Frequently a limiting factor to performing valuation analysis is spatial data. While some standardized Geographic Information Systems (GIS) data sets exist for the whole United States, these public available data sets are inadequate for analysis  at a fine scale. Further, publicly available data sets often omit characteristics which are crucial to valuation. For instance, a publicly available land cover map may simply call all treed areas "forest," while a client may need to know which forests are also in riparian zones, urban areas, wetlands, etc. Our team of GIS specialists works with clients to derive new data sets through overlay analysis of existing ones and through derivation of new thematic data through field collection or remote sensing image classification.

The most common data development routine is the development of new land cover data, using a classification typology designed in conjunction with the client.  Standard land cover classification systems (e.g. the Anderson system) are inadequate for mapping differences in ecosystem services because they have many categories with high precision to describe land types that have little or no ecosystem service value (e.g. commercial, industrial, quarries, etc.), while they lack sufficient categorical precision to describe the variety of types of land that deliver different types or levels of ecosystem services (e.g. old growth vs. second growth forest). To address this, we work with clients to develop new land cover "typologies" that characterize the diversity of land types so as to account for the variation in ecosystem services in the study area. Doing this requires combing through federal, state, local and private data sets and use "geoprocessing" to combine the needed traits of each. It can also involve collecting data using GPS units in the field, or using automated methods to classify satellite or aerial imagery into categories. 

Above: Maps of digital land cover classifications developed for Humboldt County, CA (left) and for Maury Island, WA (right); click for enlargements.