A GRTS User's Manual for the SDrawNPS Package: A graphical user interface for generalized random tessellation stratified (GRTS) sampling and estimation
Starcevich L, DiDonato G, McDonald T, Mitchell J. 2016. A GRTS User's Manual for the SDrawNPS Package: A graphical user interface for generalized random tessellation stratified (GRTS) sampling and estimation. Natural Resource Report. NPS/PWRO/NRR—2016/1233. National Park Service. Fort Collins, Colorado
Spatially-balanced sampling provides a probabilistic basis for allocating sampling effort across large areas. Benefits of spatially-balanced sampling include avoidance of clustered points that can be obtained through simple random sampling and increased efficiency when the variance estimator can take advantage of the spatial balance. Many networks of the National Park Service (NPS) have incorporated spatially-balanced sampling into their monitoring programs of Vital Signs at each park. Specifically, many parks have chosen to use generalized random tessellation stratified (GRTS) sampling to obtain spatially-balanced samples of points across these extensive and heterogeneous landscapes. GRTS sample draw and analysis tools available in the R package spsurvey have been implemented in a graphical-user interface (GUI) in the SDrawNPS package. The tools available in the SDrawNPS package include: • GUI windows for drawing an equiprobable, stratified, or unequal probability GRTS sample • Options to plot the sampling frame and selected sample points • GUI windows to analyze data from a GRTS sample • Options to adjust the design weights for frame error and nonresponse error • Options to change the scope of inference based on nonresponse error This manual serves as a companion user’s manual for the SDrawNPS software package and provides statistical background on GRTS sampling, nonsampling error, weighting adjustment, and other details that arise when designing, implementing, and analyzing data from an ecological sample. The SDrawNPS software package (including example data) is provided as well.
- Type
- Published Report
- Authors
- Starcevich, Leigh Ann; DiDonato, Guy; McDonald, Trent; Mitchell, Jason
- Date of Issue
- 2016-06
- Publisher
- National Park Service
- Units
- MEDN , MOJN , NRSS , PWRO
- Keywords
- GRTS, R, sample, sampling, sampling design, SDraw, statistics