why there is a sharp terrain scenery

geo-data / cesium-terrain-builder

A C++ library and associated command line tools designed to create terrain tiles for use in the Cesium JavaScript library

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why there is a sharp terrain scenery #33

Open mingweiLIU opened 8 years ago

mingweiLIU commented 8 years ago

Hi. I have built CTB by Visual Studio 2015 with GDAL2.0.1, then use CTBtile to tile my DEM data with command -o XXX XXX.tif. The tool worked great while it appears a sharp scenery in CesiumJS which is not that much smooth with it in arcglobe, I am not talking about the sharp boundary but the area with some real data such as a hill will look like a pyramid. The original data is in WGS84 coordinate. I don't know if there are some restraints for input data such as supposed bits or there are something else I have left out? qq 20151201224249

dg3feiko commented 8 years ago

My case is like this, the edges are spikes

mrgloom commented 7 years ago

@dg3feiko I have such problem when zero values in DEM were not equal to zero.

mingweiLIU commented 7 years ago

Thanks for reply. yes, it is, especially at the eage of each raster. This could be fixed through raster calculator in ArcToolbox.

helmi03 commented 7 years ago

I use http://www.gdal.org/gdal_fillnodata.html

gaolizhou commented 7 years ago

@helmi03 could you share the details. It seems lots of guys suffers from this issue.

helmi03 commented 7 years ago

For my use case, I only interested with data above sea level. I have same 'spike' issue as @dg3feiko , and found out error caused by DEM value < 0, same as mentioned by @mrgloom.

My first try, reprocess the geotiff with http://www.gdal.org/gdal_fillnodata.html. But have issue with nodata on sea surface.

Since I don't care below sea level, reprocessed the geotiff using "set values of zero and below to null" as http://www.gdal.org/gdal_calc.html

mrgloom commented 7 years ago

Is there any smart way to process DEM with no-value and zero values (not setting no-value to zero)?

emrebayramc commented 7 years ago

I have a fix for this problem: https://github.com/geo-data/cesium-terrain-builder/pull/49

mrgloom commented 7 years ago

Before my DEM.tif have NoData Value=0 and now NoData Value=-100 and it doesn't work.

@helmi03 gdal_fillnodata.py DEM.tif DEM_2.tif not hepled, can you specify full example? Also maybe with gdalinfo before and after applying gdal_fillnodata.py?

@kazanture How to apply this fix? Just git clone https://github.com/kazanture/cesium-terrain-builder ?

emrebayramc commented 7 years ago

The best way is the repo owner to accept my pull request. Until that time you can either clone my fork or apply my small fix manually.

ajinra020307 commented 3 years ago

My case is like this, the edges are spikes

iam having this same issue, did you find any fix?