Using a number of spatial ecological data sets and the Vegetation Resources Inventory (VRI), ESSA developed a GIS-based process to calculate key environmental metrics used to track land use change across BC Hydro’s properties.
A complete ecological land use classification for the province of BC was generated, combining VRI land cover information with ecological data, a modeled riparian layer, rarity data and landscape context layers. Each unique parcel of land, defined by the input GIS layers, was scored in four categories (land cover, landscape context, rarity, and ecological) using a custom model. Data management, QA, and process documentation were key factors in developing a methodology that could be repeated for calculating the land metric for subsequent years.
Historical VRI data was compiled and intersected with the other land cover data in ArcGIS to produce a land cover classification, with key attributes of the VRI used to classify vegetation type and forest age. Riparian habitat was modeled using a slope and cost distance analysis based on a 25 m DEM and 1:20K Fresh Water Atlas stream network.
To handle the large areal coverage and spatial complexity of the input data, a toolkit was developed to split up and batch process the land cover and ecological data layers into manageable size pieces using Python scripts. A total of 40 million parcels make up the land metric for BC, each with a unique score allowing BC Hydro to calculate and assess the impact of land use changes anywhere in the province.
The second phase of this project was to develop a web mapping application through which BC Hydro users can find properties and explore the land metric; drilling down to individual parcel scores and retrieving information on the ecological land use make-up of that parcel. ArcGIS Server and FLEX were chosen as the building blocks of this application, giving BC Hydro users the rich internet experience and ease of use required to get the most out of their data.