Ask A Cartographer

Output of raster calculator produces only whole number pixels

November 10 2011 | 0 comments
Categories: Map Data

I am conducting a normalized burn ratio using the raster calculator tool. The formula is (band 4 - band 7)/(band 4 + band 7) and expected output is a range of numbers between -1 and +1. TIFF images of bands 4 and 7 were obtained from USGS. These are 8-bit unsigned images with pixels ranging in value from 0 to 255.

The resulting output raster is only composed of pixels with whole integer values of -1 and 0. But when I query pixels on the two tiff images (bands 4 and 7) a wide range of values are found.

What should I do in order to obtain the proper range of pixel values?

Mapping Center Answer:

Try changing your data type to floating point -- you can use the Float tool to do that.

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |