Re: [Qgis-developer] Processing with raster files > 4GB

Hi all. Il 22/11/2014 14:28, Giovanni Manghi ha scritto: > yes I understand, but we have a clear issue. The qgis raster calc is > broken and when it works it need a very cumbersome logic (especially > for common tasks like reclassifying). GRASS r.reclass works fine, but > it does not allow to ente

Re: [Qgis-developer] Processing with raster files > 4GB

> AFAIK Processing does not import the raster, but uses it as an external data > source > (if not, it should). yes you are right, it uses r.external. >> I agree anyway that it too bad that the qgis raster calculator (and >> georeferencer) are drawing so little attention. Maybe there isn't much

Re: [Qgis-developer] Processing with raster files > 4GB

Il 21/11/2014 15:13, Giovanni Manghi ha scritto: > grass of course does the job, especially when you use the grass data > model from the cli, native grass gui or qgis plugin. Inside processing > large raster suffer from the overhead that is needed to import/export > the raster to, and out of, a te

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Andreas, > It may also be an issue with SAGA or GRASS directly. I have also tested a very large raster (8gb) and SAGA seems to choke also when used natively from the cli interface. grass of course does the job, especially when you use the grass data model from the cli, native grass gui or qgi

Re: [Qgis-developer] Processing with raster files > 4GB

Hi, I was able to do my color replacements with gdal_calc.py. It works fast and efficient. Here is my syntax: gdal_calc.py -A image.tif --outfile=image_output.tif --calc="(A==249)*255+(A!=249)*A" Syntax looks similar to the QGIS raster calculator - but as opposed to the QGIS raster calcul

Re: [Qgis-developer] Processing with raster files > 4GB

Il 19/11/2014 11:41, Andreas Neumann ha scritto: > I will have to do further testing about GRASS. On Windows (OSGeo4W install) > it does > not work too well. It probably works better on Linux. Why so? It shouldn't, at lest not grass64. IMHO dealing with very large rasters is one of the strengths

Re: [Qgis-developer] Processing with raster files > 4GB

Nice to know that gdal_calc works fine ;) I work a lot with gdal + numpy, even for custom tools, and I admit they work very well together! 2014-11-19 11:41 GMT+01:00 Andreas Neumann : > Hi, > > I will have to do further testing about GRASS. On Windows (OSGeo4W > install) it does not work too we

Re: [Qgis-developer] Processing with raster files > 4GB

Hi, I will have to do further testing about GRASS. On Windows (OSGeo4W install) it does not work too well. It probably works better on Linux. The gdal_calc.py solution works very fast though - glad that we came to this solution! Andreas On 19.11.2014 11:25, G. Allegri wrote: And do you ha

Re: [Qgis-developer] Processing with raster files > 4GB

And do you have problems with GRASS (directly, not through Processing)? In GRASS7 you can even drectly write to Geotiff without passing through the internal format (http://grass.osgeo.org/grass70/manuals/r.external.out.html ). If GDAL is built with bigtiff support there souldn't be problems... gio

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Andreas, Yes, you can use gdal_calc.py Certainly you need to perform several processes, but are very fast! Be careful with bands! Perhaps you will want to separate them. Ciao, * * *Carlos López Quintanilla* www.psig.es carlos.lo...@psig.es +34 699.680.261 2014-11-1

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Giovanni, I need to change all pixels that have the value of 249 to a value of 255. All other pixels should stay at their value. Andreas Am 2014-11-19 10:21, schrieb G. Allegri: From my grayscale tiff images I want to replace one pixel value (249) with white (255). All other pixels shoul

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Andreas, you can surely try to import the raster directly into GRASS in a 64bit linux, very often this overcome memory issues, and use mapcalc sintiax, something like: reclassed_raster = if(original_raster == 249,255,original_raster) regards, Roy. GDAL would be my first choice - becaus

Re: [Qgis-developer] Processing with raster files > 4GB

> From my grayscale tiff images I want to replace one pixel value (249) with white (255). All other pixels should stay at the value they have. > > I came across https://github.com/chiatt/gdal_reclassify - but this reclassifies all pixels, not only selected ones. > > Maybe I could use http://www.gda

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Carlos, GDAL would be my first choice - because it easy to automate. However, I don't know how can do my task with GDAL. From my grayscale tiff images I want to replace one pixel value (249) with white (255). All other pixels should stay at the value they have. I came across https://gith

Re: [Qgis-developer] Processing with raster files > 4GB

Hi Andreas, I also had problems to reclassify BIGTIFF with SAGA and GRASS! Finally I used GDAL! Best regards, * * *Carlos López Quintanilla* www.psig.es carlos.lo...@psig.es +34 699.680.261 2014-11-19 9:05 GMT+01:00 Andreas Neumann : > Hi, > > I tried various tools, e.g

Re: [Qgis-developer] Processing with raster files > 4GB

Hi, I tried various tools, e.g. * SAGA reclassify * GRASS r.mapcalc Both work fine on smaller data sets, but fail on big data sets. This is on Win7 64bit, with the OSGeo4W installer. I have 8gb RAM and 40GB disk free on C:, more free space on other disks where the data resides. I am not to

Re: [Qgis-developer] Processing with raster files > 4GB

> Hi, > > I am having a lot of troubles with large raster files and processing. > > The intermediate results can go >4GB. Processing stops with not so > helpful error messages. > > I wonder if processing is hitting the 4GB limit. Can I force processing > to use the BIGTIFF option or a raster format

[Qgis-developer] Processing with raster files > 4GB

Hi, I am having a lot of troubles with large raster files and processing. The intermediate results can go >4GB. Processing stops with not so helpful error messages. I wonder if processing is hitting the 4GB limit. Can I force processing to use the BIGTIFF option or a raster format that can h