I have a raster data set where the flag value is 255, representing either no data or a background value.
If I use EXTRACT to try and get the average values for a region, it treats 255 as a valid data value. The flag definition appears to have no effect.
Is there any way around this?
Dear Stephen,
Areas that are known to be background pixels are typically not included in the feature image. The flag value that you set does not influence the extract module. Only a handful of modules in IDRISI make use of the flag value and these are specified in the help section. To remove these values from the analysis I suggest altering the feature image to exclude the flagged pixels. Alternatively you could use the QUERY module, but a feature definition image would still need to be built.
Best Regards,
Andrew Hostetler
Clark labs Technical Support Team
