Aerial Imagery Data Introduction

About Aerial Data

In the summers of 2012 and 2015 aerial imagery was collected for over 11 rural municipalities in Southern Alberta. The area covered in 2012 and 2015 differ. In 2015 the MD of Foothills was added to the project. Areas in the Crowshest Pass and the MD of Ranchland were only collected in 2012. The map below indicates the areas that are available for 2015. Click here to sign up for access to the images you are interested in.

The aerial imagery is scale corrected and saved as a set of files each covering a township or quarter of a township.

The resolution of files is 0.5 meters with some areas having a 0.25 meter pixel size in 2015. The accuracy of the files is good but there is no guarantee made that the accuracy meets any particular specification and may be lower than the pixel size. The imagery is stored in the Mr. Sid file format for 2012 and ECW format for 2015.

The naming convention of each file starts with the township identifier. The first character is the Meridian followed by the 2 character Range and then the three character Township number.

The 2012 imagery has more information appended to the filename. For example: 423010_OR_20120715_0050_RGB.sid pertains to:

   Township 10, Range 23 west of the 4th Meridian.

   The OR is for Ortho.

   The 20120715 indicates the approximate date of photography, in this case July 15, 2012.

   The 0050 indicates the resolution of 0.5 metres.

   RGB indicates that the file is full color.

The overall index above is available as a pdf file on the download site. There are also more detailed indexes for each municipality available for download. Below is an example of the MD of Willow Creek index:

The area outlined in cyan on each index is the municipal boundary.

The files contained within the municipality are stored in a folder on the download site relating to the municipality name.

Files that cross municipal boundaries may be stored in the folder of an adjacent municipality. The indexes ae color coded to indicate which file is in which folder

The numbers in each township square indicate the township identifier that is used as the first part of the filenames pertaining to that area on the map.

Each township has a collection of files that pertain to it. The .sid or .ecw file is the main image file, .prj contains the map projection, .sdw is a world file, .sid.aux also contains location reference information for your GIS software.

For more information about the imagery email the data steward at [email protected]

The Erdas Imagine viewer is capable of viewing individual Mr. Sid files and ECW files that are distributed on our site. To download this free viewer us the following link or search for the Erdas ER viewer Erdas ER Viewer