Big yellow collar on georectified tiff

SyrettSyrett Global Mapper UserPosts: 31Trusted User
edited November 2008 in Technical Support
I created a tiff from one of my vector maps, georectified the tiff, and saved it out as a geotiff. I thought the big yellow collar around it was just part of the Global Mapper display window, but when I exported the image as tiles to Google Maps, I found that the collar came along for the ride! Screenshot: http://www.mapgraphics.net/downloads/GoogleFargo1.jpg

Is there some way, when georectifying the tiff (which had no yellow collar), to prevent the creation of anything outside the original image?

Thanks!
Charles

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited June 2008
    Charles,

    You need to check the box to make background pixels transparent when you export your file to GeoTIFF. Otherwise the background pixels used to fill the image out to a rectangle will not automatically be transparent. Since you already have an existing GeoTIFF without the transparency, I would suggest opening the Control Center, selecting the layer, pressing Options, then setting up a transparent color to get rid of the background pixels.

    When exporting to Google Maps, make sure to choose the PNG format so that the transparent pixels will stay transparent as the JPG format does not support transparency.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • kimokimo Global Mapper User Posts: 6
    edited November 2008
    I can see the tick box for 24 bit Geotiff images, but its disabled for 8 bit. What can I do then? If I downsize to a smaller palette in an image package I will lose the geo tags.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited November 2008
    There is not support for an alpha channel for transparency when generating 8-bit GeoTIFF files. You could maybe instead export to a PNG file and choose to generate world and PRJ files as well. The PNG format will support transparency in any configuration.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
Sign In or Register to comment.