Quoting Stuart Blair <stublair@anonymised.com>:
> Dear Chris,
>
> Thanks for getting back to me I can't express how much I appreciate
> it! I;ve
> had had a look at the links you sent and got a bit more confused i
> think-
> sorry!!
Hrm. This sort of begs a definitive newbie user introduction. Maybe
I'll start working on that.
GeoConnections has put together an online training manual that may help
here: http://www.geoconnections.org/publications/training_manual/e/index.htm
It talks in terms of the Canadian Geospatial Data Infrastructure, but it's
largely based on the OGC standards.
I find it is helpful to think of this architecture in terms of 3 layers:
1. the data layer: this is where shapefiles, PostGIS, ArcSDE, etc. live.
Geographic data comes in many formats and there are many ways to
create/manage your data.
2. the service layer: provides an open and standard way of accessing the
data layer. This is where the OGC specs for WMS/WFS (and
geoserver/mapserver/other WMS/WFS products) come in. The service layer
provides an abstraction to the data layer so that it doesn't matter what
format your data is in, you have a _standard_ way to access it.
3. the application layer: this is where mapbuilder/uDig/mapbender/etc. live.
These applications know how to call and interact with the service layer. In
the WFS transaction case, you can also pass information back down through
the service layer to modify the data layer. The web-based software packages
mentioned here provide tools and widgets that you can use to embed mapping
into your application with functions like zoom/pan, selecting layers, etc.
It is up to the application designer to tailor the app so that your message
gets across to your target audience.
For the applications, another important specification is the Web Map Context
document. This is a standard way of encoding (in XML) what layers make up
your map. So for example you could have base map street layers that come
from one WMS, overlay that with the crime stats layer from your geoserver
instance, an overlay that with a age of the population(?) layer from a third
server. You pass this context document to the application to tell it what
layers to show in the map, or email it to your friend an have them open up
the same map in their own map viewer.
Hope this helps,
Mike Adair
(a mapbuilder developer)