Hi all,<div><br></div><div>This is a very interesting idea indeed. My personal preference would be a zip file with the xml file inside for the project file, and other files for the extra stuff eg memory layers, styles, images.</div>
<div><br></div><div>So:</div><div><br></div><div>MyProject.zqgs <- zip file with custom extension.</div><div> |</div><div> |> MyProject.qgs <- Project file</div><div> |</div><div> |> MyProectMemory.sqllte <- <meta http-equiv="content-type" content="text/html; charset=utf-8">spatialite database</div>
<div> |</div><div> |> Other files, maybe some project specific qml files, images etc</div><div><br></div><div>My reason for using just a plan zip file with everything in it would be; it makes it easier to get to the project file if needed; allows for as many items as needed in the future; don't need anything special to view the content. </div>
<meta http-equiv="content-type" content="text/html; charset=utf-8"><div><br></div><div>As far as I am aware Steam, the gaming engine, does the same kind of thing with its game files.</div><div><br></div><div>Just my 2 cents worth. </div>
<div><br></div><div>- Nathan<br><br><div class="gmail_quote">On Sat, Dec 4, 2010 at 1:35 PM, Chris Crook <span dir="ltr"><<a href="mailto:ccrook@linz.govt.nz">ccrook@linz.govt.nz</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi Martin and list readers<br>
<br>
Interesting idea! This would certainly achieve my main goal, which is to have the project reopen with the same information in as when I closed it.<br>
<br>
I agree that saving the the XML file could be cumbersome - even though these are only memory provider layers I guess they could get quite big. And very good point about loading from the DOM.<br>
<br>
Another way to achieve a similar result could be to embed the project file in the spatialite database? That would make the memory provider data easier to use - basically it just becomes a spatialite provided layer. The project itself becomes harder to manually edit, if you wanted to do so. However it could easily be exported to a separate file if that is required. And the whole thing could still be zipped if you wanted to.<br>
<br>
I don't see these options as exclusive.<br>
<br>
Look forward to comments,<br>
Chris<br>
<br>
________________________________________<br>
From: Martin Dobias [<a href="http://wonder.sk" target="_blank">wonder.sk</a>@<a href="http://gmail.com" target="_blank">gmail.com</a>]<br>
Sent: 03 December 2010 11:01<br>
To: Chris Crook<br>
Cc: <a href="mailto:qgis-developer@lists.osgeo.org">qgis-developer@lists.osgeo.org</a><br>
Subject: Re: [Qgis-developer] Memory data provider persistence<br>
<div><div></div><div class="h5"><br>
Hi Chris<br>
<br>
On Mon, Nov 29, 2010 at 8:54 PM, Chris Crook <<a href="mailto:ccrook@linz.govt.nz">ccrook@linz.govt.nz</a>> wrote:<br>
> Hi All<br>
><br>
> I'm looking for ideas/suggestions/comments on the memory data provider.<br>
><br>
> A while ago I raised a ticket <a href="http://trac.osgeo.org/qgis/ticket/2487" target="_blank">http://trac.osgeo.org/qgis/ticket/2487</a>, the essence of which is that if you save and reload a project nothing should have changed, but if you have a layer supported by a memory data provider then its contents get lost.<br>
><br>
> In the ticket I suggested that the user should be warned on saving, and the layers not included in the project file. That way at least you don't end up with empty layers.<br>
><br>
> I'm now coming to a different point of view, which is that it would make much more sense to save the data for the memory provider into the project file.<br>
<br>
Having a possibility to save the data into a project would be a nice<br>
feature. However I think that saving the features directly into the<br>
XML project file wouldn't scale well with the amount of data. It can<br>
work well for small datasets, though I'm afraid that it will fail with<br>
a lot of data. One reason is that the project file would get pretty<br>
big due the verbosity of XML, another problem would be with the memory<br>
footprint and parsing speed - we're using DOM.<br>
<br>
I have started to think about a more radical step: to allow the<br>
projects to be not only XML files, but additionally they could be e.g.<br>
ZIP files with project XML file inside and optionally some more files.<br>
AFAIK OpenDocument format (used in OpenOffice) does this too.<br>
Internally QGIS could ask the user and convert his data from memory<br>
provider (or any other provider) to e.g. spatialite database that<br>
would be included in that project ZIP file.<br>
<br>
This would involve the following changes:<br>
- implement reading and writing of compressed project files (using zlib)<br>
- write a generic QgsVectorLayer -> SpatiaLite export class (similar<br>
to QgsVectorFileWriter or an extension of it)<br>
- add support to read/write "embedded" layers<br>
<br>
This would also enable a nice feature to let QGIS pack all data into<br>
one (compressed) file and pass just that file around!<br>
<br>
What do you (and others) think of such solution?<br>
<br>
Regards<br>
Martin<br>
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