Re: [Qgis-user] Generating black white from RGB landsat using Raster Map calculator?

[Micha Silver]

Hello Chas On 01/17/2018 01:52 PM, Chas Sheen wrote: Richard,   I should have made my initial query clearer. I am trying to output a black and white geotiff. It's still not clear what you are asking. AFAIK, there's no such thing as a "black and white geotiff". You can apply any color table you want to any raster. You can apply a gray scale to any of the landsat bands. If you are trying to create a new raster from the three RGB bands using some _expression_, that should work. You can use either of three tools: the built in QGIS raster calculator, or thru the Processing toolbox there's SAGA Raster calculus and the GRASS module r.mapcalculator. Again, none of this has anything to do with coloring. After running the raster calculator, you can color the result with a gray scale color table, a red color table, or any other color ramp you choose. Have split the original (landsat) image into RGB images. When I apply the _expression_ in the capture below, and hit run, nothing is saved to the results directory. I’m assuming that my _expression_ or something else in the raster calculator is wrong? The final product that I’m after is a xyz grid where z is the black-white amplitude…which I think should be relatively easy (?) once I have the black-white image. After you running the calculator _expression_, then you can save the result in many formats, including gridded XYZ, ArcINFO ASCII, or many others, using the gdal_translate tool. This is under the Raster->Conversion menu.   Chas Sheen 0448017282   From: Richard McDonnell [mailto:richard.mcdonn...@opw.ie] Sent: Wednesday, January 17, 2018 7:13 PM To: Chas Sheen <chassheen...@gmail.com>; qgis-user@lists.osgeo.org Subject: Re: [Qgis-user] Generating black white from RGB landsat using Raster Map calculator?   Chas, Two options for splitting RGB into separate images in QGIS. Semi-Automatic Classification Plugin, Preprocessing, Split Raster Bands Grass r-rgb (Processing Toolbox) Any one of these tools will split the Raster for you easy enough Regards, Richard On 17/01/2018 00:48, Chas Sheen wrote: I split the image into R, G, B Worked out in QGIS wher the Raster map calculator is. Run...several times No result foud in Results Directory. It runs quickly then refreshes inputs and logs to blanks. I'm new to QGIS....so have probably left out something basic. Any clues   _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user   -- Richard McDonnell GIS Specialist PgD GIS AssocSCSI OPW FRM Data Management 52 Stephens Green, Dublin 2. TEL: 01 6476543 Email Disclaimer: http://www.opw.ie/en/disclaimer/ _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Micha Silver Ben Gurion Univ. Sde Boker, Remote Sensing Lab cell: +972-523-665918

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