topic Re: Chanigng NoData Values in GeoTIFF files in Data Management Questions

Chanigng NoData Values in GeoTIFF files

RachelAlbritton — Sat, 14 Sep 2013 18:30:21 GMT

I'm using LIDAR data that are in a floating point GEOTIFF format. These files contain "void" areas. The GEOTIFF format does not have a standard tag for a nodata value. To indicate areas where there is no data, those cells have been filled in with an IEEE Not a Number value (per the source of the data). I need to be able to change these "void" values with 0 (or some other value).

When I click on the cells with "void" areas the window shows the pixel as NoData, however, if I run the IsNull tool on the file the results indicate that there are not any cells that contain NoData (please see attached). So how can I change the value of these "void" areas when I can't find a way to identify them?

Re: Chanigng NoData Values in GeoTIFF files

RachelAlbritton — Sat, 14 Sep 2013 21:07:08 GMT

I figured out a way to identify the value of the NoData Cells, but I'm still not sure if this was the best method:

I converted the floating point raster to integer based DEM. Next I used to the reclassify tool to look at all the unique elevation values. There were two very large negative values that I reclassified to 0 and left all other values the same. This seemed to work, although the elevation values are now not as accurate as before.

If anyone else knows of a better way to address this issue I'd be interested to know.

Re: Chanigng NoData Values in GeoTIFF files

AlfredWagtendonk — Thu, 09 Jun 2016 11:44:30 GMT

I had a similar problem and first tried to convert my data as well. But, than noticed my Geotiff had a compression applied ('PACKBITS'). After exporting my dataset (right click layer =>Export Data) to an uncompressed Tiff (Compression type: NONE), the problem was solved: NoData cells behave again like expected. So have a look at your layer properties to see if your Tiff has been compressed as well and if so uncompress it.

Good luck and best wishes,

Alfred Wagtendonk