Re: [Qgis-user] Why does qgis ask grass-vector's about coordinate reference system?
[...] On Fri, 2009-01-23 at 00:00 +0100, Nikos Alexandris wrote: > * While saving the Shapefile the dialog "Projection Selector" appears, > which asks for a choice and "promises" that "The data points will be > transformed from the layer coordinate reference system". Here I selected WGS84. [...] ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] Why does qgis ask grass-vector's about coordinate reference system?
Dear all, * I opened a grass location within from qgis (based on epsg:31466) * I load a grass vector map and a dialog asking for the projection system appears (Define this layer's projection). Question 1: Why qgis "asks" about the coordinate reference system since, we all _know_ that there is one and only reference system for a GRASS location? * I did no pay attention to that so, a few weeks ago, I saved a grass vector map (projected actually in epsg:31466) as a Shapefile. * While saving the Shapefile the dialog "Projection Selector" appears, which asks for a choice and "promises" that "The data points will be transformed from the layer coordinate reference system". * I discovered today that this Shapefile obtained the wgs84 "tag" (reading the .prj file) but the spatial extent (reported by ogrinfo) was something too big to be degrees:min:sec. Question 2: Should there be a transformation or not? I think it's a bit confusing to ask for a grass-vector about its coordinate reference system. Or is it my misunderstanding? Kind regards, Nikos ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] Re: S57 map files
[sorry, I replied to the wrong list (and missed most of the thread). Thankfully Gmane does a nice job of rejoining cross-posts] Chris mostly posted what I was going to say, but FWIW here is my message to the qgis-dev list: http://thread.gmane.org/gmane.comp.gis.qgis.user/3685/focus=4887 Martin wrote: > Yes, QGIS always opens first sublayers and doesn't care about the rest. :-/ Florian: > I had no idea the S52 was actually already coded somewhere... That's > good news! Yes, it's great news. It is a huge task and I am quietly amazed at the job Sylvain Duclos has done on it. Chris: > since qgis is used extensively in preparing maps for gpsdrive is it? personally to make map tiles I use a combination of gdal tools, grass's d.out.gpsdrive module, and gpsdrive code which creates a specially crafted WMS request. > Pls allow me to encourage you. me too, Hamish ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] Save image... with wld file?
Hi! At using File/Save as Image, could it be possible to make a wld file? I know can be done with the Georefencer tool, but it would be nicer (and more exact) getting the wld file automatically done from the region display settings. By now, is there any easier/faster way of doing this than with the Georeferencer tool? Thanks Agus -- Dr. Agustin Lobo Institut de Ciencies de la Terra "Jaume Almera" (CSIC) LLuis Sole Sabaris s/n 08028 Barcelona Spain Tel. 34 934095410 Fax. 34 934110012 email: agustin.l...@ija.csic.es http://www.ija.csic.es/gt/obster ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] QgsVectorFileWriter
Hi Carson,
Le mercredi 21 janvier 2009 à 16:48 +, Carson Farmer a écrit :
> > In this way, it would be better to save in a temporary shapefile first,
> > and if the process finishes successfully, remove the destination
> > shapefile and copy the temporary shp to the new location.
> >
> hmm, I don't know about this...
> Firstly, it's only useful to do this if you're concerned about the
> initial file, but since you appear to be writing to a tmp directory,
> this probably isn't all that critical...
Sometimes I don't want to get 2 versions of a shp and select the source
shp to be overwritten. If something goes wrong and the source is deleted
first, all is lost...
>
> Secondly, this creates the possibility that if something goes wrong, you
> have TWO useless files lying about on your system (one you were trying
> to replace, and the other that didn't finish writing properly).
A simple test where if a problem occurs, we delete the tmp file...
>
> The better implementation would probably be to use the memory provider
> to create a temporary QgsVectorLayer in memory, and if the process
> finishes successfully, remove the old version and write the memory layer
> to file. Of course, this only works if you're working with relatively
> 'small' layers, if you have huge vector layers (> 500,000 features) then
> you're probably better off just writing directly to file...
>
> mem_layer = QgsVectorLayer('Point', 'layer_name', 'memory')
>
> you'll have to double check the above, this is just from 'memory' ;-)
It may be a solution :-)
>
> Carson
>
--
Lionel Roubeyrie
chargé d'études
LIMAIR - La Surveillance de l'Air en Limousin
http://www.limair.asso.fr
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