[pdal] GDAL Writer artifacts along edge of tile

[Lars]

Andrew,

Thanks for the excellent feedback. We'll experiment with increasing the size of the raster and cropping it.

kind regards, Lars

________________________________
Fra: Andrew Bell <andrew.bell.ia at gmail.com>
Sendt: mandag 13. august 2018 15.32
Til: Lars
Kopi: pdal at lists.osgeo.org
Emne: Re: [pdal] GDAL Writer artifacts along edge of tile

Hi,

I'm not sure that there's enough information here for me to help you.  You'll have to be specific about how the counts are different than you expect, how you're creating your tiles and reassembling them.  Keep in mind that points outside the provided bounds aren't considered when making the raster.  This typically means that some points that would be considered as contributing to a cell will get discarded when that cell is on the edge of the raster.  You're probably better off making the bounds one cell larger than you need (depending on the radius argument), and then trimming those edge cells away with GDAL or some such.  This is behavior that could be changed, but I believe that when I wrote the code, I was trying to keep it consistent with points2grid, which was the software that PDAL originally used to create rasters.

Hope that helps,


On Mon, Aug 13, 2018 at 8:15 AM, Lars <laasunde at hotmail.com<mailto:laasunde at hotmail.com>> wrote:
Hello,


We have created a pipeline using pgpointcloud reader and gdal writer (see attached file).


Using the pipeline to create a full raster for an area works great. However if we tile the same area we are seeing some 'artifacts' along the edge of the raster (band 5, Count). The count is different along the edges of the tiled raster compared with a full raster (see attached screenshot taken from QGis showing band 5 of rasters).


We use the 'where' option in the reader.pgpointcloud to provide points that is writer.gdal.bounds + margin.


We would like to know why these 'artifacts' occur and how to prevent them from happening?


kind regards, Lars


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Andrew Bell
andrew.bell.ia at gmail.com<mailto:andrew.bell.ia at gmail.com>
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