2 weeks ago
I have a problem with new pyramid format .pyrx.
PYRX format is great when it comes on saving memory space.
But after pyramid generation on a 16-bit image through Edit Image Metadata function, I get black pixels around my image (Image1.png).
When I set nodata value for the image, I get black pixels across whole footprint of the image (Image2.png).
Then I deleted pyramid layers and computed them again several times, choosing every time different downsampling method.
I got black pixels everytime except for SIPS resampling method and ErdasBino3.
Do anyone know is this a bug with .pyrx format or I have to choose one of these methods everytime when I compute pyramids?
Also, is there an explanation of downsampling methods?
This doesn't happen when pyramids are computed through some other function (like LUT stretch).
Solved! Go to Solution.
2 weeks ago - last edited 2 weeks ago
The downsampling methods are explained in the Help for the Create Image Pyramids operator (which should also be linked to from ImageInfo and Image Command Tool Help pages):
Make sure you define the correct NoData for your imagery prior to generating PYRX format pyramids. PYRX uses ECW compression and so is lossy and so you run the risk of turning 0s into non-0s if you haven't defined a NoData mask to be used during the compression process. Your data may not use a value of 0 of course, so pick the correct NoData approach for your data.
By the way - if you decide PYRX isn't the correct pyramid format to use for your purposes then you can set the Preference editor > File Formats > Image Files (General) > Pyramid Layer Generator option to produce RRDs instead (the old format of pyramids). Or you can always pick the Generator method when running ImageInfo, Image Command Tool, or Raster Output in Spatial Model Editor.
Hope this helps.