Global Mapper v25.0

Openig tiff files

Celina
Celina Global Mapper User
edited February 2009 in Technical Support
hi, i have toposheets of an area that i would like to merge or append to have it as one, so that i can overlay my study area. when open them in ARCGIS,they are georeferenced UTM WGS84 zone 34S. problem is when i open them in global mapper 9.0, it says the data does not have spatial reference.

i donot know how to use global mapper, but someone told me i can export to TWF or something like that,
please help.
thank you,
Celina.

Comments

  • global_mapper
    global_mapper Administrator
    edited February 2009
    Celina,

    What format is your original data in?

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Celina
    Celina Global Mapper User
    edited February 2009
    hi,
    my data is scanned toposheets saved as tiff.
    thank you,
    celina.
  • global_mapper
    global_mapper Administrator
    edited February 2009
    Celina,

    You can load your data using the File->Open Data File menu command. When you do that are you just being prompted to enter a projection (in which case you would select UTM with a zone of -34 and the WGS84 datum), or are you being prompted to rectify the imagery? If it is the latter then the file does not contain any spatial information for Global Mapper to place it. Can you generate a TFW file or something from ArcGIS for your file so that Global Mapper can properly place it?

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Celina
    Celina Global Mapper User
    edited February 2009
    Mike,
    you are right, thats what happening to me but i don't think i can generate TFW from ArcGIS, i know of a prj but raster data do not come with it after exporting. how do i refresh my workspace? because i can remember at first it straight asked me for projections but i couldn't finish because i had to go somewhere.

    thank you,
    Celina.
  • global_mapper
    global_mapper Administrator
    edited February 2009
    Celina,

    You can close the TIFF file if you already have it open by opening the Control Center, then selecting the TIFF layer and pressing the Close button. Or you could just use the File->Unload All menu command. Then just use the File->Open Data File menu command to load the TIFF again.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Celina
    Celina Global Mapper User
    edited February 2009
    Mike,

    thank you for your help, i will try later again. i just find out that this data have TFW files anyway but still global mapper can not recognise it....i will try later anyway.
    thank you!
    celina.
  • global_mapper
    global_mapper Administrator
    edited February 2009
    Celina,

    The TFW files just contain the mapping from pixel coordinates to some projection system, so if the TIFF file itself doesn't contain projection information and you don't have a PRJ file, you will still have to select the projection for the file.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com