100 reputation
7
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location London, United Kingdom
age 27
visits member for 2 years, 1 month
seen Sep 23 at 7:25

Jun
3
comment R equivalent of GRASS r.grow?
Have you solved this? I have a feeling that you could use focal{raster} to do this... I'll give it some more thought.
Apr
5
comment Handling MODIS NoData cells with gdalwarp
Thanks for this - the problem you describe is exactly what has been concerning me. As I mention above, I've come up with a reasonable work-around for the particular data I'm using, but using dstalpha is something I wasn't aware of and will certainly look at further.
Apr
5
accepted Handling MODIS NoData cells with gdalwarp
Apr
5
comment Handling MODIS NoData cells with gdalwarp
Thanks for this. I've gone ahead and used gdalwarp as I needed to reproject at the same time, but specified srcnodata and dstnodata in the command. What was confusing me was the very specific case where the MODIS product doesn't have a fill value (e.g. MOD09A2 QC layers), however, I've worked around this in Grass.
Apr
3
awarded  Commentator
Apr
3
comment Handling MODIS NoData cells with gdalwarp
Yes, gdal_translate would work too, but what I'm really interested in is how to ensure I don't lose information when setting the NoData value...
Apr
3
comment Handling MODIS NoData cells with gdalwarp
Yes - I couldn't see a satisfactory explanation
Apr
3
asked Handling MODIS NoData cells with gdalwarp
Mar
15
awarded  Teacher
Mar
15
comment r.neighbors produces no output
Answer written up. There's no obvious way to know this, but with Grass its essential to pay close attention to the region settings. Before running commands, type g.region -p in the command line to make sure the settings are as you expect.
Mar
15
answered r.neighbors produces no output
Mar
15
comment r.neighbors produces no output
Have you set the region to match your input raster? i.e. g.region rast=bf03pits
Feb
26
comment How to perform unsupervised classification of LANDSAT time series using Grass?
Good advice @Nikos - I'm going to write a script using the R package 'landsat' to carry out PIF identification for relative normalisation of the tiles. I'll update this post when I have a result.
Nov
22
comment How to perform unsupervised classification of LANDSAT time series using Grass?
Thanks @whuber. This sounds like a good idea, however, the area I'm looking at consists of 11 LANDSAT tiles mosaicked together. Disolacing these and mosaicking them together will produce a massive file and take a long time. Instead, could I make an image group of all the points in the time series and generate a signature for this?
Nov
22
awarded  Custodian
Nov
22
awarded  Editor
Nov
22
reviewed Edit How to perform unsupervised classification of LANDSAT time series using Grass?
Nov
22
revised How to perform unsupervised classification of LANDSAT time series using Grass?
Improved formatting
Nov
21
asked How to perform unsupervised classification of LANDSAT time series using Grass?
Nov
18
comment i.maxlik cannot read i.class output signature file
Yes - checked and double checked. If the file name is entered wrongly the error is 'Unable to open signature file <wrong filename>, so there seems to be something wrong with the file itself.