I have a COG with a scale factor (excerpt from GDALInfo)
Band 1 Block=1024x1024 Type=Int32, ColorInterp=Gray
Min=-50313.000 Max=57304.000
Minimum=-50313.000, Maximum=57304.000, Mean=4745.177, StdDev=7550.452
NoData Value=-32767
Offset: 0, Scale:0.1
How do I apply this scale factor in FME? If I clip the input and create a new tif, the scale factor is dropped and the values are 10 times the expected.
In this particular case I can just scale the value back down, but in general, is there a way to retrieve the scale factor and apply it?
Question
Scale factor on COG
+38- Contributor
+59- Evangelist
Untested, as I don't have a COG at hand, but the documentation mentions
| geotiff_exif_digitalzoomratio | Represents the digital zoom ratio when the image was shot. If the numerator of the recorded value is 0, this indicates that digital zoom was not used. |
Hopefully this attribute is related to the scale GDALInfo mentions.
+26- Safer
Hi
I don't believe FME currently supports scale factors in GeoTIFF.
I have submitted an internal ticket for our development team (internal reference: FMEENGINE-87393) to explore the possibility of implementing this. I will make sure to update you on the progress.
+38- Contributor
Hi
I don't believe FME currently supports scale factors in GeoTIFF.
I have submitted an internal ticket for our development team (internal reference: FMEENGINE-87393) to explore the possibility of implementing this. I will make sure to update you on the progress.
Even an interim solution where the scale factor can be retrieved as metadata would be a useful step forward.
+38- Contributor
+26- Safer
Hi
I'm sorry for the late response!
While our development team continues to look into this, you could try embedding an external tool or Python into Form.
Perhaps a library like this may be able to extract metadata, such as scale factor: https://pypi.org/project/tifftools/