GIS CH. 11 Vector Data Analysis Terms
Line-in-polygon overlay
A GIS operation in which a line layer is dissected by the polygon boundaries on the overlay layer, and each line segment on the output combines attributes from the line layer and the polygon within which it falls
Point-in-polygon overlay
A GIS operation in which each point of a layer is assigned attribute data of the polygon within which it falls.
Polgon-onpolygon
A GIS operation in which the output combines the polygon boundaries from he inputs to crate a new set o polygons, each carrying attributes from the inputs.
Overlay
A GIS operation that combines the geometries and attributes of the input layers to create the output.
Append
A GIS operation that creates a new layer by piecing together two or more layers
Eliminate
A GIS operation that creates a new layer by removing features that meet a user defined logical expression from the input layer
Clip
A GIS operation that creates a new layer including only those features of the input layer that fall within the area extend of the clip layer
Buffering
A GIS operation that creates zones consisting of areas within a specified distance of selected features.
Split
A GIS operation that divides the input layer into two or more layers
Dissolve
A GIS operation that removes boundaries between polygons that have the same attribute value(s)
Erase
A GIS operation that removes from the input layer those features that fall within the area extent of the erase layer
Update
A GIS operation that replaces the input layer with the update layer and its features
Select
A GIS operation that uses a logical expression to select features from the input layer for the output layer
Cluster tolerance
A distance tolerance that forces points and lines to be snapped together if they fall within the specified distance.
Unon
A polygon-on-polygon overlay method that preserves all features from the input layers
Areal interpolation
A process of transferring known data from one set of polygons to another
Ripley's K function
A spatial statistic that determines whether a point pattern is random, regular, or clustered over a range of distances
Spatial autocorrelation
A spatial statistic that determines whether a point pattern is random, regular, or clustered over a range of distances.
G-statisic
A spatial statistic that measures the clustering of high and low values in a data set. The G-statistic can be either general or local
Nearest neighbor analysis
A spatial statitic that detmines if apoin paern is randon, regular, or clustered
Symmetrical Difference
An overlay method that preserves features falling within the area that is common to only one of the input layers
Identity
An overlay method that preserves only featurre that fall within the are extent defined by the identity layer
Intersect
An overlay method that preserves only those features falling within the area extent common to the input layers
Error propagation
The generation of errors in the overlay output that are due to inaccuracies of the input layers
Local Indicators of Spatial Association (LISA)
The local version of Moran's I
Minimum mapping unit
The smallest are unit that is managed b a government agency or an organization
Slivers
Very small polygons found along the shared boundary of the two input layers in overlay
