The orthoimage data set is a complete set of cloud-free (less than 10%) orthoimages covering the Canadian landmass and created with the most accurate control data available at the time of creation. The imagery has been corrected with either provincial and aerial triangulation data or, if not available, the most accurate NTDB data. The objective is to obtain accuracy of 30 metres or better in the South and 50 metres or better in the North for a 90% level of confidence. The accuracy is evaluated for each orthoimage data set. The control data, which has been extracted from sources as mentioned above, can consist of road intersection vector data or lake/island centroids. In some cases the intersection of the centre line of surficial river [...]
Summary
The orthoimage data set is a complete set of cloud-free (less than 10%) orthoimages covering the Canadian landmass and created with the most accurate control data available at the time of creation. The imagery has been corrected with either provincial and aerial triangulation data or, if not available, the most accurate NTDB data. The objective is to obtain accuracy of 30 metres or better in the South and 50 metres or better in the North for a 90% level of confidence. The accuracy is evaluated for each orthoimage data set. The control data, which has been extracted from sources as mentioned above, can consist of road intersection vector data or lake/island centroids. In some cases the intersection of the centre line of surficial river may have been used. The control points are distributed homogeneously within the image in specific sectors. Sectors are located in the surround of the image, in the lowest and highest elevation area of the image, and in all other areas in which overlapping image base sectors are located.
The purpose is to promote the use of geomatics and educate by providing a Web and file transfer protocol (ftp) site that distributes Canada's geospatial data. The objective of the national orthoimage project is to produce a complete set of cloud-free (less than 10%) orthoimages covering the Canadian landmass using Enhanced Thematic Mapper (ETM+) data from the Landsat-7 satellite. Production, which began in fall 2000, will span a period of three to five years.
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