Fundimentals of GIS - Exam 4 Study Guide

Neighborhood function

Spatial operation: Output location based on calucaltion based on values of cells surrounded a target cells

Local function

Saptial operation: output location - operation on a single cell at a time (using onyl that cell’s own value)

Global function

Spatial operation: output location, comes from use of all cells across entire raster to compute an output

Zonal function

Spatial operation: calucaltions within defined zones (cells sharing same values / smae region)

Resampling

Changing raster’s cell size / reprojecting - estimating new cells values from orginal data

Mask

Restircts analysis to a specific area - cells outside the mask are excluded

• like clip

Extent

Geographic bounding box of raster dataset; defined by min and max X and Y cordinates

• where in space raster sits

Resolution

Size of each cell in a raster

• finer resoulation = smaller cells = more detial + larger file size

Con function

conditional function

• assigns output values based on whether a condition is true or false

Cost surface

Cumulative cost (distance, time, friction) of traceling from a source across the landscape

• more frinction = more expensive

Reclassifcation

reassigning cell values to new categories

• simpligy / group raster values

Slope

rate of change in eevelation over distance

• rise over run x 100

Aspect

compass direction that a slop faces (degrese)

• influences solar radiaiton, moisture, veg pattern

Curvature

Rate of change in slop

• unions

indicate whether a surface is concave (bowl) convex (hill) or flat

Viewshed

Areas visible from one or mote observer points on a surfce

• towers

Ortho

Orthropohot: aerial / satellite image that has been geometricaly corrected to reove distorions from terrain + camera angle = uniform scale

Contour lines

Lines connecting points of equal elevation on map

• tighter = higher

TIN

Triangulated Irregular Network: vector based model made of non-overlapping triangles connecting irregulary spaced elevation points