Contents
What is a spatial buffer?
A buffer is a reclassification based on distance: classification of within/without a given proximity. Buffering involves measuring distance outward in directions from an object. Buffering can be done on all three types of vector data: point, line, area. The resulting buffer is a polygon file.
Why are buffering and spatial selections important to us?
Buffering is a an important and often used spatial analysis tool but there are many others that can be used in a GIS and explored by the user. Spatial overlay is a process that allows you to identify the relationships between two polygon features that share all or part of the same area.
What is a buffer zone in GIS?
In GIS, a buffer is a zone that is drawn around any point, line, or polygon that encompasses all of the area within a specified distance of the feature. This zone is drawn by a GIS in the form of a new polygon. The term buffer may also be used as a verb, as in ‘to buffer’ a feature.
How is a spatial join different from a join?
Joins attributes from one feature to another based on the spatial relationship. The target features and the joined attributes from the join features are written to the output feature class. A spatial join involves matching rows from the Join Features to the Target Features based on their relative spatial locations.
What happens when two join features are at the same distance?
When the Match Option is set to CLOSEST or CLOSEST_GEODESIC, it is possible that two or more join features are at the same distance from the target feature. When this situation occurs, one of the join features is randomly selected as the matching feature (the join feature’s FID does not influence this random selection).
Can a target feature be a polygon in spatial join?
CONTAINS —The features in the join features will be matched if a target feature contains them. The target features must be polygons or polylines. For this option, the target features cannot be points, and the join features can only be polygons when the target features are also polygons.
How are join features written to the output?
By default, all attributes of the join features are appended to attributes of the target features and copied over to the output feature class. You can define which of the attributes will be written to the output by manipulating them in the Field Map of Join Features parameter.