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bio website staff.acecrc.org.au/~mdsumner
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visits member for 3 years, 10 months
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R, Manifold, GDAL, also interested in Python, topojson/D3 and NetCDF/HDF


Apr
8
answered What programs would allow for the mapping of a geoid in 3d?
Apr
2
answered R - color SpatialLines by attribute
Mar
26
comment How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS
In R, start with library(raster);(ncdata <- brick("file.nc")) and report back on what you get. You'll need either ncdf4 or ncdf packages also installed for raster to use.
Mar
25
revised What programs would allow for the mapping of a geoid in 3d?
fixed radius
Mar
25
revised What programs would allow for the mapping of a geoid in 3d?
updated to use delaunayn from geometry package
Mar
24
answered What programs would allow for the mapping of a geoid in 3d?
Mar
24
comment What programs would allow for the mapping of a geoid in 3d?
R's rgl could do this, can you add a link to the data and I will have a go.
Mar
23
comment Is it possible to render tile-based web mapping projects in any other projection than web mercator?
Yes of course it's possible, just use gdal2tiles it's really easy. Interoperability, not sure, but I don't see that it's really relevant. Mercator is a terrible projection, it's just a simple compromise for the entire globe in one plane. There's also longlat, Cylindrical Equal Area, Peters, and none are "very good" because they apply to the whole world, but they work in a narrow context for a purpose.
Mar
10
comment Problem with MIF/MID allignment
"Some other software" is not descriptive enough for this site. You should describe exactly what you are using and the steps used.
Mar
10
comment I want to reproject data from 0-360 to -180 - 180
You can create a VRT data set to do the job: trac.osgeo.org/gdal/wiki/UserDocs/RasterProcTutorial
Mar
8
comment Raster: mosaic first, or project first?
I don't the second option makes any sense, there will be edges broken everywhere. Option 3 is just a way of achieving 1. Do a test with 3 and then commit that VRT to a tiled and compressed GeoTIFF if the performance is too slow.
Mar
8
comment Per-pixel (statistical) calculations on a raster stack using GDAL
It might be worth looking closer to find a faster way in R/raster, there are a few ways to do it and the details matter. Happy to do that perhaps outside this q if you want
Mar
6
comment How can I correct a .pgw file for a PNG image?
There's obviously no coordinate system metadata so I would check that the right one is assigned or in-use when you load it. It is probably being displayed with an assumed projection that is wrong. (Best to use a spatial format like GeoTIFF that can store all this stuff but hardly anyone does unfortunately)
Mar
6
comment gdal2tiles generates small picture inside 256x256 tile
This works if I do this, with no -z argument: python gdal2tiles.py -p raster ibcso_background_hq. tif ibcsoraster I can maybe have a closer look later, but it might be something to do with how the levels interact, but otherwise def a bug in the script.
Mar
3
comment gdal2tiles generates small picture inside 256x256 tile
Can you make a simple example, or at least give more details on the kind/s of source image and the actual commands used? Are you transforming somehow from the source because afaik that is not going to work in a single step
Mar
3
comment What is the easternmost point in the US?
What about the Amundsen-Scott base on the South Pole?
Feb
25
comment What format to store/use four band Raster data
I still think GeoTIFF is the best, it is hard in software design to cover all possibilities in read/view software and provide a sensible default, but anything worth using will allow you to change a default interpretation. Perhaps this q should be about the specifics of that for your targets?
Feb
25
comment How to convert a .tif with .tfw to a GeoTiff?
You also need to ensure that a coordinate system is set with -a_srs otherwise it is kind of a malformed GeoTIFF.
Feb
17
comment What is the latest version of R that supported gpclib?
3.0.2 plus 10 chars for so
Feb
15
comment Dates are off when opening netcdf file in R
ISOdatetime(1950,1,1,0,0 ,0,tz="GMT")+508008 * 3600 # [1] "2007-12-15 GMT"