Bathymetry Point

Data Format(s): Bathymetry Point

Coordinate system: Grid CS = Universal Transverse Mercator; Map Proj = Transverse Mercator; Horiz. Datum = NAD83; Vert. Datum = CGD28 - CDN

Abstract:
Over the course of 50 years the Ontario Ministry of Natural Resources and Forestry (OMNRF) has captured bathymetry data for over 10,000 lakes across Ontario. In 1968 the Department of Lands and Forests initiated the Aquatic Habitat Inventory Program to collect information for Ontario’s inland water data. One product was a series of contour maps showing lake depth. In many cases, these maps still represent the only authoritative source of bathymetry data for lakes in Ontario. These maps have been converted to digital GIS data which has resulted in the vast majority of the current data in the Bathymetry Line data class. More recent bathymetric data has been collected using sonar and GPS technology. This modern technique creates lake depth points (spot depths) rather than contours. This point data is stored in the Bathymetry Point data class. Bathymetry Points indicate the measurement of water depth at various places in a body of water, and are often called spot depths. The data in this layer has primarily been collected using a depth measurement device, such as an echo-sounder, in combination with a GPS for horizontal positioning. However, other survey methods such as bathymetric LiDAR may also have been used. Please see the Bathymetry Index layer for the survey method used in each water body. The points in this layer are the source data for all bathymetric data and should be used (when available) for the creation of bathymetric derivative products such as rasters, TINs and depth contours. Point densities will vary by water body and within water bodies, depending on the parameters or the survey. Bathymetry point and line data should not be used for navigational purposes. For more information visit lio@ontario.ca.