An orthophoto is a geometrically corrected aerial photograph. It is generated when variations in scale and displacements, caused by tilt of the aircraft and terrain relief, are removed from the aerial photograph by a process called orthophoto rectification. This allows for ground features to be displayed in their true ground position with a constant scale throughout the image.
All BC Government orthophotos are provided as uncompressed TIFF files in UTM projection, unless otherwise specified, and are available for selected areas of British Columbia in Black and White or Colour. Most images have a pixel resolution of 1 meter, with some colour orthophotos available at 0.5m resolution.
The BC Government also provides orthophoto mosaics, which are orthophotos that have been merged or tiled together, then clipped to the BCGS 1:20 000 map grid.
|Index Grid:||BCGS 1:20 000|
|Pixel Size (metres):||o.5 and 1.0|
|Is Lossy Compression:||No|
|Library:||BC DIS Image Warehouse|
As described in the overview an orthophoto is a geometrically corrected aerial photograph that is projected similarly to a topographical map, when viewed are displayed in their true ground position with a constant scale throughout the image.
An orthophoto allows for the direct measurement of distances, areas, and positions (if printed at scale or used in a Geographic Information System). An orthophoto may serve as a base layer onto which other map information may be placed.
No, orthophotos are delivered in an uncompressed un-tiled tiff format.
|Search using Base Map Online Store Discovery Tool||Open in Google Earth|
|Digital Orthophoto BCGS 20K Map Sheet (Map Sheets with 50-100% coverage)||$200.00 each|
|Digital Orthophoto BCGS Partial 20K Map Sheet (Map Sheets with less than 50% coverage)||$100.00 each|
Please review the following introductory materials before proceeding to the BMOS site: