[OSM-dev] [ GSOC ] Mapnik Stylesheet editor

Raghu Ram raghuram.nadiminti at gmail.com
Sun Mar 30 12:23:13 BST 2008


On Sun, Mar 30, 2008 at 4:11 PM, Martijn Pannevis <openstreetmap at panman.nl>
wrote:

> Hi.
> I'm a big proponent of a WYSIWYG mapnik editor; I wrote a SWYG editor as
> a start (where you can edit the XML, and see the result), as linked on
> the SoC wiki page.
> In your description you don't talk about whether you want to make this a
> desktop app, or an online tool.


  I was talking of a desktop application(A Qt based one). I donot completely
agree to the fact that we should go with an online tool. The simple problem
is rendering our own data. For example you have got a nice shape file that
you want to render. You simply cannot do that. Setting up mapnik is not
really complex. What is more complex is setting up OSM data in postgis. To
solve this issue, I propose a simple solution, a http mapnik rendering
server that provide two capabilities.
1) GetLayers
2) GetMap

A GetLayers request returns the list of layers that are available in the
server( This could just return the part of the xml that contains the list of
styles in the mapnik stylesheet). And a GetMap request returns a rendered
tile image based on a stylesheet.

Users who just want to render online would just use this protocol to do the
styling. Not much of additional code is required in the frontend desktop
application as the styling code is the same for both the things. The server
is almost the same as the one that you have. The additional GetLayers
request has to be added to your server code. Does all this sound ok to you
?? or am i talking too abstract .. ?


>
> I would propose to make this an online tool: With my tool I have seen a
> small thousand renders so far. I'm really in favor of making maps easier
> to generate, but currently installing the necessary components to start
> rendering stuff are at least as difficult as editing the mapnik XML. To
> get a tool that laymen can use, either there has to be an easy "OSM
> installer" package (something I don't see happening in the near future),
> or it has to be preinstalled on a server, where everybody can access
> your tool. Even if such an installer would exists the barrier of entry
> would be much larger than just browsing to an online tool.
> This would mean the GUI will have to be developed in either HTML/JS,
> Flash or (not my favorite, but certainly an option), Java.
> I'm in big favour of such a tool, and if there is anything I can help
> with, I'm more than open for it.
> Kind Regards,
> Martijn Pannevis.
> Btw: I can't look at your example: could you make a screenshot and place
> it somewhere?
>
> Raghu Ram wrote:
> > Hi all,
> >  I am RaghuRam, a 4th year student in the department of Computer
> > Science and Engineering, IIT Kharagpur. I have been working  since an
> > year on Mobile GIS and Map rendering stuff as a part of my BTech
> > project.  I am really awed at the amount of work being done
> > voluntarily in the OSM community. Especially, maps generated using
> > Mapnik from OSM data are very beautiful.  I have been trying to come
> > up with my own slippy map for the Navteq LBS challenge using mapnik.
> > There are some issues that I faced in doing so and would like to
> > address them during my proposal. Sorry, but to be frank, Mapnik
> > Stylesheets are too complex to write and edit. Coming up with a new
> > mapnik style sheet for some data is difficult and time consuming, not
> > to say, nearly impossible for a beginner who has little idea of GIS
> > and stuff. Though there is a program called "viewer" in the mapnik svn
> > that helps in viewing Mapnik Style sheets, its very naive. It lacks
> > the main functionality of working like an editor.
> >
> >   What I propose is a WYSIWYG <http://en.wikipedia.org/wiki/WYSIWYG>
> > editor for Mapnik stylesheets. Users can create , load and save
> > stylesheets. Once a stylesheet is loaded one can add layers to it.
> > Users can choose from one of the supported Data backends like
> > shapefile, postgis etc.. and provide the necessary information like
> > server address,user name,password.. to finish off the layer creation.
> > Once a layer is created one should associate a style with it. The
> > application should be intelligent here to make it easy for the user.
> > It should connect to the corresponding datasource and retreive the
> > features. Now the user creates a style corresponding to the layer.
> > Style creation would be driven based on the features of the
> > datasource. Users can add filters and select properties of the
> > point,line and polygon symbolizers.
> >
> > Here is the link
> > <http://raghuram.nadiminti.googlepages.com/prototype.tar.gz> to the
> > simple ui form designed in QT, resembling mostly the viewer in the
> > mapnik svn.
> >
> > Waiting for your comments...
> >
> >
> >
> > ------------------------------------------------------------------------
> >
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> >
>
>
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