Baseline Thematic Mapping

Baseline Thematic Mapping (BTM) is a program that was initiated by Base Mapping and Geomatic Services Branch (BMGS), but is now the responsibility of Corporate Information Services

The primary product is a digital thematic map depicting Land Use at a scale of 1:250 000. The digital files are Geographic Information System (GIS) compatible and are available from LandData BC (if you have registered access and a BC OnLine account). Please review the LICENSE Agreement.

Complete provincial coverage is available - BTM1. An update cycle is now underway.

The BTM Land Use Program incorporates a variety of data sources for compilation. These include: recent LANDSAT TM imagery, 1:70 000 aerial photographs, Ministry of Forests Mapgen age class information, Biogeoclimatic data, and structured digital 1:250 000 topography.

The digital BTM product is a vector based, polygonalized file in Arc shape format or in IGDS format with attribute data in dBase III+ format. There are 20 land use classes defined for the province and each polygon has a land use code, area, perimeter, elevation, slope and aspect as attributes.

• BTM1 digital product specification: Present Land Use Mapping at 1:250,000, Release 1.0 February 1995. This document describes BTM mapping procedures, data accuracy and data structure. It also defines all land use classes and database schema.
• BTM2 digital product specification: Present Land Use Mapping at 1:250 000, Release 2.1, August 2001 (Adobe Acrobat file). This document describes BTM mapping procedures, data accuracy and data structure. It also defines all land use classes and database schema.

Sample BTM Land Use map - Alkali Lake area on National Topographic Series (NTS) map (92O), 1:250 000 approximate scale.

Landsat TM satellite imagery, July 18, 1992 acquisition date for the same area as the sample BTM Land Use map. This is the primary source used to interpret the land use classes.