[Qgis-user] raster with distance values from a point

[Nicolas Cadieux]

Interesting Kirk,

The QGIS vector to raster conversion is not available in the graphical modeler or do you have another reason behind your solution? I don’t use much the graphical modeler so I appreciate your incite.

Cheers!

Nicolas Cadieux
https://gitlab.com/njacadieux

> Le 25 févr. 2021 à 15:44, Kirk Schmidt <kirk at nortekresources.com> a écrit :
> 
> 
> To add to Nicolas" comment:
> 
> 1) Create your point layer from a csv (easting, northing id) as a minimum
> 
> 2) If you want to stay with process modeler, use the SAGA>Raster creation tools> Rasterize Algorithm to convert the point layer to your required resolution and size
> 
> 3) Use the  GDAL>Raster Analysis>Proximity or SAGA>Raster tools> Proximity Raster  to create your output.
> 
> Kirk Schmidt
> 
> On 2/25/2021 4:24 PM, Nicolas Cadieux wrote:
>> Hi,
>> 
>> You can cut down you use of several plugins by doing the following,
>> 
>> 1) Create a vector point file with a single point having the numerical field containing the value 1.  This file could be a csv containing WKT.
>> 
>> 2) Use the vector to raster conversion.  (This will take your vector point file, an create a raster of x,y dimensions.  You point will become 1 and all other values will be 0.
>> 
>> 3) Use the Proximity raster distance gdal function.
>> 
>> This requires no plugins so it should be easy to create a graphical modeler.  My favorite way would be to go to strait Python and to call the gdal proximity function from my Python script.  If you had hundred or thousands of these to do, I could develop a Python script that could automate the entire thing.   Contact me if you have questions.
>> 
>> Nicolas Cadieux
>> 
>> 
>> 
>> On 2021-02-25 12:58 p.m., Fabio Falchi wrote:
>>> 
>>> Dear all,
>>> 
>>> not having received any answer, I repeat the request.
>>> I need to speed up the process of obtaining rasters with distances from a single point (or a single lat-lon coordinate) in it. Manually I use this procedure:
>>> With a georeferenced raster in a UTM projection I use raster calculator to obtain a raster with all pixels set to zero. Then, with Serval plug-in, I manually set to 1 the value of the pixel in the wanted position (either by using a satellite overlay or by using a point vector layer with the appropriate coordinates). Then I use the proximity function under Raster>Analisys menu.
>>> I want to make this via the Graphical Modeler, in order to be able to make the process fast and skip the manual introduction with Serval plug-in. At the very least, I need a mode to put the value 1 in the pixel of the selected null raster in the position givel by lat-lon coordinates. 
>>> Thank you!
>>> Best,
>>> Fabio Falchi
>>> 
>>> USC - Universidade de Santiago de Compostela
>>> 
>>> ISTIL - Light Pollution Science and Technology Institute
>>> 
>>> 
>>> Il sabato 20 febbraio 2021, 18:04:14 CET, Fabio Falchi <fabio_falchi at yahoo.it> ha scritto:
>>> 
>>> 
>>> Dear all,
>>> 
>>> I need to speed up the process of obtaining rasters with distances from a single point in it. Manually I use this procedure:
>>> With a georeferenced raster in a UTM projection I use raster calculator to obtain a raster with all pixels set to zero. Then, with Serval plug-in, I manually set to 1 the value of the pixel in the wanted position (either by using a satellite overlay or by using a point vector layer with the appropriate coordinates). Then I use the proximity function under Raster>Analisys menu.
>>> I want to make this via the Graphical Modeler, in order to be able to make the process fast and skip the manual introduction with Serval plug-in. At the very least, I need a mode to put the value 1 in the pixel of the selected null raster in the position givel by lat-lon coordinates. 
>>> Thank you!
>>> Best,
>>> Fabio Falchi
>>> 
>>> USC - Universidade de Santiago de Compostela
>>> 
>>> ISTIL - Light Pollution Science and Technology Institute
>>> 
>>> 
>>> 
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>> -- 
>> Nicolas Cadieux
>> https://gitlab.com/njacadieux
>> 
>> 
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> -- 
> Kirk Schmidt, MScF, BScF, RPF
> General Manager
> Nortek Resource Solutions Inc.
> RR # 1
> Thorburn, NS
> B0K 1W0
> Tel (902) 922.3607
> Email: kirk at nortekresources.com
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