OBM Index - Retired Index de l'OBM

Data Format(s): OBM Index

Coordinate system: Grid CS = Universal Transverse Mercator; Map Proj = Transverse Mercator; Horiz. Datum = NAD83; Vert. Datum = Not Applicable

A historical Index that was used for identifying map tiles for the discontinued Ontario Base Map (OBM) product. These map tiles were based on the UTM Nad27 (May 76) coordinate system but have been transformed to NAD83 for storage. The tiles come in two sizes: • 10000m by 10000m for 1:20,000 and • 5000m by 5000m for 1:10,000 These map tiles are oriented according to UTM coordinates and the map identifier references the lower left corner. The mapsheet identifier is a 13 digit number in the following format: SSZZEEEENNNNN • SS represents scale (10 = 1:10,000 and 20 = 1:20,000) • ZZ represents the UTM zone number (15, 16, 17, 18) • EEEE are the first 4 digits of the UTM easting • NNNNN are the first 5 digits of the UTM northing Eg. 2015650054500 -1:20,000 scale map (10000m x 10000m) in UTM zone 15 with the lower left at (650000,5450000) Maps on the UTM zone boundary will be trimmed by the UTM zone boundary. NOTE: Because of the transformation from NAD27 to NAD83 coordinate systems, the location of the index tiles will appear to be shifted. The following two layers are Nad83 and can be used in place of the OBM_Index for current cartographic applications: UTM_10KM_Grid https://www.javacoeapp.lrc.gov.on.ca/geonetwork/srv/en/main.home?uuid=aa0acd7e-b6dc-443d-9cf0-2dcaf928384f UTM_5KM_Grid https://www.javacoeapp.lrc.gov.on.ca/geonetwork/srv/en/main.home?uuid=ebbf404b-8fb9-4e44-9a0f-c970c3593fb6 OBM Index has been retired. The data is no longer maintained and future maintenance will not occur.