Hawth's Analysis Tools for ArcGIS

SpatialEcology.Com

 You are here: Home > Hawths Tools > Tools Descriptions & Help

 Summary

GENERATE SAMPLE PLOTS (point based)
Input: a point layer that defines the center of the sampling shapes that will be created
Output: a polygon shapefile of sample plots
Features:

  • this tool generates polygon sample plots around each point
  • the user can specify one of a variety of shapes: squares, hexagons, triangles, etc
  • the size of the plot is controlled by a single parameter, which can be constant, or can vary between points

Limitations:

  • the reference layers MUST be in a projected coordinate system (this tool will produce biased results if a geographic coordinate system is used)
  • this tool is designed to work with shapefiles, other vector formats have not been tested

 Help

Getting started The point reference layer must be loaded into ArcMap before starting this tool (see below). This layer represents the center of the plot shape to be created.

Output shapefile The output of this tool is a polygon shapefile."

Plot shape Select any of the listed plot shapes from the drop-down box.

Plot dimensions The dimension of the plot polygon that is to be created can either be a constant value (one that you type in to the form when you run the tool), or variable across points (in which case you must create a numerical attribute field in the point attribute table representing the dimension before running this tool). In either case, the value of the dimension you supply has slightly different meanings for each of the sample shapes:
- SQUARES: the dimension is the distance from the center of the square to the southern boundary of the square (due south)
- CIRCLE: the dimension is the radius of the circle (note that you may wish to use the Buffer Features tool to obtain circles - it was included here only for completeness)
- DIAMOND: the dimension is the distance from the center of the diamond to the southern point of the diamond (due south)
- HEXAGON: the dimension is the distance from the center of the hexagon to the southern boundary of the hexagon (due south)
-TRIANGLE: the dimension is the distance from the center of the triangle to the southern boundary of the square (due south). Note that currently the triangles are all creates with a southern edge that runs East-West.
Note that this tool is designed to be used in conjunction with the Generate Regular Points tool to create complete vector grids of some of these sampling shapes (e.g. hexagons).

Home | Articles | Services || Hawth's Tools:  Overview | Description | Download | FAQ