Plotting to PDF GeoReferencing - uStn V8iSS4

We are needing to add some 'accuracy' disclaimers to our GeoReferenced PDF that we are creating from uStn.

All of our models are setup with the appropriate Local Projection Coordinates, and these are magically 'transformed' into the Lat/Long coordinates used in the resulting PDF files.

It is this 'transformation' that we need to know how this is performed (eg. crude move/rotation/scale, a more accurate 7 parameters transformation, or an unlikely but most accurate Grid Shift transformation) and what degree of accuracy we can expect over various spatial extents.

Fundamentally, the accuracy of the devices (phones/tablets) used onsite are likely to be the determining factor in the degree of accuracy, but obviously the 'correctness' of the data itself is the first point in determining that.

  • try this create  a new file  set your geo to long lat, now ref attach the dgn that you used to create the geopdf, make sure the source dgn has the same boundary you used to plot to pdf...

    Now ref attach your  pdf  through the raster manager  and  see if it  lands exactly.. measure the  coordinates of each corner point  in long lat and write them down

    Now return to your original dgn measure the coordinates of each corner  of your plot boundary  and write them down and ref attach your  long lat pdf through the raster manager  make sure in both trials you allow the  program to repoject now does this land in exact place measure the points ...

    if you have access ( maybe on line) to convert long lat coords to you  local datum and  input the recorded values  and  compare with the real values inside the pdf if you open the pdf with viewer and see coordinates listed...

    Repeat with  original data NE and convert to long lats and compare your results... you should be able to determine how accurate stuff as stayed...

    other wise give your results to a surveyor and ask him to transform your  points from EN to LL and  your measured LL in the pdf  and compare the out puts both ways...

    Lorys

    Started msnt work 1990 - Retired  Nov 2022 ( oh boy am I old )

    But was long time user V8iss10 (8.11.09.919) dabbler CE  update 16 (10.16.00.80) 

    MicroStation user since 1990 Melbourne Australia.
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