Overlap Analysis

Introduction

This routine uses range edge files prepared in location analysis options. It will analyse the overlap of each range outline in the file, or of each range outline on the locations in another file

Range Overlap (2D)

This calculates the overlap of each range on each other. The resulting overlap matrix (.csv), contains both the percentages and the absolute areas of overlap for each range with each other. Each row in the file contains the rangeID followed by overlap on that range of the range in each column ( i.e. the overlap of the range in the row by the range in the column). The percentages file is automatically loaded to Stats Viewer, and can also be opened in Excel. The ‘Make Selections’ button can be used to select a subset of ranges for the analysis.

It is also possible to create new edge files (.edg) from the overlaps; these will be displayed in the map panel when the analysis completes. There are two options:

New range per overlapped pair

This builds a new range for each pair of ranges containing the overlap between them.

Union of overlaps

This creates one range for each input range containing the union of overlaps with all the other ranges.

Overlap of Ranges on Locations

This option estimates the proportion of locations from file A that fall within the edges of file B. The resulting overlap matrix is saved to a file (.csv )containing the proportion of locations from ranges in each column that occur within the outline of the range in each row. The file is automatically loaded to the Statistics window, and can also be opened in Excel. The Make Selections button can be used to select a subset of ranges and/or locations for the analysis.