[Qgis-user] Problem with Rasterize (Vector to raster) tool

[Carlos Cerdán]

Perhaps raster calculator can also help you

Expression:

 (layer>0 and layer <= 1)

Gives us 1 when sentence is true and 0 for false, for each cell in "layer".

Good luck

Carlos




2014-04-10 9:29 GMT-05:00 Micha Silver <micha at arava.co.il>:

>  Using GRASS there are two modules you can consider. First :
> v.to.rast in=... out=... type=point use=val value=1
> will convert points into raster cells (at the current region settings),
> where any cell that contains at least one point will be given value 1.
>
> Next:
> r.in.xyz in=... out=... method=sum
> will create a raster (at the current region settings) where each cell will
> have a value = the count of points in that cell.
>
> HTH,
> Micha
>
> On 04/10/2014 04:20 PM, Colin D. MacLeod wrote:
>
>  Hi All,
>
> I'm a fairly experienced GIS user, but I'm new to QGIS. I'm using version
> 2.2, and I'm trying to convert a point data layer into a raster data layer
> using the Rasterize tool. The point data layer has an integer field with a
> value of 1 for all records, and I want to make a raster data layer which
> has a value of one for each cell which has at least one point in it (some
> cells have more than one point in them). When I use the Rasterize tool, it
> creates the raster data layer fine, but all cells with have points in them
> appear to have a value of 0.995968. I've tried editing the gdal code (even
> making the resulting raster data layer an integer layer), but I still
> cannot get it to produce a raster with a value of 1 rather than just a
> number very close to one.
>
> Does anyone have any suggestions of where I might be going wrong and/or
> how to solve this issue?
>
> On a related note, is it possible to use the Rasterize tool to work out
> the average or total values for all the points which fall in each grid
> cell? If so, how (I can't find anything in the gdal instructions themselves
> which would suggest this is possible, but I might be missing something). If
> this isn't possible to do with the Rasterize tool, are there other tools in
> QGIS which can do this?
>
> Thanks for any help anyone can give on this.
>
> All the best,
>
> Colin
>
>
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