High Resolution 1:10,000 scale Mapping Strategy of Multi ... - NDMA

1:10,000 0.25 m 2.5 m
1:16,000 0.25 m 2.5 m
1:20,000 0.25 m 10.0
Table 9.4: Comparison of GSD for Satellite imagery and aerial photography
A target scale of 1:6000 and less is not possible with resolution 0.5 m as
some of the finer features like poles, manholes will not be visible on these satellite
images and therefore for such map scales Aerial imagery is used. With the present
commercial stereo satellite imagery available a target scale of 1:7,000 or more is
possible. (For more details please refer to Annex. XVII)
� The accuracy achieved for Geoeye test data, shows that the map scale of
1:7,000 and above is achievable as per ASPRS standards reference (Table)
for aerial images, but the problem lies with the GSD of the satellite Data, for
Geoeye has a GSD of 0.5m
� QuickBird is limited to 6,900 lines/second with orbit speed 7,638m/sec and
footprint speed 7,134m/sec - with 0.62m GSD slow down factor 1.61 required
� EROS-B – 2,400 lines/sec � slow down factor at least 4.2.
� EROS-A – 750 lines/sec � slow down factor at least 5.2 limiting imaging
capacity, with EROS only individual areas, no large continuous coverage
Important also is the internal storage and downlink capacity.
Satellite Collection rate Approximate theoretical collection
capacity / day
IKONOS 2,365 km²/min 150,000 km²/day
QuickBird 2,666 km²/min 135,000 km²/day
OrbView-3 1,483 km²/min 80,000 km²/day
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