<span class="q" id="q_111f988058ea8834_5">So, can anyone explain the meaning of the first two points in
<a href="http://grass.itc.it/grass60/index.php#features" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">this feaure list</a> of grass6, where there is a direct and explicit mention to postgis?</span>
<br><br><div><span class="gmail_quote">2007/4/16, Paul Kelly <<a href="mailto:paul-grass@stjohnspoint.co.uk">paul-grass@stjohnspoint.co.uk</a>>:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Sun, 15 Apr 2007, Emanuele Conti wrote:<br><br>> Hi everybody,<br>> I'm a university student and I'm doing a thesis on the integration of grass<br>> with mysql. I found that grass has a good support for postgis and I'd like
<br>> to duplicate all the main features available for this db for mysql, which<br>> has geometry extensions (opengis compliant) and performs significantly<br>> better than postgres. I downloaded grass 6.3 cvs source code yet and I
<br><br>As I understand it the OpenGIS vector format is a lot less featureful than<br>the GRASS format (i.e. it doesn't store the topological relationships<br>between vector features, which is important for a lot of vector analyses)
<br>and thus it is debateable whether it is useful to store GRASS data in that<br>format. It would mean topology would have to be re-built from the external<br>data any time an analysis is to be done in GRASS. My understanding is the
<br>OpenGIS format is more of a quick-access format useful for displaying<br>data, but if it is to be edited, topological format is better for ensuring<br>the integrity of the data (no overlapping boundaries and that kind of
<br>thing).<br><br>As far as I can remember GRASS used to directly support storage of vector<br>geometry in PostGIS in 5.7/6.0 pre-releases, but that was removed before<br>the release of 6.0.0 final because there were problems with it. The
<br>PostGIS support was integrated by a group of final year project students I<br>think - there may also have been a paper written about it. It would<br>probably be a good idea to investigate this (e.g. download an old version
<br>of GRASS and try it out etc.) and investigate what the problems were and<br>why it was dropped, and see if you can do better with your MySQL spatial<br>support.<br><br>Off the top of my head though, I think the shortcomings of the OpenGIS
<br>vector format for spatial analysis were a major factor. But you would need<br>to read old mailing list posts from Radim Blazek for more insight.<br><br>Paul<br><br>> started to have a look to the code, but I've some questions:
<br>> - from the grass 6 features page I understood that with postGis it's no more<br>> necessary to pass through gdal ogr translation: is this true? Is there a<br>> direct db manipulation?<br>> - what part of the code implements the direct "Export/Import to
<br>> *PostGIS"*(functions as<br>> v.to.db and so on) and which directories and files should I look at?<br>> - what documentation could help me and where could I find it (I googled for<br>> technical docs oriented to grass/db integration, but I did't found much
<br>> material);<br>> - is this a project that could become part of grass in any way? How could I<br>> receive support and/or feedback when necessary?<br>><br>> I hope to read of you soon. Thanks...<br>>
<br>> --<br>> Emanuele Conti<br>> Senior Student at University ROMA TRE<br>> Department of Informatics and Automation<br>> ROME, Italy (matr. 251318)<br>> Mob: +39 328 2681070<br>> Home: +39 06 39741124
<br>> e-mail: <a href="mailto:emanuele.conti@yahoo.com">emanuele.conti@yahoo.com</a><br>> y!: emanuele_c<br>> msn: <a href="mailto:emanuele_c@yahoo.com">emanuele_c@yahoo.com</a><br>><br></blockquote>
</div><br><br clear="all"><br>-- <br>Emanuele Conti<br>Senior Student at University ROMA TRE<br>Department of Informatics and Automation<br>ROME, Italy (matr. 251318)<br>Mob: +39 328 2681070<br>Home: +39 06 39741124
<br>e-mail: <a href="mailto:emanuele.conti@yahoo.com">emanuele.conti@yahoo.com</a><br>y!: emanuele_c<br>msn: <a href="mailto:emanuele_c@yahoo.com">emanuele_c@yahoo.com</a>