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visits member for 1 year, 2 months
seen Apr 16 at 14:55

Apr
16
asked Arcgis Model Builder - OD cost matrix on network with iteration on attributes
Feb
4
accepted How can I get clean road attributes from OSM data?
Feb
4
answered How can I get clean road attributes from OSM data?
Feb
3
comment How can I get clean road attributes from OSM data?
Thanks Magno C, I wasn't aware of these pages. It will be very helpful. Regarding Robert's remark, I took 'teriary' as an example I found in a previous version of osm data. Having the data under my eyes, I see things such as 'p', 'pah', 'kadjeke', etc. However, it concerns a small minority of records (at the African scale). Thanks for the clarifications about how the data are processed by WeoGeo, this is very interesting.
Jan
31
awarded  Teacher
Jan
31
answered Where can I find a list of states, districts and tehsil names in India?
Jan
31
asked How can I get clean road attributes from OSM data?
Nov
12
comment If road lengths are raster layer, how to calculate road lengths for different buffers?
I'm not quite sure I understand your question. Do you want to know the length of the road network within each cell of your raster layer?
Nov
12
comment Data about administrative subdivisions capital cities
Thank you for your answer. I checked it out, unfortunately there seems to be only polygon features. I couldn't find any data containing cities.
Nov
7
revised Data about administrative subdivisions capital cities
deleted 4 characters in body
Nov
7
asked Data about administrative subdivisions capital cities
Oct
17
comment Impossible to sum rasters because of nodata pixels
Summing was only one part of my problem since I want to get the mean value. I just checked, and the Cell statitics tool is also the easiest way to sum rasters disregarding nodata pixels.
Oct
17
answered Finding a certain length of a line from a central point
Oct
17
accepted Impossible to sum rasters because of nodata pixels
Oct
17
comment Impossible to sum rasters because of nodata pixels
Alright, I just tested the cell statistics tool with the 'ignore nodata' checked and it does exactly what I wanted. I am aware of the shortcomings of such method. However, my work is at a rather large scale, both in space and time, so I assume that such biases will be less important. Anyway, I don't really have so much choice of data.
Oct
17
comment Impossible to sum rasters because of nodata pixels
Thanks for this comment. I asked the managers of the data and they said they calculated the mean value by summing all available data, then divide by the number of days within the month when observations are available on that pixel.
Oct
16
comment Impossible to sum rasters because of nodata pixels
I had a look at the 'spatial analyst/Reclass/Reclassify' tool and it does exactly what I want. I managed to use the batch window in order to process multiple files at once. I have a last problem: if I right-click/fill the 'output raster', it copies the same output files for all input rasters. How can I do to make it create a different output for each input? (i.imgur.com/jzTI2x9.png)
Oct
16
comment Impossible to sum rasters because of nodata pixels
Thanks for your answer. However, I can convert all NULLs to 0 for a single file using 'spatial analyst/Map algebra/Raster calculator'. If I right clic on this tool, I can batch a directory, but what will be the syntax in order to take into account each file automatically? (i.imgur.com/aYaUCzz.png)
Oct
16
comment Impossible to sum rasters because of nodata pixels
Hi, I tried many ways of using the 'reclassify grid values' tool with no success. I started on a raster where I converted all NULL pixels to -9999. I tried to reclassify using the method [0] single, and set 'old value = -9999', 'new value = 0.0', 'operator: [0]=', but all I get is a raster full of 'nan' pixels. What am I doing wrong?
Oct
16
comment Impossible to sum rasters because of nodata pixels
I placed my working directory in a separate folder with only my test.tiff raster in it. I precise that I have full admin privileges. This is what I obtain: i.imgur.com/a3UJC0Y.png Although any other command than gdal_calc.py seems to work perfectly, should I try to reinstall QGIS?