Applicable plans
Lake Valley Mountain Peak


You have created a terrain but you see high "walls" around the edges. You want to remove these walls.



Background


GeoTIFF files are always represented as a rectangle but when you capture your terrain with a drone you will typically not end up with a rectangular shape. That is why the GeoTIFF format allows you to specify a NoData value to fill the area between your captured terrain and the border of the image. The pixels with this value can be safely ignored. Most softwares that create GeoTIFF files will automatically set this NoData value to a large negative number (e.g. -10 000, -99 999, ...). 


If a NoData value has been provided correctly, Virtual Surveyor will recognize it and will replace it with a background value. The background is automatically suggested by Virtual Surveyor. It will be a value close to the lowest point of your terrain. 


If your GeoTIFF is not "clean", a wrong NoData value can be read and it might lead to a situation as shown in the image above where you see steep edges in your project. This can happen because one of the following reasons:

  • The NoData value that is provided in the GeoTIFF header is not correct;
  • There are multiple NoData values (e.g. because of a reprojection of the data);
  • The data has been preprocessed in such a way that the edges have been modified (e.g. because of smoothing or a lossy compression algorithm)


Quick Guide


You need to recreate your terrain and should manually set an Ignore value and then click "Suggest" again. 


You would typically set the Ignore value smaller or equal to an elevation close to the lowest point of your terrain. If you don't know the lowest elevation, we recommend that you set the Ignore value to "<= 0".