Global Mapper v25.0

background color when exporting

kalden
kalden Global Mapper User
edited November 2011 in Raster Data
I am georeferencing some image files into a UTM projection. After georeferencing, the source image is skewed a bit, with the current background color used to make the image square.

Is there anyway to make this background color transparent? When I display a high res map over a low res map, I would rather see the low res imagery than dead pixels from the high res file.

Thanks

Comments

  • global_mapper
    global_mapper Administrator
    edited March 2010
    Are you exporting the files after geo-referencing or just keeping them in the main map view? I would expect the border to be added when exporting if the image is not rectangular in the export projection. You can have this marked as transparency for some formats though, like GeoTIFF, ECW, JPEG2000, or PNG. If you are just referencing into the main view I would not expect any additional pixels to be added.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • kalden
    kalden Global Mapper User
    edited March 2010
    I am exporting into a geotiff file. How do I mark the additional pixel data transparent?
  • global_mapper
    global_mapper Administrator
    edited March 2010
    If you are exporting using the File->Export Raster->Export GeoTIFF menu command there is an option to check to make the background pixels transparent.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Miguel
    Miguel Global Mapper User
    edited June 2011
    Hi Mike,
    We have a similar problem, we have a 4 band image, and when we cut the image and export it we have data in black, we check the option to make the additional data transparent but that generates another band in the image, and we end up having a 5 band image.
    All the transparent data goes to the 5th band.
    Can you help us.
  • global_mapper
    global_mapper Administrator
    edited June 2011
    You have to add an additional band for the alpha channel in order to mark some of the pixels as transparent. You still have 4 data bands in the output, then an additional alpha channel band used to indicate pixel validity. There really isn't a way around though if you need to have pixels marked as invalid.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • vasquezt
    vasquezt Global Mapper User
    edited November 2011
    If you are exporting using the File->Export Raster->Export GeoTIFF menu command there is an option to check to make the background pixels transparent.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com

    I have the same problem. I've been exporting as a JPG, which doesn't even give you this option, instead of JPG2000. However, if I check the box to make the background pixels transparent, I can't view them in ArcView. If I don't check the box to make the background pixels transparent, I can view them in ArcView.
  • global_mapper
    global_mapper Administrator
    edited November 2011
    The JPG format doesn't support transparency. The JPG2000 format does support an alpha channel, but not all applications support JPG2000 files with transparency (like apparently your version of ArcView). Can you use GeoTIFF? The alpha there is more widely supported, although the files are obviously larger, but you can use JPG-in-TIFF compression with a GeoTIFF.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • Tai
    Tai Global Mapper User
    Hi 
    I imported GeoTiff images (with background pixels) and tried to export PNG with background pixel transparent in batch converter. The PNG images still have a black background pixels... Can anyone please help with this?
    Thank you in advance 
    Tai
  • bmg_bob
    bmg_bob Global Mapper Programmer
    What version of Global Mapper are you using?  Did you try the same export from the main UI instead of the batch converter?  If so, did it work?