1,954 reputation
816
bio website staff.acecrc.org.au/~mdsumner
location
age
visits member for 4 years, 1 month
seen 8 hours ago

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


Sep
15
comment Avoiding R for windows gui front-end has stopped working error?
Try with rgdal instead, but if you don't have the system resources it's not going to work. I.e. forest <- readOGR("F:\\NDVI_MODIS_500\\Mod_ndvi_500_shapes", "mod_ndvi_500_grid_point_03_forest_steppe"); 32-bit R is a real limitation. How many points is it? Can you read a subset first? Also, try with QGIS to do this.
Sep
10
comment Guessing a map projection by its values
Curlew: how is UTM easy to identify? There are 60 (bare minimum) different ones, let alone different hemispheres and different national grids at different times in history. It might be data for a different planet or some other purpose entirely. No answer is possible without some knowledge of the data itself: this has to be heuristic and sociological, the very best way is that the person/s responsible provide the actual required information. (It's mad that it's so often neglected).
Sep
10
comment Is there a limitation on the numbers of layers that can be displayed in QGIS?
Consider Manifold over Mapinfo btw.
Sep
10
comment Is there a limitation on the numbers of layers that can be displayed in QGIS?
Fyi sounds like a "max no. open files limit": hub.qgis.org/issues/4013
Sep
9
comment Polygon Between Contour Line
You could just use Manifold to do this ("areas" is a basic contour option) if you're not wedded to ArcGIS.
Sep
3
comment GDAL for Python: extracting subdomains from NetCDF file?
It is actually really straightforward with GDAL. Start by getting the gdalinfo output of your file, and the variable within that you want. Probably it will present as a subdataset in the file.
Sep
3
comment GDAL for Python: extracting subdomains from NetCDF file?
Why reproject? Especially, why reproject to utm? What have you tried already with GDAL? This reads like "here is my task, please do for me"
Sep
3
comment Reprojecting MODIS Ice Sea Temperature products with gdalwarp
"latitude_of_center" looks wrong, and look at the bbox in longlat from GDAL - you'll need to sort out what it's meant to be
Aug
30
comment Kernel Density Analysis using R and ArcGis
Try library(raster); raster(denRedwood) and see ?writeRaster for tiff etc. You'll need to restore the crs which spatstat does not have. See ?projection
Aug
23
comment How to correctly resize raster GIS images to a given px width?
add -co TILED=YES and -co COMPRESS=LZW for more efficient access and storage, if your target usage can utilize those options
Aug
23
answered How to produce “SpatialPixelsDataFrame” from stacked RasterLayer?
Aug
18
comment Using very large image formats with GDAL
and -co COMPRESS=LZW
Aug
14
comment How to extract DEM (Digital Elevation Model) from 3D model
Can sketchup write any of these with z as attribute or coordinate? gdal.org/ogr_formats.html. If so then this should help: gdal.org/gdal_rasterize.html
Aug
13
comment Viewing/understanding NetCDF files
Usually by start and count for each dim. You save storing unnecessary values, i.e. redundant coordinates for every element. Still, relational dbs are ultimately more efficient but CSV is pretty low grade in that arena.
Aug
13
comment Viewing/understanding NetCDF files
It really depends on which files and sometimes which tools you need to usr, it is a very general format. R's raster package and GDAL have high level models of a wide variety of files, most other interfaces are very low level: gis.stackexchange.com/questions/109191/…
Aug
11
awarded  Caucus
Aug
8
comment Whats an appropriate map projection for georeferencing aerial photos?
Matej: you don't need to use the source's projection to georeference with it, you can transform between coordinates. It really shouldn't matter on such a local scale, a local Orthographic would be fine - I'd say it depends more on what you want to use it for and the features/limitations imposed by that.
Aug
7
comment (How) can I write string data to a raster with Python/GDAL?
Start here:trac.osgeo.org/gdal/wiki/rfc40_enhanced_rat_support
Aug
7
comment Looking for Melbourne shapefile?
data.vic.gov.au
Aug
4
comment Are there examples of high-level interfaces to NetCDF
That is right, I didn't mean to imply that. I want analogues to raster or GDAL. But, actually it would use GDAL if neither ncdf or ncdf4 were available and NetCDF were built in to GDAL. But not relevant really