You can easily do that using SQL.
Since QGIS 2.14 you can create Virtual Layers based on SQL Queries to load
layers on your canvas. I believe using the following query will work:
select t.origin_gid, t.target_gid, t.target_value, t.geometry
FROM
(Select f.gid as origin_gid, g.gid as target_gid, g.value as target_value,
g.geometry
FROM layer_1 as f, layer_1 as g
WHERE f.gid >= g.gid and st_within(g.geometry, st_buffer(f.geometry,
f.value))
ORDER BY f.gid, g.value ASC) as t
group by t.origin_gid
Alexandre Neto
Niccolò Marchi <sciurusurba...@hotmail.it> escreveu no dia sexta,
12/08/2016 às 12:24:
> Hi all,
>
> I have a set of projected spatial points (id, x, y, dist, value) that
> needs to be filtered. For each point I have to find the other ones falling
> within a variable distance. For each selection, I need only the one with
> the maximum value or, if duplicated, keeping just one.
>
> I tried to check the available tools and I found out what follows:
>
> - A simpler possibility would be to use the “Select by
> expression”, but I’m not that familiar with the syntax and I ended up with
> [clearly non-working]: CASE WHEN distance($currentfeature)<”dist” THEN
> max(“value”) END
>
> - Another possibility would be to improve the following R code,
> available online (thanks to the author)
>
> Any (R, Python, else) suggestion?
>
>
>
>
>
> ##Layer=vector
>
> ##ID=Field Layer
>
> ##distance= Field Layer
>
> ##Output= output vector
>
> library(rgeos)
>
> library(sp)
>
> library(spdep)
>
>
>
> coordi <- as.matrix(coordinates(Layer))
>
> tram_nb <- dnearneigh(coordi, d1 = 0, d2 = distance,row.names=Layer[[ID]])
>
> tram_nb<-as.data.frame(card(tram_nb))
>
> tram<-cbind(as.vector(Layer[[ID]]), tram_nb)
>
> Coord<-cbind()
>
> n<-length(Layer[[ID]])
>
> for(i in 1:n){
>
> if (tram[i,2]!=0 ){ Coord <-rbind(Coord,cbind(coordi[i,1],
> coordi[i,2],as.vector(Layer[[ID]])[i]))
>
> }
>
> }
>
> x<-as.numeric(Coord[,1])
>
> y<-as.numeric(Coord[,2])
>
> X<-cbind(x,y)
>
> matrix<-as.matrix(X)
>
> matrix<-SpatialPointsDataFrame(matrix,as.data.frame(Coord),proj4string=CRS(Layer))
>
> Output=matrix
>
>
>
> Thank you in advance for your help!
>
>
>
> All the best,
>
>
>
> Nic
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user@lists.osgeo.org
> List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
--
Alexandre Neto
---------------------
@AlexNetoGeo
http://sigsemgrilhetas.wordpress.com
http://gisunchained.wordpress.com
_______________________________________________
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user
