Importing .tif images
bdavenport
Global Mapper User
I am attempting to work with band ratios I produced from Worldview 2 data in Global Mapper, but they default to importing as DEMs (the 'DEM or image' dialog does not appear) and the values are flattened and the detail of the image is lost. If I try to go back to the original bands themselves, the values are flattened beyond utility as well. Layerstacking these images (my next step in order to drape them over a DEM) produces nonsense.
1) Is there any where to force global mapper into the 'DEM or image' dialog if it doesn't not autoprompt?
2) If it's just a visualization issue rather than an error in reading the values in the raster grid, I would assume tweaking the shader would help but switching to a color ramp shader either makes things worse or leaves them the same
Any insight into these problems would be greatly appreciated!
1) Is there any where to force global mapper into the 'DEM or image' dialog if it doesn't not autoprompt?
2) If it's just a visualization issue rather than an error in reading the values in the raster grid, I would assume tweaking the shader would help but switching to a color ramp shader either makes things worse or leaves them the same
Any insight into these problems would be greatly appreciated!
Comments
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Hello bdavenport,
Can you furnish a data sample, so we can test the issue on our end? What version of Global Mapper are you using?
You may attach the sample to this thread, email Application Support at geohelp@bluemarblegeo.com with the sample as an attachment or to inquire after login information to upload the data to the Blue Marble FTP site.
Regards,
Jasmine Bird
Blue Marble Application Support -
Hi Jasmine,
Thank you for your reply. Unfortunately each of the files in question are over a gigabyte in size, so I do not believe uploading them is tenable. I have attached images of the same file open in ArcDesktop and Global Mapper - the metadata in both still reads them as 32 bit floating point, 2 m pixels, et c. and so I still believe the issue is that Global Mapper believes that the raster is a DEM (metadata gives the elevation as .006-46 m in GM, which corresponds to the radiance values for the band). I am using Global Mapper 15/64 bit.
Thanks!
Bryce -
Hi Bryce,
Based on your description, it does look like Global Mapper is recognizing the radiance values as elevation values. Are you exporting the file as a GeoTIFF from Arc?
Can you crop the data and export it so we can look at a sample? You may do this from Global Mapper by going to File > Export Raster > Select Format and then if you go to 'Export Bounds' and select the 'Draw a box' option to limit the area, and thus the file size, of the export.
From ArcGIS, there should be a similar option in the Export Raster Data dialog box. If you could export a clip from ArcGIS to the format you are using, as well, that would be great.
Regards,
Jasmine Bird
Application Support Specialist
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Hi Jasmine,
I have clipped the image in both Global Mapper and Arc and asked the geohelp staff for FTP access; the images are coming to me from Digital Globe in GeoTIFF and I've maintained that format throughout.
Thanks!
Bryce
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