OBM - DTM - Retired

Data Format(s): Unavailable

Coordinate system: Grid CS = Geographic (Lat, Long); Map Proj = Not Applicable; Horiz. Datum = NAD83; Vert. Datum = Not Applicable

Abstract:
Point features identifying variations in elevation on the earth's surface (x, y and z values). Includes: Hydrographic Break Lines Transportation Break Lines Physical Break Lines Mass Points OBM-DTM is not available for all areas of the province. Derived from the Ontario Base Mapping (OBM) program OBM-DTM cover entities were only collected for those photogrammetric map sheets compiled on or about 1985. DTM coverage is not available for all areas of the province. Mass points were collected every 60 metres for the 1:10,000 scale and 100 metres for the 1:20,000. Breaklines were collected at a density to accurately reflect the shape of the feature if plotted at compilation scale, typically more than 3 times the density of the mass points. Legislated or Legal Authority for Collection: None Additional Time Period Information: As specified in the description, the OBM-DTM cover entities were only collected for those photogrammetric map sheets compiled on or about 1993. OBM-DTM has been retired. The data is no longer maintained/supported and future maintenance will not occur. Northern Ontario: Nominal Scale of Photography: 1:50000 Absolute Positional Accuracy: 10 metre Absolute Vertical Accuracy: 5 metre Contour Interval: 10 metre DTM Spacing (max): 100 metre Southern Ontario: Nominal Scale of Photography: 1:30000 Absolute Positional Accuracy: 5 metre Absolute Vertical Accuracy: 2.5 metre Contour Interval: 5 metre DTM Spacing (max): 60 metre Ninety percent of all spot elevations will be accurate to within the following tolerances: Vertical Accuracy: 2.5 metres Compilation Scale: 1:20000 Vertical Accuracy: 1.25 metres Compilation Scale: 1:10000