1,834 reputation
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bio website staff.acecrc.org.au/~mdsumner
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visits member for 3 years, 8 months
seen 4 hours ago

R, Manifold, GDAL, also interested in Python, topojson/D3 and NetCDF/HDF


2d
comment Generating polygons with shared boundaries using QGIS?
Surely qgis has a suite of snap-to controls. That would do it wouldn't it?
Jul
19
comment NAs not allowed error message in attempt to plot raster object in R
Please show all the code used. Can you point to an example file.
Jul
15
comment QGIS .tif is not a supported raster data source
I reckon it's not actually a TIFF. The extension is not a reliable indicator of the contents, where did you get it?
Jul
3
comment Conversion problem of projection of MODIS LAI from sinusoidal to geographic
I understand, I just think you have a job to do but this is a distraction. If this is the job, confirm the source crs is right and then use projectRaster to transform to the target crs. What is projection(lai_real) directly after you load it with raster?
Jul
3
comment Conversion problem of projection of MODIS LAI from sinusoidal to geographic
projection()<- assigns a crs, it does not do the transformation. Do you really need to warp this yhing or do you just want to extract from it?
Jul
2
comment Which projected coordinate system should be used for mapping the US?
colorado.edu/geography/gcraft/notes/mapproj/mapproj_f.html andhttp://www.georeference.org/doc/guide_to_selecting_map_projections.htm
Jun
29
comment How to exactly georeference in QGIS
More details please.
Jun
26
comment Processing HDF4 data in R
HDF4 can be built into rgdal by building it into GDAL, it's not straightforward: scigeo.org/articles/…
Jun
25
comment Map project a raster having separate latitude and longitude raster bands
My email is in my profile. Send a link to the original source rather than the file if possible
Jun
25
comment R plot raster with real colors
Use raster or brick on the file name, not via rgdal. If it is a palette raster() and plot will work, if rgb then brick and plotRGB will work.
Jun
25
comment Map project a raster having separate latitude and longitude raster bands
Can you point to a specific file? I am keen to check it out
Jun
25
comment Map project a raster having separate latitude and longitude raster bands
gdal has built-in support for this, though my experience is limited. See here for an example: lists.osgeo.org/pipermail/gdal-dev/2012-February/031756.html I also think gdalwarp infile outfile.tif will do something.
Jun
24
comment Dem file in .adf format, while .tiff is needed
In GDAL it is not the extension that defines the output format. GTiff is the default
Jun
22
comment R plot raster with real colors
We need to what raster source is referenced by thay VRT. It may be rgb or palette but no point in us guessing.
Jun
22
comment R plot raster with real colors
Show some code! Use ?brick and ?plotRGB. We can only guess what your actual problem is
Jun
19
comment How to compute the outline of multiple tracks?
alpha shapes / hull
Jun
17
comment Error in which.max() : not yet implemented for large objects in R
Decompose the problem into manageable sub-tasks and implement those. You want a single layer where each pixel value is the layer number with the max value of that pixel? The raster package has many ways to do that. At most brute you can just loop over seq_len(ncell(r[[1]])) and use extract with base::which.max to get the layer for each pixel.
Jun
12
answered Creating a loop for Lines data (spatial data)
Jun
11
comment How do I convert a VMAP to a shapefile using GDAL?
Can you explain what VMAP is and point to an example? Why do you want a shapefile and can that substantially represent the source? What does ogrinfo report on the source data?
Jun
11
comment 50m x 50m grid around the world
Check out c-squares cmar.csiro.au/csquares/about-csquares.htm but many other options, like the L3 SeaWiFs bins on a sinusoidal equal area projection, or any modernish image tile service. It really comes down to the projection you decide but easy enough to roll your own or adapt.