PHOTOMOD VectOr (raster images processing) - Racurs

PHOTOMOD
b). If there is no GCP catalog available you can use 2 steps transformation (see
chapter 3.3):
• Select on the vector map two points at a maximum distance. Both of them
should be precisely recognizable on the raster image.
• Complete a first step of the transformation.
• If you are satisfied with the results of the first step stop processing.
Otherwise you should go to the second transformation step. Select well
distinctive terrain features as control points. Note that all of them have to be
time independent (especially in case of a big time difference between a
raster image and a vector map). Thus don’t use as control points such terrain
features as a forest corner or a river’s crook. Roads intersection (close to
right angle) or building’s corner are preferable.
4. Rules of creating GCP coordinates catalog.
The catalog of GCPs coordinates may contain either rectangular coordinates in
Pulkovo 1942 coordinate system (Gauss-Kruger) or geodetic coordinates (degrees,
minutes, seconds). Besides there are some additional records to be added to the
catalog in case of the transformation, using exterior orientation parameters. See for
details appendices 1,2,3.
5. Creation of the passport of a digital map.
5.1. General info.
Digital map passport includes general information related to the map sheet (scale,
projection, coordinate system, rectangular and geodetic coordinates of the map cornres, etc.)
To create a map passport go to “File | New | Map” menu. “Map creation” dialog opens.
You can fill out the dialog fields in two ways:
- copy information from an existing map (Copy)
- enter all necessary information manually (starting from the left part of the dialog)
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