Geography Reference
In-Depth Information
good geometry and it was habitual to use the panchromatic band of that sensor (HRVIR) in
scales 1:25.000 and 1:50.000.
The orthorectification of the panchromatic band (in fact it covers the red band - 0.61 to
0.68µm), with a 10 m spatial resolution, was carried out with Orthoengine 9.0, by PCI
Geomatics, using 7 GCPs and SRTM DEM.
The assessment used 7 points, whose coordinates were determined by relative static
positioning (likewise as for the GCPs), with single frequency GNSS trackers.
The study area was also the same used in the assessment of the Landsat Orthoimage and
corresponds to part of the municipality of Angra dos Reis, Rio de Janeiro, Southeast Brazil.
The results
suggest
that the Orthoimage presents an accuracy compatible with the
Class A
for 1:50,000 scale
or
Class C for 1:25.000 scale
, since all points presented errors up to 20.5 m
and SD of 7.4 metros. Likewise as in the Landsat assessment, the use of a small amount of
points in the assessment does not allow to surely warrant the accuracy, but it is an indicator
of its quality in terms of geometry.
Finalizing this part of the chapter, we present a summary table (table 3) with results
from the accuracy assessments in terms of geometry for each of the sensor products
analyzed:
Sensor
Product
Scale
Classe/PEC
Orthophoto
1:2.000
Class A
LIDAR
MDT
1:2.000
Class B
MDS
1:5.000
Class C
Orthoimage
1:2.000
Class B
Geoeye-1
DEM
1:10.000
Class C
Orthoimage
1:2.000
Class C
IKONOS-2
DEM
1:10.000
Class C
Orthoimage
1:10.000
Class B
CARTOSAT-1
DEM
1:25.000
Class A
Orthoimage
1:25.000
Class A
ALOS / PRISM
DEM
1:25.000
Class A
ALOS / AVNIR
Orthoimage
1:50.000
Class A
Orthoimage
1:50.000
Class B
ASTER / VNIR
DEM
1:50.000
Class C
Version 1
1:50.000
Class C
Version 2
1:50.000
Class C
SRTM (DEM)
Version 4
1:50.000
Class C
Topodata
1:100.000
Class A
SPOT 4 / HRVIR: Pan
Orthoimage
1:50.000
Class A
Landsat 7 / ETM+ / Multiespectral Band
Orthoimage
1:100.000
Class B
Table 3.
Summary results of the assessments
