Auto-find best transformation method.

STHSTH Global Mapper UserPosts: 434Trusted User
edited November 2007 in Projection Questions
I wonder if it is possible to make an algorithm to create the best parameters for transformation between two datums.

I have two files with the same road- network defined. However the transformation method between them is unknown. Lets say WGS84/UTM32 and GRS80/NGO1.

I would like to define the correct coordinate systems. And then do some matching to find the correct transformation method. After finding the best parameters I would like to save them, and do the same on Raster-files.

ER_Mapper does it by using parameters within the bursawol.dat file - containing information like:
datum_change_name
translation_x
translation_y
translation_z
rotation_x
rotation_y
rotation_z
scale_change

(length_id,angle_id,usearea_id)

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited November 2007
    You can add custom datum transformations using the Add Datum button on the Projection tab of the Configuration dialog, but I do not know the algorithm used to calculate tranformation parameters from a series of known points.

    If you are working in a relatively small area, you might just calculate the average shift in X/Y of your data, then just drag your data by that amount so that it overlays your other data.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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