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bio website staff.acecrc.org.au/~mdsumner
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visits member for 4 years, 7 months
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R, Manifold, GDAL, also interested in Python, topojson/D3 and NetCDF/HDF


Jun
12
comment Why does @data@values slot for RasterLayer only contain logical(0) and not the actual values?
Don't use @ unless you are developing internal code - use readAll(NDVI). It happens as a memory-efficiency technique, you can open very large grids as kind of a promise - raster promises to pull in the data (via rgdal, via GDAL in this case) when you actually need the numbers. If you need to save the object as a standalone R object not tied to a file readAll is the way to do it. See ?raster "In many cases . . . does (initially) not contain any cell (pixel) values in (RAM)"
Jun
12
answered Aggregate SpatialPoint to form SpatialPolygon
May
30
comment How to modify or create a wider UTM zone?
Don't do it! Mercator is suited to narrow areas that are parallel to a particular great circle. Use a projection that suits your area. The internet is retarded on this topic.
May
26
answered R apply function in turn to each subset of a spatialPolygonsDataFrame
May
25
comment GDAL doesnot support HDF4 e
Can you check that GDAL has the driver, then maybe it's Python not picking it up properly? Using the gdal-bin that you installed use: gdalinfo --formats | grep HDF4 Other than that it might be a python special thing, dunno
May
25
answered How to make a movie from a ascii grid files?
May
24
revised GDAL doesnot support HDF4 e
added 184 characters in body
May
24
comment GDAL doesnot support HDF4 e
Well, GDAL 1.11.2, released 2015/02/10 but that's kind of not the right question - GDAL is geared to use what you have in your system. If I have libhdf4-dev installed and then I install GDAL, my GDAL comes with HDF4 support. This is on Linux, but it's kind of similar on Windows if you use OSGeo4W.
May
23
answered GDAL doesnot support HDF4 e
May
1
comment Extracting point information from raster in R
I would rather delete this answer than be associated with this idiocy
May
1
comment Extracting point information from raster in R
Idiot, seriously. Ffs
Apr
30
comment Extracting point information from raster in R
That is kind of irrelevant, the effect is the same. cbind gives a matrix
Apr
30
revised Extracting point information from raster in R
clarity (hopefully)
Apr
30
comment How can I loop through a list to create rasters and write them to .tif files?
And btw, surely matlab can write a decent raster file like GeoTIFF or similar rather than just a dump of its workspace. That might be a better pathway, why is R involved at all?
Apr
30
comment How can I loop through a list to create rasters and write them to .tif files?
what is the structure of objects you read in? It's unlikely that raster() understands them, unless they strictly follow the list(x, y, z) structure understood by ?image. I.e. what is str(FSLE2006mat$F2006812)
Apr
30
comment Extracting point information from raster in R
No, that won't affect the results at all in this case, since the y query has no metadata about the projection.
Apr
30
answered Extracting point information from raster in R
Apr
20
comment tfw world file in decimal degrees?
they can be given in degrees, but it would not make sense to apply those to a UTM image - since the world file affine transform assumes "regular spacing" in x/y (possibly with affine shear) - it's the fault of the data producer to not include basic metadata, you can probably figure it out if they are not forthcoming (is there any other auxiliary files with the data? what are all the files you have?)
Apr
11
comment create tracks file from points
I think it's perfectly clear what the OP wants. Is use of R an option, it's pretty straightforward to do this. AI is not really suited for this kind of work
Apr
10
comment R: How to get latitudes and longitudes from a RasterLayer?
Thanks, I added the as.data.frame step. I think it's terrible advice to add the coordinates as attributes - especially by munging with slot - since the coordinates of the object can change. If you want a raw data.frame just make one. I don't care where the information is, maybe just edit yours and we can zap this answer.