Geodatabase tables

[Ken Lord]

Hi Steve, Frank,

Steve, If i understand it correctly, you have a route event feature
class in your personal geodatabase that you want to display in
MapServer, a product of some linear referencing work.

Please correct me if I'm wrong, but you are probably setup so that:

- you have a feature class made up of lines, your roads, which define
a route. These lines have a route ID to identify the route, and
another attribute which defines the order in which the road lines make
up the route from start to finish.
- you have an event table defining points or lengths along the line
with associated attributes, such as 'a crash happened here', 'speed
limit on this section', etc.  This table also has a Route ID that
matches the appropriate route in the feature class. This non-spatial
table has a Measure attribute that describes how far along the route
the event is if its a point, or 2 measure attributes with its start
and finish distances along the route if its a segment.

... And you would like to show these events located correctly along
your roads in MapServer, from a personal geodatabase.

ArcIMS (sorry to say that evil word) displays route events from
personal geodatabases without any problem.

Aside from having Frank wave his magical coding wand,  I would suggest
that you look into the linear referencing functions in PostGIS 1.1.1.
however the spatial SQL in your DATA string may get out a bit out of
hand and slow down the generation of your maps.

To keep the 'on-the-fly' processing to a minimum, once you have your
route events created, you might want to just convert them into actual
point / line features, regardless of the format used to hold the data.

Cheers,
Ken Lord
Vancouver BC


On 4/5/06, Frank Warmerdam <warmerdam at pobox.com> wrote:
> Steve Pashby wrote:
> > ===============================================================================
> > Thanks very much for the reply Frank.  However, my tables are not specifically
> > spatial tables (holding x,y coords), but rather they have a unique field
> > (Route_ID) that is a link to a shapefile (containing road centre-line data)
> > and each road has its own unique Route-ID. This is (i think) what links the
> > two together.
>
> Steve,
>
> I have never seen a personal geodatabase setup like this.  If you make it
> available to me I might have a look.
>
> When you speak of a "personal geodatabase", you do specifically mean this
> in the ESRI ArcGIS sense, right?
>
> It might also make sense for you to access the database via a plain ODBC
> connection to get the data out rather than having OGR treat it as a
> personal geodatabase.
>
> Best regards,
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | President OSGF, http://osgeo.org
>