DATUM: Pulkovo 1942 @v.9 vs S-42 (Pulkovo 1942) @v.11.02

stkornstkorn Global Mapper UserPosts: 9
edited March 2013 in Projection Questions
I have one QuickBird raster. Also I have one point of crossroads at them.
Raster is geo.tiff with projection: UTM, 37 zone, WGS84, METERS.

I open this geo.tiff file in GlobalMapper9 on workspace:
GuassKrueger (6 degree zones), Zone 7, Datum PULKOVO 1942, METERS.
Crossroads has coordinates (from statusbar): GK6 (PULK42) 7530415.245, 5841441.372 ~ 52°42'00.27''N 39°26'59.69''E

I open this geo.tiff file in GlobalMapper11.02 on workspace:
GuassKrueger (6 degree zones), Zone 7, Datum S-42 (PULKOVO 1942), METERS.
Crossroads has coordinates (from statusbar): GK6 (S-42) 7530430.376, 5841415.732 ~ 52°41'59.4424''N 39°27'0.4846''E
Use datum S-42 (RUSSIA) got some results.

Difference is ~ 1'' or ~15-30 meters.

When I used in both version of GlobalMapper workspaces with projection:
GuassKrueger (6 degree zones), Zone 7, WGS84, METERS
I have got same results in both version:
7530296.603 5841331.644 52°42'00.07'' 39°26'53.39''

So, Datums Pulkovo 1942 @v.9 and S-42 (Pulkovo 1942) @v.11.02 are different. But which is true?

How I can give on v.11.02 same projection as v.9?

Thank you very much!

Comments

  • stkornstkorn Global Mapper User Posts: 9
    edited May 2010
    Russian soft "GIS Panorama" www.gisinfo.net sayd, that:
    WGS84 - 52°42'00.07'' 39°26'53.39''
    is is equal than 52°42'00.27''N 39°26'59.69''E on Pulkovo 1942,
    and 7530415.245, 5841441.372 on GuassKrueger Zone 7.

    So, Pulkovo datum @GloabalMapper v.9 is more correct than v.11.02

    Please, help me - I need the v.11 features!
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited May 2010
    I think what is happening is that in v10.00 the base S-42 (Pulkovo 1942) datum was updated to automatically use the best S-42 specialization based on the lat/lon location being transformed rather than using the base S-42 transformation that is not very accurate for many locations. For your particular sample location, the S-42 (Russia) transformation would be used which is slightly different. So you should actually be getting a more accurate transformation in v11.02 for the base S-42 (Pulkovo 1942) than you were in other versions. I'm guessing the other software is just using the base S-42 transformation and not a specialized one with better parameters for your local area.

    Can you try using the S-42 (Russia) transformation in v9 and see if you then get the same results that you are seeing in v11.02?

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • stkornstkorn Global Mapper User Posts: 9
    edited May 2010
    Unfortunately, my vector map was drawed on raster map, generated on old v9 PULKOVO 1942 datum.

    Now, when I do export raster data from v11.02, where are essential displacement between raster and vector. 30 meter is very long distance for mistakes.

    How I can export raster data from v11.02 in older, same as in v9, PULKOVO 1942 datum?

    Can I add custom datum with any parameters for emulation old v9 PULKOVO datum? What values of datum parameters I need to use? Need I add custom ellipsoid?
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited May 2010
    What you can do is create a custom datum based on the existing Krassovsky ellipsoid with the following 3 parameters:

    DX: 28
    DY: -130
    DZ: -95

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • stkornstkorn Global Mapper User Posts: 9
    edited May 2010
    Thanks, it work!
  • JustinKJustinK Global Mapper User Posts: 11Trusted User
    edited March 2013
    Mike,
    I am having problems rectifying scanned maps In Poland. Maps were from the late 1970s to 1985. I assume it is System 1942 --> From http://gpsinformation.info/main/warsaw.txt it says "Topographical maps based on "military" maps, typically in 1:100000 scale (also 1:50000 - 1:200000). ...As usually, they do not specify on the map which system it uses, but it is clear that they use S-42 (Pulkovo 1942) together with the Krassovsky 1940 ellipsoid …

    The maps are off on the order of -300 to -400m in both x and y. I have one scanned map in zone 3 and one in zone 4.


    I am using this

    CurrentDatum.jpg

    I tried both zones, 3 and 4.


    I came across a list of Polish datums that includes additional shifted 1942 datums… they are in the zip file located here à http://www.npgc.pl/wp-content/uploads/2011/02/pl_ukl_wsp.zip?
    ShiftedDatums.jpg

    Do these make a big difference in the 1942 grid? Im just guessing that this may be why I can’t line this map up.

    Can you add these shifted datums to 13.2?

    Thanks

    Justin
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2013
    Justin,

    We won't be adding any new built-in datums to v13, but you can add a new custom datum for that. See http://www.georepository.com/transformation_1644/Pulkovo-1942-58-to-ETRS89-1.html for the transformation to use when defining the new custom datum.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.bluemarblegeo.com/
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