Dr. Mary T. Dooley Map Library: Aerial Photography

The Digital Map Library features two air photo collections: The Greater Mankato Area Air Photo Collection and the Minnesota Department of Transportation (MnDOT) District 7 Air Photo Collection.

The Greater Mankato Area Air Photo Collection is two unique sets of air photos from 1959 and 1967. The set from 1959 was flown at a low altitude, providing greater detail than other photo sets of the area. The second set was flown in 1967. 

The Minnesota Department of Transportation (MnDOT) District 7 Air Photo Collection is from 1957 – 2006. District 7 is in South Central Minnesota and serves 13 rural counties. These aerial photographs were used for planning road, bridge, and truck station construction, along with assessing flood areas and wetlands. This collection of over 27,000 air photos is in the process of being digitized. For information on our workflow, please see the document below.

The Minnesota Department of Transportation also donated scrapbooks of the April 1965 Flood. Photographs and newspaper clippings are digitized and available for viewing on the April 1965 Flood Story Map. 

The digitized collections are located on the University's institutional repository Cornerstone. To explore individual digitized air photos, use the Digital Map Library GIS Tool developed by graduate student Ira Raber. If you prefer using Google Earth to locate what air photos provide coverage for specific areas, below are the .kmz files with the geolocated principal points of air photos for each collection.

This physical collection of Minnesota County air photos spans from 1936-1971. Printed indexes are available for many of the photo sets to quickly locate the area of interest. Indexes are not available for all the years; the ones that the library has are indicated on the county index folders. 

Steps to Locate Air Photographs with Indexes:

1. Determine which county the desired area is located. 
2. Locate the folder of photo mosaic indexes and maps for this county. Together these form a visual key. 
3. Each county map represents one set (year) of air photos. Choose one year. 
4. Assemble the index mosaic for that year. Each piece is numbered and has an assembly diagram on the edge. 
5. Locate the desired area on the county map for the chosen year. 
6. Locate the same area on the index mosaic for that year. 
7. Copy down the alphanumeric codes surrounding the desired area. There will be more than one set of numbers. You need all of them. 
8. Air photos overlap front to back and side to side, depending on the direction of the flight line. Each string of numbers and letters refers to one photo: the flight code/project code, roll number, and frame.
9. In the air photo cabinets, locate the appropriate county and year. 
10. The folders are arranged sequentially by the alphanumeric photo codes.  
11. Locate the appropriate folder and photos. 
12. Repeat the above procedure for each year and area.

We created digital indexes on Google Earth for our most commonly requested aerial photo sets. Below are the .kmz files for these different flights. Individual pins represent the locations of the prinicipal point of aerial photos. Click on the desired pin and record the photo number, then use this to discover the physical air photo in our collections. 

Digital Indexes: