[Qgis-user] Fwd: qgis - v.vol.rst from grass

[Nicolas Cadieux]

Hi, 
Some form of Kriging is probably best.  But it requires a very good understanding of each data set and its distribution on the variogramme.  Make sure you study each variable separately for each layer. If you need to query the data first and save the result to a new file, that will be two steps.  Having only the data you need will reduce the amount of manipulation errors.  Keeping track of data manipulation is easy if you have a good file convention.  Ex data.shp becomes data_query_z<250.shp. 
Good luck,
Nicolas

> Le 28 oct. 2018 à 13:29, Francois Chartier <fra.chartier at gmail.com> a écrit :
> 
> I am trying to interpolate particle size of soils, which i will then transform into a permeability. 
> the option to stack multiple raster is the path i am going to use, and i think kriging is the probably the most suited for soil properties. Inverse distance should be good and lighter in terms of computation. 
> i have to figure out to run the interpolation based on a query result.  i am not sure if this has to be a 2 step process or 1 step. 
> 
>> On Sun, Oct 28, 2018, 11:34 Nicolas Cadieux, <nicolas.cadieux at archeotec.ca> wrote:
>> Hi,
>> 
>> This is interesting.  Basically the end result is a multi band raster, which can also be done by stacking multiple band rasters.  I don’t know anything about this v.vol.rst algorithm but it sound interesting. I do do see a problem though. Your data sets may not all like to be interpolated with a single algorithm. So unless you can modify the interpolation algorithm for each  band, you will probably end up with a bad raster data set.  The chosen algorithm must work like the phenomenon you are trying to study.
>> 
>> As an example, using a simple TIN to predict the weather will most likely fail as weather pattern don’t work like a TIN. Inverse distance weight would probably be better.  
>> 
>> Nicolas
>> 
>> > Le 28 oct. 2018 à 11:00, Francois Chartier <fra.chartier at gmail.com> a écrit :
>> > 
>> > Hi
>> > 
>> > Is the plugin v vol rst available from within qgis?  i didnt see it in the list of vector plugin from grass. 
>> > i am looking for a 3d interpolator and i believe only grass can do this in open source.  
>> > Are there other plugins that can do 3d interpolation?  
>> > by 3d i am not referring to interpolation of elevation, but by interpolation of 3d dataset with xyz + attribute (ex: soil moisture), with data points vertically stacked, and would need to interpolate verically and horizontally.  
>> > 
>> > thks
>> > f
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