NATIONAL ATLAS ECODISTRICT FRAMEWORK OBJECTIVE: To produce a National Atlas Ecodistrict framework by joining the Ecodistrict framework and the 1:1 million National Atlas base. This new Atlas framework will be used as the fourth level of information in EcoMAP. BASE The most recent version of the National atlas base ( derived from Vmap0) was acquired from the NRCan GeoGratis website. These data were converted from VMap Level 0, Release 004 Vector Product Format to ArcExport format. The data are at a scale of 1:1,000,000 and covers all of Canada and have been clipped to the spatial extent of the Canadian landmass. BACKGROUND: Reliable framework data are essential for the practical use of geospatial data. It is one of the objectives of GeoConnections (http://www.geoconnections.org) to provide reliable framework datasets for Canada. The National Atlas of Canada is addressing this need by developing integrated and reliable framework datasets based on the Vector Map Level 0 (VMAP0) product. The VMAP0 data product is a global digital dataset produced and maintained by the United States National Imagery and Mapping Agency (NIMA http://www.nima.mil) at a nominal scale of 1:1,000,000. The National Atlas, in wanting to choose an international global digital map base, has adapted the VMAP0 for use as a base from which other, smaller map scales can be created and to which thematic layers can be added. The VMAP0 data were first released as the DCW (Digital Chart of the World) dataset. The DCW has been widely used and has proved to be very useful because it was the first global multitheme dataset at such a scale in the public domain. Despite its success, the DCW dataset is widely known to have had some deficiencies. The revision 4 data for North America was much better in quality, but still must be improved before it would be suitable for use by the National Atlas of Canada. The data are primarily derived from the VMAP0 Revision 4 data for North America, as distributed by NIMA in DIGEST format. These data are described in the VMAP0 Revision 4 Metadata and MIL-V-89039 documents. This document describes the primary modifications to this data, which are: 1. Conversion into Arc/Info format The data were converted to Arc/Info format using ESRI’s VPFimporter in Arc/Info 7.2.1, together with custom routines. If you are viewing the data in another format, then it has been translated. 2. Denormalisation of Attributes In its original VPF format, the attributes for the data are spread out over a number of tables using database normalisation rules. It proved more convienient for our users to have all the data placed into the feature attribute tables. This has increased the size of the database somewhat, but all the attribute information is more readily available 3. Clipping to the Canadian area These datasets cover all the land and water area of Canada. Some data outside Canada has been included for visual reference, but only the data inside Canada has been quality controlled. Watch for a later release of processed data for North America. 4. Addition and update of information in the political boundary layer The political boundary layer has been heavily modified. The international boundaries between Canada and Denmark, and Canada and the United States have been updated based on legally acceptable coordinate information. The international marine boundaries have been added, and the Nunavut boundary has been added. As a result of this processing both the oceans and bathymetry information which was available in VMAP0 is no longer available in this dataset. These data layers may be made available in a later North American release. 5. Addition and topological checking of information in the inland water areas and inland water lines hydrology layers. The VMAP0 hydrology has been enhanced by updating areas that were out of date, and improving the connectivity information. The connectivity was extensively tested using analytical methods. While errors undoubtedly remain, the dataset should now be quite topologically accurate. Additional information was also attached to the node attribute table regarding dams and sink information. This information, together with the fields in the arc attribute table and polygon attribute table are described in the following table. 6. Addition of a description field and a unique identifier A field called description has been added to each coverage and this field can be used for a simple understanding of what each feature is. Many users may find this sufficient. More advanced users may delve into the other attributes for more detailed information. Every feature in each coverage has been given a unique id # for error tracking purposes. The data have been organised into different Arc/Info coverages. These relate to, but do not exactly correspond to the original VMAP0 coverages. Within each coverage there may be a number of thematic feature classes. For instance roads and railroads are both within the transportation coverage. To date, only the hydrology and boundaries have been extensively processed by the National Atlas of Canada. Two kinds of improvements have been made to these datasets. First, improvements were made where the data are in error, out of date, or incomplete. In particular, some parts of the James Bay power project and the Nunavut territory were not properly represented. International marine boundaries were not part of the dataset, and had to be added. Certain rivers which were connected in reality were not connected in the database. The 1:1M base, when it is complete, will need to be generalised for use at smaller scales. The National Atlas of Canada has neither the time nor the personnel to do a manual generalisation of the entire country, so automated generalisation techniques will be used. These techniques require a highly topologically structured dataset, and considerable effort is being expended on topological structuring. These enhancements exceed the original specifications of the VMAP data. ECOSYSTEMS The most recent and final version of the ecodistrict frame work for the Canadian hierarchical ecological system was downloaded from the CANSIS website http://www.res.agr.ca/CANSIS/NSDB/ECOSTRAT/COVERAGE. BACKGROUND: EcoMAP uses the Ecological Framework of Canada as the common framework for data and analysis. Ecozones - first level (currently in EcoMAP) The most generalized level in the framework is the ecozone. The country was grouped according to very broad physiographic and ecological similarities into 15 ecozones. These have been described previously by Wiken (1986). Ecoprovinces - second level (currently in EcoMAP) The next level in the ecological framework is the ecoprovince. The ecozones were subdivided into smaller units based on finer categories of physiographic similarities. There are 53 units at the terrestrial ecoprovince level. Ecoprovinces are a useful ecosystem intermediate scale for national and regional planning and reporting purposes. Ecoregions - third level (currently in EcoMAP) The ecological framework is divided into a total of 194 ecoregions (217 polygons). Each ecoregion has a name, which is normally based on a prominent biophysical or physiographic feature within the ecoregion. The elements used to guide the consistent formulation of national ecoregions were the published national maps on climate (Ecoregions Working Group 1989), physiography (Bostock 1970), and existing provincial ecological frameworks. Wherever available, more detailed provincial climate and physiographic information was used, as well as geologic and vegetation cover information. Consultation between federal and provincial/territorial authorities ensured that local perceptions of the landscape were incorporated into the ecoregion construction. Ecodistricts - fourth level (now added to EcoMAP) A similar process was followed to further subdivide ecoregions into 1021 ecodistricts. Each ecodistrict is characterized by relatively homogeneous biophysical and climatic conditions. The differentiating characteristics of ecodistricts are: regional landform, local surface form, permafrost distribution, soil development, textural group, vegetation cover/land use classes, range of annual precipitation, and mean temperature. Ecodistrict size is a function of regional variability of these defining attributes, and minimum size is approximately 100,000 ha. Ecodistricts are designed for use at a map scale of 1:1 million to 1:2 million. The ecodistricts are numbered from 1 to 1031. Of these ten are considered to be empty polygons because they are totally within bodies of water i.e. Great Slave Lake. These ten ecodistricts are 172, 240, 330, 673, 719, 721, 722, 725, 842 and 845. There are also a number of very small polygons with a class number of (0) which represent water areas. ATTRIBUTES The GeoGratis ecodistrict framework has been tagged with a number of attributes to be used for display or analysis. The following table describes these attributes and the field names under which they are found in the database that accompanies the GIS file.