Unmanned Aerial Vehicle - Services & Background
(Also referred to as Unmanned Aircraft Systems [UAS] or, when appropriate, small Unmanned Aircraft Systems [sUAS]. See below for UAV information and links to company websites.)
Services
GIS Ag Maps works with georeferenced UAV imagery in similar ways as it does with satellite imagery. Contact GIS Ag Maps if you have questions about applying UAV imagery.
Featured UAV: PrecisionHawk Lancaster (access PrecsionHawk website for more information)
There are many uses for UAVs. For crop agriculture, benefits and purposes include crop scouting, yield prediction mapping, management zone development, as well as precision fertilizer, herbicide, pesticide, and seeding applications. Many countries can use UAVs for commercial purposes; however, UAVs cannot be used in the USA for commercial purposes (there is an ongoing effort to be able to use UAVs for commercial purposes in the USA).
UAV advantages and disadvantages in providing static imagery
Main advantages include: 1) It is more likely that imagery can be acquired when needed with a UAV than with other platforms, such as satellites or airplanes; 2) Imagery has very high resolution (typically, one to two inches); 3) Imagery can be processed quickly.
Main disadvantage include: 1) UAVs are susceptible to damage from wind, landing, and other causes; 2) There is no universally accepted equation (as there is with satellite data) to convert digital number (DNs) to reflectance; typically this has been done, in part, by calibrating DNs in the field based on ground reflectance measurements; 3) Clouds may enter the imaging area of interest during flight, or cloud opacity may change during flight
Main considerations about particular UAVs
1) The type of image processing is included. UAVs need complex image processing. For example, because it is commonly necessary to mosaic images from a flight to encompass an area of interest (UAVs have small individual scenes compared to satellites), then the different mosaiced images correspond to different solar elevations because they are acquired over time (with all else being equal, higher solar elevation corresponds to more brightness and radiance) - this needs to be accounted for in image processing; 2) How they depart and land (hand or machine propelled); 3) Are they fixed-wing or do they hover; 4) The amount of flights they are designed for; 5) Are flights pre-planned or controlled by portable computer; 6) The type of sensors available. UAVs are typically equipped with visible wavelength cameras but increasingly can be equipped with NIR cameras. Visible imagery under clouds has similar applications to visible imagery in clear skies, but whether NIR imagery under cloud cover is useful to any extent needs to be established. However, even if it is necessary to wait until skies are clear enough (and wind is suitable) for a UAV to acquire NIR imagery, the likelihood that NIR imagery of a field can be acquired when it is most useful will undoubtedly be increased by applying UAVs compared to satellites.
A small portion of UAV producers are listed below (links are to company websites and open in new tabs):