The Ministry of Natural Resources defines ecological units on the basis of bedrock, climate (temperature, precipitation), physiography (soils, slope, aspect) and corresponding vegetation. This enhances their compatibility with national and continental classification systems. The ecological land classification (ELC) of Ontario is used for descriptive, planning, and resource management purposes. The upper levels in its hierarchy may be relevant for provincial and municipal land-use planning initiatives. The lower (finer-scale) levels of the hierarchy are most useful for detailed resource management prescriptions and other local and site planning applications. This packaged dataset is classified into 3 hierarchical categories: * Ecozone: used for national and coarse-scale provincial reporting such as analyses of climate, demographics and watersheds * Ecoregion: used for determining the significance or status of wetland classes and certain other natural heritage features (e.g., old growth forest), setting targets for Wilderness Class Provincial parks, State of the Forest reporting and studying natural disturbance regimes * Ecodistrict used for assessing biodiversity levels, defining seed zones, mapping ecosystem types and setting targets for the identification of natural heritage systems Introduction to ecological land classification