The first letters tell the data type, “orth” for orthophoto, “line” for a digital elevation model, “contour” for contour lines. The next 2 numbers are the UTM zone, usually 16, 17, or 18, for Ontario. The next 4 numbers are the easting value of the bottom left corner of the file, the next 5 numbers are the northing value for the bottom left corner of the tile. The next 4 digits are the year the data was captured. The last letters are the data owner, “fbs” for first base solutions, “tera” for teranet. For example, if the file name is orth171234567892012fbs.jpg. This is an orthophoto, taken by First Base Solutions in 2012. The UTM zone is 17, the X-value is 123400 and the Y-value is 5678900 for the lower left corner of the tile.
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