An empirical evaluation of workshop versus survey PPGIS methods

• Examines spatial concurrence of data generated by two PPGIS methods (community workshop versus household survey).
• Weak spatial association found between workshop and survey PPGIS data on most spatial attributes.
• Results suggest workshop PPGIS data should have limited role in decision support for land use planning.

Two common approaches for collecting spatial information through public participation geographic information systems (PPGIS) include small-group workshops and broader-scale, household sampling. We evaluate the two approaches using empirical PPGIS data for the Chugach National Forest planning process where both approaches were implemented in spring of 2012. Results from a larger PPGIS survey completed in 1998 were also included in the study for comparison. We examined the spatial concurrence of the data generated by the two approaches (workshop versus survey) on multiple spatial attributes (landscape values) using three analytical methods—subsampling, resampling, and hotspot analysis. We found little to weak spatial association from the two participatory mapping methods on most landscape values. These results may be attributed to less spatial data for the workshops and to differences in measurement and sampling between the two approaches. The empirical results of low spatial concurrence raise important questions about the use of workshop participatory GIS for planning decision support. We discuss the implications and supporting rationale for using participatory mapping in community meetings.