SPATIAL ANALYST

With support from:

NSF DUE-0903270

Prepared by:

in partnership with:

Jennifer McKee

Geospatial Technician Education Through Virginia’s Community Colleges (GTEVCC)

SPATIAL ANALYST

• ArcGIS Extension • Provides spatial analysis & modeling tools for

vector & raster data

• Examples:– Creating new data from existing, e.g. slope or hillshade

raster from DEM– Performing distance & cost-of-travel analyses– Interpolate data values based on sample (point) data

HOW TO ACCESS S.A. TOOLS

• ArcToolbox– Must search for tool if location unknown

• Model Builder– Use tools or scripts in models

• Python– interactive command line or script

• Raster Calculator – for simple map algebra

S.A. TOOLSETS

• Broken down into catergories by ESRIConditionalDensityDistanceExtractionGeneralizationGroundwaterHydrologyInterpolationLocalMap AlgebraMath General

Math BitwiseMath LogicalMath TrigonometricMultivariateNeighborhoodOverlayRaster CreationReclassSolar RadiationSurfaceZonal

For greater details see ArcGIS 10 help or online resource center

ACCESSING S.A. TOOLS

RASTER CALCULATOR

• Simple Math Algebra

• Use interface – correct syntax is required, including spaces

R.C. EXAMPLE

• Want to query DEM to locate all areas with 600 meters or greater elevation

"eggleston" >= 600

• Results in boolean output: 1 = true, 0 = false

R.C. EXAMPLE CONTINUED• Combining multiple boolean outputs to find an area that

meets your criteria• For example: you want to identify areas that have elevation

>= 600 meters & have a slope >= 30%1. "eggleston" >= 6002. "Slope" >= 303. "Above600m" & "slopeabove30“ OR4. ("eggleston" >= 600) & ("Slope" >= 30)

• 2 separate queries for each criteria & then combine boolean outputs

• 1 compound query for both criteria

EXERCISES• Already performed vector based spatial analysis on

Day 2 during Rodney’s Multi-Criteria Evaluation• GIS Tutorial 2 Spatial Analysis

– Tutorial 3-1 pg. 76– Tutorial 3-3 pg. 93– Tutorial 5-1 pg. 124– Tutorial 5-8 pg. 179– Tutorial 5-9 pg. 191

• MCE with Spatial Analyst (Auxiliary Materials notebook, Section 6)