Many issues need to be addressed before
choosing digital aerial photography. These issues are all application driven, which means that the right image for you depends on what you are planning to use it for. Thus, the selection process should begin with a careful assessment of your project objectives relative to a variety of characteristics about the image options available.
It is important to note that there will inevitably be some trade-offs in your selection of digital aerial photography. For example, large-scale aerial photos may provide lots of detail, but updated imagery may not be available every month. Also, large-scale photos may not cover a large area or perhaps may be more expensive than smaller-scale images.
Factors that must be taken into consideration include:
- area of interest versus area of coverage
- scale
- spatial resolution (pixel size)
- type of imagery (panchromatic, true color, near infrared, multispectral, hyperspectral, etc.)
- spectral resolution: When the imagery is multispectral or hyperspectral, are the right bands (at the right band width and wavelength) available?
- temporal resolution: Do I need frequent imagery of the same location?
- timing of acquisition (seasonality, leaf on, leaf off)
- ease of acquisition
- turnaround time: How soon do you need the image after it was taken?
- ground control point density: to support both the imagery as well as other derived products (digital terrain models, contours, hydrology)
- tiling schemes (when multiple images or tiles need to be joined)
- distribution format (file type and other image processing concerns)
- level of expertise required to make full use of the imagery
- the potential for development of additional geospatial products and services
- metadata
- data licensing
- cost.
