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Specifications Frequently Asked Questions How to Acquire Base Mapping

A digital orthophoto is a photo-quality digital image (a raster image) of surface features in their geometrically-corrected, true map position. Multiple orthophotos can be joined together seamlessly to create an orthophoto mosaic.

Orthophoto mosaics are orthophotos that have been merged or tiled together, then clipped to the BCGS 1:20 000 map grid.

The component orthophotos are geometrically corrected aerial photographs from which variations in scale and displacements caused by terrain relief and tilt of the aircraft are removed 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 and for the direct measurement of distances, areas, and positions. An orthophoto may serve as a base layer onto which other map information may be placed.

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.

Frequently Asked Questions

1. Why is it not possible to see many of the images indicated as being available in the Image Warehouse?

The Digital Image Warehouse contains hundreds of thousands of photograph images of the province. The images are obtained from a variety of sources and technologies.

Because of the high volume of images and the file space required to maintain digital imagery as well as the high costs associated with storing images in the online production servers, thumbnails of the most current images are made available for viewing. Other imagery that is frequently used are also available to be viewed online.

Older images that are not required on a regular basis are stored in an archive area that is not on-line.

The complete catalogue of less frequently required images are listed in the search results and can be ordered at any time from the store. When an order is received these images will be recalled from the archived area, loaded onto a Compact Disc (CD) and shipped to the customer as requested.

2. What special tools do I require to view the images I am interested in obtaining from the image warehouse?

Most imagery is maintained in standard TIFF format and can be viewed using standard image viewing software available on most computers in use today. More specialized use of the imagery for research and analysis will require special viewing tools.

Images stored in the Image warehouse are large files. Viewers that support large file sizes will be able to display these images.

Some image viewing software can be found at the following web sites;

How to Acquire

Search using Base Map Online Store Discovery Tool Open in Google Earth

Pricing

Digital Orthophoto Mosaic Map Sheet
Incorporates up to 25 individual 20X compressed TRIM 20K map sheets that fall within a Quarter NTS letter block, 1m resolution (e.g., 82E/SW)		 $500.00 each

Search and order using the Base Map Online Store >>

Before Using the Base Map Online Store

Please review the following introductory materials before proceeding to the BMOS site:

Requirements to Use the BMOS >> Product Brochure  >> Currency, Costs, Taxes  >> Product Delivery Times  >> Cancellations, Refunds, Discounts  >>