LISA Sample Designs

Ripleys K, Morans I, and Gearys C are secondary sample designs that rely on number of samples and the local index of spatial association (LISA) map to generate new samples. See LISA maps for more information.

Ripley's K locations of new samples are based on areas with low sample density

Moran's I locations of new samples are based on areas with high sample variance

Geary's C locations of new samples are based on areas with high negative correlation

Availability

This sample design is only available for SADA files with sampled data.

Steps

These are the steps that display in the Steps Window when this sample design is selected during the step Set sampling parameters. Click on the links below for more details about the following steps.

1. See the data

2. Set up the site

3. Set GIS overlays

4. Set sampling parameters

5. Set grid specs

6. Interpolation Methods (not available for Ripleys K)

7. Correlation Modeling (not available for Ripleys K)

8. Search Neighborhood (not available for Ripleys K)

9. Set LISA parameters

10. Show the results

11. Format picture

12. Auto-document

13. Add to results gallery

Design-specific Parameters

When Ripleys K, Morans I, or Gearys C is selected during the Set sampling parameters step, the Parameters Window changes to look like the following:

image\v4ht0451.gif

See Design Core samples or Show Ghost Image for an explanation of the core vs. single point sampling options.

Under Number of Samples, only you pick is available. Enter the number of samples in the space provided.

To use the secondary minimum distance constraint, enter a value next to Separate by at least.

Under Tie Break Options, select the appropriate tie break method.

Press Show the Results on the Steps Window and SADA will display the sample locations in the Graphics Window. If there are polygons, new samples will only be placed inside the active polygons.

image\v4ht0452.gif

To view the actual coordinates of the new sample points export the information to a comma delimited excel file by using the Output to File toolbar button in main form of SADA.