[OpenLayers-Users] Coloring feateres? Where to start...

[Andrew Larcombe]

On 12 Apr 2007, at 17:18, Jeff Dege wrote:

> We're considering a new application that will use maps in a way  
> that is
> new to us, and I was hoping people here might tell me where to start.
>
> Basically, it's using a map to help visualize a set of data, collected
> by region, area, whatever.
>
> For the sake of example, let's assume we're working on counties.
> Suppose we have a set of data that is changing continually, that is
> being rolled by by county every ten minutes.  (The underlying database
> changes constantly, but we're running a process every ten minutes that
> creates a summary dataset, grouped by county.)
>
> We want to display a map that shows all the counties, color-coded
> according to one of the values in the data set, and if the user  
> selects
> a county, we want to display the rest of the values for that county  
> in a
> div or a popup.
>
> Any ideas as to where to start?

I'd use the following approach:

- create a shapefile containing the outlines  of your counties along  
with attribute fields representing your (numeric?) data
- set up an installation of mapserver to serve your mapdata as images  
as a wms server
- set up openlayers as a wms client
- use the onmapclick event in openlayers to make a query request to  
mapserver whose return can be inserted into an openlayers popup window.

That serves as an outline, hope it (or some of it) makes sense,

Regards,

Andrew

---
Andrew Larcombe
Freelance Geospatial, Database & Web Programming

web: http://www.andrewlarcombe.co.uk
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