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bio website staff.acecrc.org.au/~mdsumner
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visits member for 3 years, 5 months
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R, Manifold, GDAL, also interested in Python, topojson/D3 and NetCDF/HDF


Apr
22
awarded  Nice Answer
Feb
18
comment gdal_contour creates an empty shapefile
can you give us the output of gdalinfo hazard_interp4.asc -stats ?
Feb
14
awarded  Necromancer
Feb
12
comment How to record tracks finer than 10-30cm resolution (possibly using an iPhone)?
Bread crumbs or cotton?
Feb
6
comment Difference between gdal versions in reading raster on two machines?
try using readGDAL() directly in rgdal package to isolate whether it's a raster package issue or not
Jan
17
comment Spatial indexing of a point pattern in R
answered here, please declare cross-postings if you must do it, it's a fairly basic courtesy stat.ethz.ch/pipermail/r-sig-geo/2013-January/017222.html
Jan
4
comment Converting geographic coordinate system in R
rgdal does recognize EPSG:2056, FWIW
Jan
1
comment Giant 2.5 GB JP2 image: How to tile it?
try gdal2tiles.py
Dec
12
comment Tiling Rasters based on an existing Polygon Shapefile (Vector Grid)
You would have to add the looping part but see the cutline and cwhere arguments to gdalwarp, I think together you could crop out tiles based on each tile in the vector source.
Dec
12
comment How to create cohesive Spatial Pixels from Spatial Points Dataset
I think I see what you mean, to interpolate a new grid from irregular data you need a base grid first that covers the region at a sensible resolution. You can do this pretty easily by hand using the tools, but take a look at trip::makeGridTopology for a stab at generalizing it while keeping all the options open. You still need to generate the Data part but it's not hard. If this sounds right I will answer with an example and wrapper function (that might be more generally useful).
Dec
11
revised How to produce spatial grid from raster?
added 541 characters in body
Dec
11
revised How to produce spatial grid from raster?
added 541 characters in body
Dec
11
answered How to produce spatial grid from raster?
Dec
8
comment Converting a .jpg map into a shapefile
jpg is probably the worst format for digitizing like this though, JPEG compression is lossy and no good for clean straight lines and so on. You cannot reconstruct good data from a JPEG once it's been in that format.
Dec
6
comment How to georeference an areal photograph given known coordinates of the four corners and center of the image
use gdal_translate with argument a_ullr for "assign upper left, lower right.
Dec
5
comment Exporting Grid from R to use it in ArcGIS
FWIW raster, sp, and rgdal all provide independent support to create ESRI Ascii files, but it's a very poor choice given the lack of projection metadata, tiling, or compression and inconsistent support for non-square cells
Dec
5
comment Exporting Grid from R to use it in ArcGIS
You need to specify what the target software can read, or at least what version of it you are using so someone can find out. Recent versions of ArcGIS use GDAL so rgdal is the best place to start. GeoTIFF is generally the best choice unless you have special needs
Dec
4
awarded  Organizer
Dec
4
revised How can we stop Manifold from writing TMP files?
edited tags
Dec
3
answered What are the alternatives to Manifold GIS?