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GEOSTATS: are there geodetic reference coordinates at regional level

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  • Andrew Lister
    Dear List, I m wondering if anyone is aware of a gis or other dataset of exact (surveyed) locations of major road intersections, etc. that might be used to
    Message 1 of 2 , Sep 29, 1999
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      Dear List,
       
      I'm wondering if anyone is aware of a gis or other dataset of "exact" (surveyed) locations of major road intersections, etc. that might be used to check the georeferencing of regional datasets, satellite imagery, etc.  It seems to me that we put a lot of faith in these satellite images, etc., hoping that whoever did the work really georeferenced them with the standards they describe. 
       
      Does anyone have any other suggestions for how to address this problem?
       
      Thank you,
       
      Andrew Lister
      US Forest Service
       
       
    • Heinz Burger
      ... Hello Andrew, to our experience georeferenced satellite images don t offer additional advantages: a) Not all software packages can handle the specified
      Message 2 of 2 , Sep 30, 1999
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        Andrew Lister wrote:

        > Dear List, I'm wondering if anyone is aware of a gis or other dataset
        > of "exact" (surveyed) locations of major road intersections, etc. that
        > might be used to check the georeferencing of regional datasets,
        > satellite imagery, etc. It seems to me that we put a lot of faith in
        > these satellite images, etc., hoping that whoever did the work really
        > georeferenced them with the standards they describe.

        Hello Andrew,
        to our experience georeferenced satellite images don't offer
        additional advantages:
        a) Not all software packages can handle the specified projection
        b) geometrical correction based on GPS (or map) reference points
        was more accurate (in our test).
        c) you will get a better idea about the positional accuracy (depending
        on
        the reference accuracy) if you do the job yourself.
        d) About standards, geodetic reference coordinates and ...:
        "Vertrauen ist gut, Kontrolle ist besser" (Lenin)

        Regards,
        Heinz Burger
        --
        *****************************************************
        Dr. Heinz Burger
        Freie Universitaet Berlin
        - Geoinformatik -
        Malteserstr. 74-100
        12249 BERLIN, Germany
        Tel. (49) 30-7792-561 Fax: (49) 30-775-2075
        e-mail: hburger@...-berlin.de
        Web-Seite: http://userpage.fu-berlin.de/~hburger
        ****************************************************


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