Ok, here are more details: I am using Python (2.6) together with netCDF4, numpy and gdal/ogr. So far, I am able to read the dimensions, attributes and variables. I have to choose records depending on certain time slices and export these records together with their dimensions into a shapefile. So, if four time slices are selected four shp files will be created. Currently, I am designing a GUI with Tkinter for data I/O and time slice selection. For the conversion task i would prefer a direct method without caching into a file. I may use normal arrays or pytables.... Just wanted to know what is the more efficient method for caching the data. Thanks for your support Mike!
> Date: Wed, 16 Mar 2011 16:21:23 +1100 > Subject: Re: [gdal-dev] netCDF to Shapefile > From: mdsum...@gmail.com > To: manuelrai...@hotmail.com > CC: gdal-dev@lists.osgeo.org > > Hi Manuel, I think you will still need to be more specific. You've > indicated that the data is points, but not what the variables in the > file are, which variables need to be interrogated for coordinates vs. > values, what their dimensions are, whether you want several > shapefiles, or just one with (say) multiple attributes, etc. > > There are a number of ways to convert such data to shapefile, but it > might be best to choose a reasonably easy scripting language to do it, > such as Python or R - and so there are probably better forums than > this for your problem. > > Either way you'll need to provide a lot more detail - it's likely to > be a two step process, with converting the NetCDF grids to tables (in > memory or file), and then those to point shapefiles. > > Cheers, Mike. > > On Wed, Mar 16, 2011 at 3:17 PM, Manuel Rainer <manuelrai...@hotmail.com> > wrote: > > Thanks for your help, > > it has to be a Shapefile because we do some further processing (symbology, > > map creation...). > > The netCDF file contains hydrodynamics point data. > > > > Best regards > > Manuel > > > > ________________________________ > > Date: Wed, 16 Mar 2011 09:32:16 +0530 > > Subject: Re: [gdal-dev] netCDF to Shapefile > > From: chaitanya...@gmail.com > > To: manuelrai...@hotmail.com > > CC: gdal-dev@lists.osgeo.org > > > > Manuel, > > > > Shapefile is for vector formats alone. Try a raster format to convert the > > netCDF data. > > > > As for the performance, you don't need to cache anything. But it may help to > > tweak the GDAL_CACHEMAX setting. > > http://trac.osgeo.org/gdal/wiki/FAQRaster#Howtoimprovegdalwarpperfomance > > > > On Wed, Mar 16, 2011 at 8:21 AM, Manuel Rainer <manuelrai...@hotmail.com> > > wrote: > > > > Hi, > > > > I would like to convert certain time slices (records) out of a netCDF file > > to a Shapefile. > > The netCDF file has 7> GB, so what is the best proceed to get an appropriate > > performance? > > I mean, should the data be cached (e.g. in an ASCII file, ...) > > before writing a Shapefile or can the shp directly be generated? > > Perhaps you have some experiences... > > > > Thanks for your help! > > Best regards > > Manuel > > > > > > > > _______________________________________________ > > gdal-dev mailing list > > gdal-dev@lists.osgeo.org > > http://lists.osgeo.org/mailman/listinfo/gdal-dev > > > > > > > > -- > > Best regards, > > Chaitanya kumar CH. > > /tʃaɪθənjə/ /kʊmɑr/ > > +91-9494447584 > > 17.2416N 80.1426E > > > > _______________________________________________ > > gdal-dev mailing list > > gdal-dev@lists.osgeo.org > > http://lists.osgeo.org/mailman/listinfo/gdal-dev > > > > > > -- > Michael Sumner > Institute for Marine and Antarctic Studies, University of Tasmania > Hobart, Australia > e-mail: mdsum...@gmail.com
_______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev