GISP 4 GIS Analytical Methods Practice Questions and Correct Answers

Analytical method: 0verlay analysis Define problem; Break problem into submodels; Determine significant layers (some of these layers may need to be created); Reclassify or transform data within a layer Analytical method: Spatial overlay process of superimposing layers of geographic data that cover the same area to study the relationship between them Analytical method: Overlay two or more maps or layers are superimposed for showing relationships between features Vector overlay tools: ldentity Input features, split by overlay features Vector overlay tools: lntersect Only features common to all input layers Vector overlay tools: Symmetrical Difference Features common to either input layer or overlay, layer but not both Any overlap is NOT part of the result. Vector overlay tools: Union all input features Vector overlay tools: Update Input feature geometry replaced by update layer Raster overlay tools: Zonal Statistics Summarizes values in a raster layer by zones (categories) in another layer-for example, calculate the mean elevation for each vegetation category Raster overlay tools: Combine Assigns a value to each cell in the output layer based on unique combinations of values from several input layers. Raster overlay tools: Single Output Map Algebra Lets you combine multiple raster layers using an expression you enter-for example, you can add several ranked layers to create an overall ranking Raster overlay tools: Weighted Overlay Automates the raster overlay process and lets you assign weights to each layer before adding (you can also specify equal influence to create an unweighted overlay) Raster overlay tools: Weighted Sum Overlays several rasters multiplying each by their given weight and summing them together.