Getting started.
At least one point layer must be loaded into ArcMap in order to use this tool.
Sampling Intensity.
These options determine how many sample points are generated per case. The simplest option is to create a constant number of points across all cases. The trouble with this method is that it results in different sampling densities IF your domain of availability varies. Thus the second option is to define the density of sampling, and the number of points to generate is calculated on a case by case basis based on the sampling area (the domain of availability). The third option is to define the number of sampling points in an attribute field, which allows you to create your own sampling scheme rules (in cases where the two options I provide are not adequate). Note that some Sampling Form options will override the Sampling Intensity options (see the Sampling Form section for details).
Domain of Availability.
This is the area in which sampling is allowed to occur and takes the form of a circle centered around each case point. The radius can be fixed or variable (in the latter case, the radius is read from an attribute field). Using a field representing the step length is an example of a variable radius. Note that some Sampling Form options will override the Domain of Availability options (see the Sampling Form section for details).
Sampling Form.
The random sampling form generates points entirely at random within the domain of availability. This option does not affect any of the Sampling Intensity or Domain of Availability options.
The regular sampling form generates evenly spaced points at a specified interval. This option overrides all of the Sampling Intensity options (i.e. given a radius that defines the domain of availability, the number of points to generate for each case is determined by the regular interval between points).
Finally, the sampling can be based on movement parameter distributions (binned step length and turn angle distributions, and a “Bearing” field that represents the bearing of the movement from the previous point to the current point). This option overrides all of the Domain of Availability options, and the “Constant Density” option for Sampling Intensity. The Domain of Availability is determined by the upper limit to the step length distribution.
Linking data to the generated points.
If you need to acquire data from the attribute table of the original point layer (i.e. representing the “cases”) and attach it to the attribute table of the generated points, you can join the two tables together using the common unique ID field you specified. To perform the link, rightclick on the generated point layer in the ArcMap table of contents, select “Joins and Relates…”, then “Joins”. In the new form that appears, you are asked to specify the common field name in each of the tables. Press OK. If you are asked whether you would like to index a field, press Yes – it only takes a few seconds. Now if you open the attribute table of the generated points you will see all the fields from the original attribute table have been added. Note that this is a temporary join. To make the join permanent, you need to create a new shapefile (right click on the layer in the table of contents, select “Data”, then “Export Data”).
