Table 9.

Comparison of satellite, aerial photography and DMSV instruments for the broad scale land mapping (study area 35 x 35km) (Kobryn, 1996).

PARAMETER
SATELLITE
HARD COPY AERIAL PHOTOGRAPHY
DMSV INSTRUMENT
GROUND RESOLUTION fixed, currently the best is around 20m on a system comparable to DMSV (SPOT Multispectral) variable, depending on scale, standard 1:20000 photography has a resolution of approx. 0.5m variable, depending on the flying height, as low as 0.3m. The better the ground resolution, the more data to process
SPECTRAL RESOLUTION fixed, current satellites have between 4 to 7 spectral bands ranging from 0.4 µm to 12.5µm from 0.4µm to 0.7µm, can be extended to 0.8µm using infrared film from 0.4 to 0.8 µm
TEMPORAL RESOLUTION fixed, return time to same site about 16 days, time of day always the same can fly anytime, standard road directory photography is only flown once a year, in summer and it does not include the entire study area can fly anytime
COST OF DATA ACQUISITION 
per 1km2
 between $0.16- 0.80 depending on the sensor and amount of data required approx. $7.30* for colour photography, depending on the number of photographs, their scale and shape of the area (number of runs) approx. $20.80**, depending on ground resolution, size of the area and location
CORRECTIONS 
• radiometric 
• geometric 
• atmospheric 
• hot spot 
• histogram matching

• desirable 
• provided by the supplier 
• desirable 
• not relevant 
• not relevant, unless more than one image used

 any of these correction are only relevant if the photography is to be scanned • desirable 
• desirable 
• desirable 
• desirable 
• desirable
GEO-REFERENCING desirable not relevant  desirable, very time consuming
MOSAICING  usually unnecessary, because single image covers between 60x60 km to 180x180km on the ground unnecessary if only used for photointerpretation and map compilation essential and very time consuming
 
        * cost estimate assumes 25% endlap, 0% sidelap, 1:10000 scale, 5 runs of 90 frames, colour photographs.
        ** cost of acquiring data of current study was used to calculate this figure, assuming 25% endlap 0% sidelap