin(X)

11. GLOBAL FUNCTIONS
 Global functions apply a calculation based on all cell values .
Example: flow accumulation

12. FOCAL FUNCTIONS
 Focal functions apply one calculation to all input grid cells within a “focus”.
Example: Focal Mean

13. ZONAL FUNCTIONS
 Zonal functions apply one calculation to all input grid cells within each zone
Example: Zonal Sum

14. TNX FORYOUR ATTENTION