Banding issues causing problems when image is used for HeightField

[Tudor]

Hello Everyone,
I've run into a problem that I wondering if Terragen itself might have a solution for.
The GIS program that I getting the image from to create my terrain is causing banding between the topographical layers.
I can remove/diminish the banding by adding noise to the file but it then causes Terragen to provide me with a non-smooth landscape.
I've also tried converting to 16-bit and slightly blurring the image.  That does not seem solve the problem either.
Is there a solution to this that anyone can think of?
Any help would be greatly appreciated.
Regards,
Tudor

[Hetzen]

What software are you processing your terrain data to get your tile?

It's usually best to export .ter to maintain data integrity. If you need 16 bit tiff,  make sure you're exporting 16 bit at source. Blurring 8 Bit  after converting to 16 bit doesn't get rid of steps.

[AP]

Yes, at least 16bit minimum but if .ter is available definitely go with that format. The stair stepping effect is notorious in 8bit images.

[Tudor]

Th file is coming out of ARC GIS which I believe can't export .ter... but I don't own the software.
Can someone confirm otherwise?

[Tudor]

Apparently ArcGIS does export to .Ter

http://desktop.arcgis.com/en/arcmap/10.3/manage-data/raster-and-images/supported-raster-dataset-file-formats.htm

Thanks for kicking me to double check.

[Oshyan]

Are you doing any editing of the file in ArcGIS, or just using it for file conversion? What format is the original file? Terragen may be able to load it without conversion. It's worth a try.

- Oshyan

[Tudor]

Turns out I was wrong.
ArcGIS can import a .ter file but it can not export a .ter file.

For those that might be interested in this later here is the full list of import and export options currently within ArcGIS.
http://desktop.arcgis.com/en/arcmap/10.3/manage-data/raster-and-images/supported-raster-dataset-file-formats.htm

It also turns out that .png and .jpg can't be exported out of ArcGIS at 16 or 32 bit.

When looking more carefully through the documentation I noted that ArcGIS can export a 16 and 32 bit .tiff file so the person I'm working with at the company that is providing me with the files tried that.  The base tiff file (8-bit) came in very blocky (their original data is at a 1 meter resolution) but when she exported it at 32-bit the file was big (365MB) but was completely blank... meaning it was pure white.  There must be an error within ArcGIS but where that is occurring right now is unclear.  I'm hoping she'll try and 16-bit and that will resolve it the problem tomorrow.

Oshyan, I'm unclear as to what the company is doing to the file before they give it to me but I know they not just using ArcGIS to export the file.  I've asked for the original data and will see what I can do with it when it comes.  I can't be the first one to do this so I assume there is an easy solution to the problem.

Some of the forums I'm reading are suggesting 32-bit can get too large and the program has a fit and gives up... hence the blank file.

I'll keep this post updated as I go through the process.

[Oshyan]

What did you view the 32 bit file in to determine it was blank? Did you try to load it into Terragen?

*Any* 8 bit format is going to be "blocky". That's a limitation of 8 bit resolution/accuracy (only 256 possible levels of height *in total*!), not an issue with the source data or Terragen. 16 bit or 32 bit are necessary for good quality.

PNG and JPG don't have the capability to store 16 bit values per channel. PNG can handle 16 bits in a single channel with grayscale, which could work for your needs, but it's rarely used and not well supported. So I'm not surprised ArcGIS doesn't handle it. Possibly it can do JPEG2000? But TIFF would really be the ideal if you can get it to work.

- Oshyan