[gdal-dev] netCDF to Shapefile

[Manuel Rainer]

thank you guys, a lot of useful information!
finally, I'm tryin' what works best in my case.
 
cheers
manuel
 


Date: Wed, 16 Mar 2011 12:05:18 +0100
Subject: Re: [gdal-dev] netCDF to Shapefile
From: andreasft at gmail.com
To: pcorti at gmail.com
CC: manuelrainer at hotmail.com; gdal-dev at lists.osgeo.org

I have done this but not to a shapefile direct, but into a postgis database.
Use for loops to loop through the temporal dimension, then the lon and lat as sub loops.
Then you create an insert string to input each line of data into the sql database.
In our NetCDF we have 720x360 observations spatially and 1308 temporal dimension observations.
Thats a lot of data!


Andreas



2011/3/16 Paolo Corti <pcorti at gmail.com>


On Wed, Mar 16, 2011 at 3:51 AM, Manuel Rainer <manuelrainer at 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...

Hi
I don't know what you mean with performance (maybe the time needed to
make the export or the subsequent access to them?), but as far as I
remember shapefile has a file size
limit of 2 Gb, I personally would avoid that approach.
Here PostGis seems to well suit in the scenario, but if you don't have
the possibility to access/create a PostGis infrastructure, I
personally would give a try to Spatialite.

If performance are really a concern, you could instead opt for a NoSQL
database: CouchDb has a nice spatial module [0] as far as I have
heard.
You could use the shp2geocouch approach utility [1] (first export to json with
ogr2ogr then json to couchdb) for loading your data.
Please note that if you opt for the latest, I am not sure if you will
have tools for symbology and map creation at this time, neither you
can use the GDAL API.

best regards
Paolo

[0] http://vmx.cx/blog/2009-11-17/geodata-and-couchdb.htm
[1] https://github.com/maxogden/shp2geocouch/blob/master/bin/shp2geocouch

--
Paolo Corti
Geospatial software developer
web: http://www.paolocorti.net
twitter: @paolo_corti



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