[GRASS-dev] histogram equalization not working with Landsat 8 data?

GRASS GIS GRASS GIS developer
1

I just uploaded some Landsat 8 data into GRASS 7.0.2. It shows up OK at grey scale but disappears if I try to do a histogram equalization stretch. I wonder if this is because it is 16bit now? Has anyone else run into this?

Michael

C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Head, Graduate Faculty in Complex Adaptive Systems Science
Arizona State University

voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

2

Solved. I needed to set the region to match the map. Didn’t know that is required to set a color table.

Michael

C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Head, Graduate Faculty in Complex Adaptive Systems Science
Arizona State University

voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Nov 25, 2015, at 5:02 PM, Michael Barton <michael.barton@ASU.Edu> wrote:

I just uploaded some Landsat 8 data into GRASS 7.0.2. It shows up OK at grey scale but disappears if I try to do a histogram equalization stretch. I wonder if this is because it is 16bit now? Has anyone else run into this?

Michael

C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Head, Graduate Faculty in Complex Adaptive Systems Science
Arizona State University

voice: 480-965-6262 (SHESC), 480-965-8130/727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

3

On 26/11/15 01:09, Michael Barton wrote:

Solved. I needed to set the region to match the map. Didn’t know that is
required to set a color table.

It is not needed for setting the color table per se, but the histogram is calculated within the current region setting, so for histogram equalization it is necessary.

Moritz