[GRASS-user] r.in.wms failure

Hamish hamish_b at yahoo.com
Thu Jul 9 04:14:45 EDT 2009


Massimo wrote:
> > I'm tring to use r.in.wms on mac osx leopard using grass64
> > (binary version) this the log :
> > 
> > GRASS 6.4.0RC5 (lonlat_pg):~ > g.region res=30 -ap
> > projection: 3 (Latitude-Longitude)
> > zone:       0
> > datum:      wgs84
> > ellipsoid:  wgs84
> > north:      60N
> > south:      30N
> > west:       0
> > east:       30E
> > nsres:      30
> > ewres:      30

Hamish:
> umm, your resolution is set to 30 degrees and so it is just
> requesting a single cell. probably not what you want.


if you were trying to use a 30m resolution that is ~ 1" aka 0:00:01.

but that is in total a 108000 x 108000 raster map, which is a) probably
too big a map for your computer to handle well, b) too many tiles for
r.in.wms to handle well, and c) rather abusive of their poor overloaded
WMS server.


Please read the top statement on the OnEarth WMS web page.
  http://wms.jpl.nasa.gov/

It reads:

"ATTENTION:

Due to server overloading, client applications are strongly advised to use the existing tile datasets wherever possible, as described in the Tiled WMS or Google Earth KML support

Frequent and repetitive requests for non-cached, small WMS tiles require an excessive amount of server resources and will be blocked in order to preserve server functionality. The OnEarth server is an experimental technology demonstrator and does not have enough resources to support these requests.
*An alternative solution already exists in the form of tiled WMS*
While sets of tiles with different sizes and alignment can be added when needed, for large datasets the duplication of storage, processing and data management resources is prohibitive."


If they notice that these huge requests are coming from GRASS software
it is rather bad karma for us...



cheers,
Hamish



      



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