Troubles georeferencing maps using UTM projection

corina
corina Global Mapper User
edited November 2009 in Georeferencing Imagery Discussion
Hello everyone,
For cuple of days i'm trying to georeference some maps using UTM projection, datum WGS 84, zone 35 north hemisphere. I select the corner of the map in the "zoomd view" and click there with the mouse and then i put the coordinates indicated in the ground control point next to the x/Esting/Long, y/Northing/Lat. I proceded this way with the 4 corners of the map. But map turs out to be up side down and in mirror position. I don't understand wher is the problem? Could anyone help me?

Corina

Comments

  • global_mapper
    global_mapper Administrator
    edited November 2009
    When you are entering your lat/lon coordinates, make sure that you enter negative values for any longitudes in the Western hemisphere and latitudes in the Southern hemisphere. Not doing that would cause the image to flip.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • corina
    corina Global Mapper User
    edited November 2009
    I think i solved the problem. Initialy i thought i must write in meters the coordinates. That's why i wrote the x and y shown in "gound control point" in stead of the lat and long shown on the scanned map. I did not know global mapper will transform the lat and long of the point selected in the "zoomed view" in meters for me.
    But i still need the confirmation that what i did is the wright way to georeference maps using UTM projection, datum WGS84 zone 35 (north hemipheare).:D

    Corina
  • global_mapper
    global_mapper Administrator
    edited November 2009
    Corina,

    When rectifying to a projected system (like UTM) you can either enter the meters easting and northing values (if known), or enter lat/lon values and have GM automatically convert them for you. Both methods should work fine, although it is more common to know the lat/lon locations vs. the meters easting/northing values.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com

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