Anybody have a good way to strip out a band to make an aerial work normally in CAD? I have access to some awesome 4-band imagery that works much of the time, but there are some issues.
Global Mapper ignores the extra.
QGIS seems OK, it merged some just fine.
C3D works but sometimes shows an almost inverted image -> especially when printing to PDF, the rest of the time it was fine.
Thanks, Thadd
What happens if you export a geo-tif from Globalmapper, and import that to CAD?
Good thought. I have not tried that one.
The imagery is very close to surveyed data. But it is HUGE.
GM lets you window out a smaller portion of the loaded data for export....
Thank you for teaching me how to use the program in my computer. GM Rocks.
Did GM take care of your problem?
I've used 4-band imagery for 20+ years. The usual order of bands was always: Band 1 = Blue, Band 2 = Green, Band 3 = Red and Band 4 = Near Infrared.
I ran into an oddity earlier this year where the band order was RGBIr instead of the normal BGRIr ordering. I've heard that there is an new 4 band format that some imaging software cannot handle. It is similar to CMYK. The newest version(s) of Photoshop can read it and convert to RGB.
Also, AutoCAD has always required the band interleaf to be BIP (Band Interleaved by Pixel) rather than BIL (Band Interleaved by Line) or BSQ (Band Sequential interleaf). ESRI seems to like the BIL format for their products. For image processing tasks the BSQ format is usually the fastest with BIP being slow to very slow.
Does your imagery come with a metadata file (e.g. XML file)? If so, I'd be happy to take a look. Forward it to kooper8151 at comcast dot net.
Yes, GM took care of the issue.
CAD was saddened by the image. The image would bleach away here and there, especially on a DWG to PDF plot. It would print fine to a printer.
The meta is likely in the download in xml, but I am on a laptop. Here is a link to the data copied into a TXT.
Thanks Thad,
I don't see much information in the metadata file. It is mostly generic boilerplat for the USGS High Resolution Orthoimagery. All I found that was specific to the tile were the bounding latitudes and longitudes. The information does indicate that 4-band imagery is visible and near infrared so GM will handle that okay.
I haven't upgraded GM since Ver. 13, but when I load a 4-band GeoTIFF file it asks whether the additional band is an alpha (transparency) channel or and additional band of data (like infrared). Selecting the extra band of imagery data then loads an RGB file which can be exported as a 3-band GeoTIFF.
If the color seems a bit off, it may be that the bands are ordered as BGR and GM is assuming that it should be RGB. If you want to send a small sample I can check the band order.
