FAQ - AEROCam

FREQUENTLY ASKED QUESTIONS

What resolution does AEROCam offer?

Resolution is a comparison of pixel size in the image to the actual distance in meters on the ground. To obtain an image with a one meter resolution, the aircraft has to fly 6,000 feet above the ground (AGL). This creates an image where one pixel equals one meter in actual distance on the ground. To create a higher resolution, the aircraft flies lower to the ground and to create a lower resolution image the aircraft flies higher above the ground.

AEROCam images are offered in 1 meter, 1.5 meter, or 2 meter resolutions. It may be possible to collect higher resolution images such as 0.5 meter or .25 meter, but are done on a case by case basis. Site characteristics such as elevation, topography, landmarks, etc. will be considered when determining whether or not we will be able to collect the images at a higher resolution.

In selecting the desired image resolution, there are many factors to consider. At 0.5 meter resolution, AEROCam is required to fly over the site at 3,000 ft Above Ground Level (AGL), 6,000 ft AGL for 1 meter and so on. The maximum altitude that AEROCam can fly is 12,500 ft above sea level (MSL). It is possible to go higher for short periods of time (1/2 hr or less) if the site is small in area (approximately 1 square mile). Depending on the elevation of the site, we may only be able to collect images at 0.5m or 1 meter resolution. Topography also controls the altitude at which the site can be flown and in mountainous terrain we may only be able to safely fly the site at 1 meter or lower resolution.

Featureless terrain can create problems in creating ortho-images when processing the images. A lower resolution may be desired to simplify the rectification process. Agricultural fields or similar areas that change from year to year make it difficult to locate suitable Ground Control Points (GCP's) on the reference image when rectifying the raw images. By flying at a higher altitude (decreasing the resolution), a larger area on the ground is in the image increasing the amount of possible GCP's.

COLOR INFRARED (CIR)	VISIBLE (RGB)


Click images for larger image.

What color bands combinations does AEROCam offer?

Images can be collected in two different sets of 3-band combinations either Color Infrared (CIR) or Red, Green, Blue (RGB). CIR images (NIR, red, and green color bands) are useful in viewing subtle variances in vegetation and evaluating features such as crop health, insect damage, weed infestation, and heat stress. RGB (red, green, and blue color bands) images appear normal, as your eye would see things, making them easier to interpret for evaluating spatial characteristics of the site such as roads or field boundaries, which can be valuable for mapping purposes among other things.

What types of applications are AEROCam images used for?

The sky is the limit when it comes to aerial imagery. New uses and applications of aerial imagery are being discovered every day. Some of the more common uses are things such as; precision agriculture, research, range management, forest management, and vegetative analysis.

What area does AEROCam cover?

AEROCam primarily collects images in the states that belong to the Upper Midwest Aerospace Consortium (UMAC), which includes North Dakota, South Dakota, Montana, Wyoming, and Idaho. We are willing to collect images in neighboring states if we have the necessary resources to do so.

What time of year is AEROCam imagery offered?

A typical season starts around May 15th and can go as long as October 15th but varies from year to year due to aircraft availability.

What data will I receive if I request AEROCam images?

The typical data you receive for each site and acquisition date will consist of the unrectified raw images, with at-sensor radiance pixel values, a shapefile and PDF file of the image center points, and a "data description list" explaining each file included.

How will I receive the raw data?

The primary method of data delivery is through the use of our FTP site. We upload your images and related data in a folder to ftp://ftp.umac.org from which you will be able to download your folder of images. Once we have processed the images and uploaded your folder the contacts indicated on the form will be sent an email notifying them that the images, in a specified folder, are available to be downloaded. Images will be left online for 30 days from the date of the email notification before being removed.

Data can also be burned to a DVD and sent through the mail to the Primary Contact if you do not have access to the internet or use a dial-up connection.

Are the images geo-rectified?

Geo-rectification refers to the process of lining up each individual AEROCam image with a reference image that has known geographical coordinates. This allows your AEROCam imagery to be more easily compared with other imagery or datasets, and produces a "mosaiced" set of imagery for your site. However, we do not have an automated way to geo-rectify your images, so doing this is a very labor intensive process. Therefore, we prefer that you geo-rectify your own images if you have the resources to do so. If you don't have the resources, and your project requires geo-rectification, special arrangements should be made prior to data acquisition.

More specifically, our priorities will be to perform geo-rectification as follows:

For those that don't have their own resources, and whose projects are 1 square mile or less in area with resolution of 1 meter or lower;
For those that don't have their own resources, and whose projects are larger in size or have higher spatial resolution than above; and
We may be able assist geo-rectification of remaining projects, as time allows.

Ultimately, our own available time and resources determines how much rectification we will be able to do. Arrangements for AEROCam to geo-rectify your images should be agreed upon and made prior to the collection of the data.

Each year we attempt to geo-rectify as many of the images we collect as possible for those sites that are less than 20 square miles, but it all depends on our resources available each season. You may wait and see if we get to your images at the end of the season, but they may not be rectified in a timely enough manner to serve their purpose.

What are some of the resources available in requesting AEROCam data?

We encourage users to get involved with someone at one of the many UMAC schools listed below so that data can be shared and utilized in as many applications as possible. Links to these various schools and their contacts can be found by going to our people pages on the UMAC website. Find the nearest UMAC contact and call or email them about wanting to receive AEROCam imagery. Many of the UMAC contacts have received data from AEROCam in the past and can assist you in your request as well as provide a great resource for information.

How do I get aerial imagery from AEROCam?

Just download the "Data Request Form" document off this webpage, fill in the information, and email, fax, or mail it to the contact at the bottom of the form along with a shapefile of the area of interest. An informational sheet is also available to download for questions relating to the "Data Request Form." Send us your request no later than April 15th, to be considered for the upcoming season.