[Qgis-developer] In with the new, out with the old?

Carson Farmer carson.farmer at gmail.com
Mon Mar 7 17:48:46 EST 2011

Ok, I'm getting the overwhelming feeling that people want to be able
to 'write' to memory layers. I'll try to add this functionality.
However, I really don't think this should be the 'default' or
primary/sole output type. I think what I'll probably do is simply add
'output options' to the current output file dialog, such that users
can choose memory layer (this might require some work on a more
generic vector file writer), shapefile, kml, whatever...


On Mon, Mar 7, 2011 at 10:43 PM, Chris Crook <ccrook at linz.govt.nz> wrote:
> Yes please to this option (fTools writing to a memory layer)!!
> I was thinking of coding for a couple of the fTools functions I used myself.  It would be great to have it in fTools by default :-)
> Note: I've uploaded a memory saver plugin that allows memory layers to be persisted alongside the project file (MemoryLayerSaver plugin).
> In discussing this before I've suggested that this should really be a core function .. The memory layers shouldn't disappear without warning when you save and reopen a project.  This provoked some discussion and different points of view.  For example where and in what format should the memory layer data be stored.
> I also think that if you save a memory layer to a persistant format, then at least optionally the saved layer could replace the existing memory layer (ie replace the memory data provider with the provider for the saved version and retain the symbology and z order placement).
> Perhaps replacing the provider in this way should be option whenever any vector layer is saved, as memory layers don't look different to  any other to the user.
> Moving to using the memory layers as a working layer for tools would make this a much more valuable enhancement.
> Cheers
> Chris
> -----Original Message-----
> From: Alexander Bruy [mailto:alexander.bruy at gmail.com]
> Sent: Tuesday, 8 March 2011 10:08 a.m.
> To: Carson Farmer
> Cc: Qgis Developer List
> Subject: Re: [Qgis-developer] In with the new, out with the old?
> Hi Carson
> On Mon, 7 Mar 2011 18:16:23 +0000
> Carson Farmer <carson.farmer at gmail.com> wrote:
>> - Export/add geometry columns (this can now be done quite easily from
>> the field calculator, and my version appears to have issues with
>> certain vector formats)
> Starting with r15381 Field calculator can extract X, Y and perimeter, so I think this tool can be removed
>> > BTW, I think now fTools could often avoid writing new shapefiles,
>> > just adding the new info on the existing layer instead (e.g. points
>> > in polygons, etc.).
>> > Would this be hard?
>> Not overly hard no, and there are really only a few tools that this
>> would apply to.
>> One thing I'd really like to do is add the capability to output other
>> formats besides shapefiles (I'm not a big shapefile fan these days,
>> field name limitations are a hassle). I might try move over the
>> geometry and geoprocessing tools first, as they seem to be the most
>> frequently used tools.
> Maybe it is better to create in-memory layer and let user to save it in some desired format using Save As... option from layer context menu?
> --
> Alexander Bruy
> ______________________________________________________________________________________________________
> This message contains information, which is confidential and may be subject to legal privilege.
> If you are not the intended recipient, you must not peruse, use, disseminate, distribute or copy this message.
> If you have received this message in error, please notify us immediately (Phone 0800 665 463 or info at linz.govt.nz) and destroy the original message.
> LINZ accepts no responsibility for changes to this email, or for any attachments, after its transmission from LINZ.
> Thank you.
> ______________________________________________________________________________________________________

Carson J. Q. Farmer
ISSP Doctoral Fellow
National Centre for Geocomputation
National University of Ireland, Maynooth,

More information about the Qgis-developer mailing list