I don't have any formal education in GIS so I'm thinking that I'm looking for something that exists, I just don't know what it's called.

I basically have a large raster data set that will get re-sampled into a pyramid of various resolutions (1m, 2m, 4m, 8m, etc) Is there a way to generate the pyramid with gdal using a custom projection?

And once that's created, is there a way to run operations on specific tiles and save them in a new pyramid in an organized way that can be referenced later?

I'll likely have multiple derivatives and will need to be able to check for the existence of a tile in a derivative pyramid, if it's not there, then create it based on the original pyramid. the tiles that get selected from the derivative pyramid would be based on a polygon overlapping an index for the pyramid of some sort.

I hope this makes sense. If this is something that I need to build from the ground up, then maybe someone can at least point me in the right direction so I know more about whats already available along these lines.

I should also mention that the derivative tiles will be made up of data of a dataset with tiles of different boundaries. (Such as combining a hillshade with aerial imagery) all the pyramids will all need to be built with tiles of exact same boundaries as the original dataset.

  • 1
    There is GDALAddO gdal.org/gdaladdo.html which will pyramid the files in a way that most GIS software will understand. It sounds like you want create reduced resolution rasters instead (not true pyramids), you can use GDAL_Translate with -outsize 50% (double pixel size) then -outsize 25% (4 x pixel size) etc.. until you have a set of reduced resolution rasters. – Michael Stimson Aug 8 '18 at 6:33
  • A tiled BigTIFF file with internal overviews created with gdaladdo is quite close what you want and GDAL supports it well. Also because you are familiar with JPEG 2000 you could stay in that format and read data with some of the most effective drivers, like JP2KAK. – user30184 Aug 8 '18 at 6:53
  • I do need to create reduced resolution tiles but they need to be based on an exact tiling system based on the lowrance mercator meter projection. each tile edge must land right on the meter. The tiles will need to be stored in individual files rather than in a BigTiff or similar and will need to be in PNG or GEOTiff format for compatibility with some external conversion software. Can someone explain what a true pyramid is and how it compares to what I'm doing? – Steven Lutz Aug 8 '18 at 7:07
  • it looks like gdaladdo keeps the data in one file. I need the downsampled versions to be in separate files. gdal_translate looks like it could be an option as long as I can figure out a way to make sure the datasets are on the same grid. I basically want to generate a pyramid of a large area (say of an entire country) but only process the data that I need at the moment if it hasn't been generated yet. When I start needing data that is next to data that is already processed, I can't have overlapping tiles. Ideally I'd like to have. I hope this makes sense – Steven Lutz Aug 22 '18 at 2:33

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