Changes between Version 1 and Version 2 of Processing/NetworkAdjustment


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Timestamp:
Jun 10, 2008 4:22:44 PM (12 years ago)
Author:
benj
Comment:

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  • Processing/NetworkAdjustment

    v1 v2  
    33334. For network adjustment you should only have one ground control point (permanent base station) selected, at least initially. Pick the ground control point that you think will give you the best results, and for all the others right-click on them and select "Toggle between Control/Check".
    3434
    35 5. Select Process > Network Adjustment. Leave all settings as default and click Process. A text file with the results will be displayed. Check it as below:
     355. Select Process > Network Adjustment. Leave all settings as default and click Process. If you get an error saying you have a hanging station, you have at least one base station that does not have any green (success) lines connecting it to a control point - go back, find it and make at least one of its connecting lines green as above. Otherwise, a text file with the results will be displayed. Check it as below:
    3636
    3737    5.1. Scroll down to the "Output Vector Residuals" section. RE, RN, RH, PPM and STD should all be small (these are measures of error). The most useful seems to be PPM, which is the Parts Per Million error relative to the length of the baseline (ie 1PPM equates to an error of 1cm on a baseline of 10km). Any entry marked with a $ symbol should be regarded as unacceptably large - you probably have a setup problem. When I got this, it was caused by the fact that I had three base stations in different places with the same name, and !GrafNet had tried to put them all in the same place (causing a 400km positioning error when the distances were checked) - go back and change station names if appropriate, or find whatever else you've done wrong or where your data is bad.