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Ministry of Energy, Mines and Pertoleum Resources

Digital Terrain Map Library General Description

Purpose:

The Digital Terrain Map Library provides terrain and slope stability related maps in digital format.  Maps included in the library will be from existing hardcopy maps and from new Terrain Mapping that is funded through Forest Renewal BC.   New FRBC funded mapping is required to be submitted in digital form.  Existing hardcopy maps are being converted to digital format for inclusion in the library.   The digital maps are GIS compatible and may be accessed in two ways; 1) digital maps may be downloaded for use in Geographic Information Systems or Desktop Mapping Packages or 2) the maps may be viewed, manipulated and analysed on-line with the use of the Autodesk MapGuide Viewer.  The maps are available at no cost in either case and will only be available through this WWW site.  Some raster maps are also available for download.

Map Conversion (existing hardcopy):

A major segment of this project is the conversion of existing hardcopy terrain and terrain stability maps to a digital format.  All existing maps which may be of use to terrain mappers for reference and planning purposes are planned to be converted as a part of this project.  Existing mapping has been completed to various standards for a variety of purposes.  During the conversion the objective is to capture the existing information in a digital map format rather than a simple picture format.  Most of the map conversions require digitizing of existing maps, original mylars or production mylars are used where ever possible.  The following points are relevant to understanding the conversion and capture process:

  1. Data is captured in a georeferenced format in the same datum as the original.   In most cases this is the NAD 27 datum, conversion to NAD83 will be accomplished using the National Transformation Version 2 conversion data.  Due to problems with original basemaps the new georeferenced information may not exactly overlay the original.
  2. As digital maps are useable at many scales and may be integrated with a wide variety of basemaps special digitizing conventions were used in the data capture of waterbodies and are reflected in the downloadable and on-line maps. - Existing waterbodies (oceans and lake shores) are not included, instead terrain polygons are projected out into the waterbodies.  This allows for any of the existing digital basemaps to be used with this data.  GIS operators can cut the terrain maps with the water bodies from their basemaps.   The existing digital basemaps all have different shoreline positions and shapes and this approach will cause the least problems for the most users.
  3. There are virtually always problems with linework or labeling on existing maps.   Where obvious these problems have been addressed but in many cases they can not be resolved.  Examples of problems are; multiple labels in a polygon, no label in a polygon, labels that are not described in the legend and unclosed polygons.  Where possible unresolved problems are left as documented on the map unless their inclusion in incompatible in which case they are excluded.
  4. During the capture process contiguous maps which were originally part of one project are merged into a single file.   Projects in this library are identified as FRBC_1, FRBC_9A etc.  One of these projects may contain from 1 to 16 or so original maps.  All maps in a project will have a single legend and have been produced using consistent procedures and standards.
  5. Existing hardcopy maps being added to this library have been produced over the last 20 or more years to a wide variety of standards.  The digital maps reflect the original information as close as possible, no attempt is made to reinterpret this old information in terms of the new standards for terrain mapping.

New Mapping:

All new FRBC funded terrain mapping is to be submitted in hardcopy and digital format.  The required format is described in the 1998 Terrain Database Manual Standards For Digital Terrain Capture In British Columbia, prepared for The RIC (Resources Inventory Committee)  Submitted mapping in this format will be posted directly on this site for downloading and on-line access.  It will be mapped to the TRIM base and be in NAD83.