Hi,

Ryan Moquin wrote:
> So in that case, hopefully you won't mind if I pick your brain for a 
> different solution.  If I'm not able to filter in order to separate 
> entities based on a specific attribute, what other options do I have?

The features you are requesting are already prepared in the trunk 
version of OpenLayers, except for the labelling. This will be included 
in Mapbuilder, but not yet for the upcoming release -- we do not have 
enough manpower to accomplish it. Having said that, developers willing 
to contribute are always welcome.

But this won't help you at the moment. Your options are to either drop 
all the goodies that Mapbuilder gives you as an application building 
framework, and use the OpenLayers mapping library directly. Or you do 
your stuff on the server side, which is much easier than you think (and 
I will explain below why).

>   I know you said I can add a datasource and do it through geoserver, 
> but I'm trying to avoid having a separate database to keep in sync 
> with my main database.

You do not have to sync anything. Geoserver as well as Mapserver can 
connect to most database systems (like MySQL, PostgreSQL/PostGIS, Oracle 
Spatial). You can configure the server to use your lat and lon columns 
to get the geographic information from.

>   Some of my features will be changing on a fairly frequent basis and 
> it would be more expensive to have to keep updating the database on 
> top of having the client refresh frequently enough.

I guess you would persist your features to your database anyway. All you 
have to do is refresh the layer after persisting, which -- assuming that 
you might have a few hundred features -- is usually quicker if you let 
it render by Mapserver/Geoserver and just retrieve the image instead of 
doing vector rendering in the browser.

>   so if you have several entities that could be in various states, so 
> you make a featurecollection in mapbuilder for each state for each 
> entity?  Seems like a lot to manage, since you are also then stuck 
> having to use a modelmerge in order to get any interaction with the 
> different entities.  Is there anyway to change an icon for a feature 
> without writing them to a geodatabase based on an attribute?

You could set a new style using the OpenLayers API and then redraw the 
feature, also using the OpenLayers API. If you only need to do that for 
one feature at a time, you can also issue a WFS GetFeature request for 
just that feature and draw it on top of the raster image.

>   Is it expensive to write these things to a geodatabase?

You do not need a geodatabase at all, and if you would persist these 
things to your database anyway, there is no additional cost. If you just 
want to have it on the client, you can still do the GetFeature thing for 
selected features.

> Is there something I'm not considering as a best practice for this?  
> I'm a bit of a GIS rookie and am not sure what the best way to handle 
> this is, am I maybe approaching it wrong?

Think more in terms of OGC services. WMS and WFS can play together well. 
Render your map using WMS, and retrieve the features you actually want 
to work with using WFS, placing them on top of the WMS image using 
either GmlRendererOL, a WFS layer with filter.

I hope this helps. Also note that there is commercial support available 
for Mapbuilder, which also includes consulting on architectural and 
design questions 
(http://www.communitymapbuilder.org/display/MAP/Commercial+Support).

Regards,
Andreas.

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