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

[Kirk Schmidt]

Hi Nicholas:

If you activate the various providers under the Processing toolbox 
options, you can have direct access to the various algorithms I 
mentioned.  I often generate a quick general model, export as a python 
script and then refine the script as required.

I am running 3.16.2-Hannover.

Kirk

On 2/25/2021 9:26 PM, Nicolas Cadieux wrote:

> 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 <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
>> Web:www.nortekresources.com
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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
Web: www.nortekresources.com

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