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

[Richard McDonnell]

Chas,
The only thing I can see wrong with your equation is the lack of Brackets
Try:

(R*0.2989)+(G*0.587)+(B*0.144)

See Does that help. you should also try the QGIS Raster Calculator, see 
if its an issue with the GRASS Plugin/Instillation.
Regards,

Richard

On 17/01/2018 11:52, Chas Sheen wrote:
>
> Richard,
>
> I should have made my initial query clearer.
>
> I am trying to output a black and white geotiff.
>
> 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.
>
> Chas Sheen
>
> 0448017282
>
> *From:*Richard McDonnell [mailto:richard.mcdonnell at opw.ie]
> *Sent:* Wednesday, January 17, 2018 7:13 PM
> *To:* Chas Sheen <chassheengeo at gmail.com>; qgis-user at 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.
>
>  1. Semi-Automatic Classification Plugin, Preprocessing, Split Raster
>     Bands
>  2. 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
>
>     Displaying image.png
>
>
>
>
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> -- 
> *_Richard McDonnell_*
> *GIS Specialist PgD GIS AssocSCSI*
> *OPW FRM Data Management*
> *52 Stephens Green, Dublin 2.*
> TEL: 01 6476543
>
> <http://www.opw.ie/>
>
>
>
> Email Disclaimer: http://www.opw.ie/en/disclaimer/
>

-- 
*_Richard McDonnell_*
*GIS Specialist PgD GIS AssocSCSI*
*OPW FRM Data Management*
*52 Stephens Green, Dublin 2.*
TEL: 01 6476543
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