Assign special dbf to shapefile

[Ken Lord]

This definately calls for PostGIS, and I'm sure it would process the
request much faster.

But,

Why not use the join object in mapserver?

http://mapserver.gis.umn.edu/doc44/mapfile-reference.html#join

Or is this join system, that was broken i think after mapserver 3.4,
still not functional? ... and if it is still not functional why have
the instructions remained in the current documentation for the last 2
years+ ... since at least mapserver 3.6?

There is another option:

Don't join the data on-the-fly. Instead when the user queries the
airport, have a link parsed in the query results that when followed
displays the attribute data you want based on the query results
returned. ... A little ASP works wonders here to take a mapserver
query result and query another database with it.

Cheers,
Ken

On Fri, 7 Jan 2005 10:22:02 -0500, Stephen Woodbridge
<woodbri at swoodbridge.com> wrote:
> The only way that I know of to do runtime joins in mapserver is to use
> PostGIS. You might be able to do something with gdal, but I think it is
> very slow.  I have requested support for runtime shapefile joins to
> either DBF or MySQL multiple times and nothing has happened in that
> direction. Basically, it would be very slow because for each object in
> the shapefile, you would have to scan the whole DBF file, because there
> are no indexes support for DBF files, or the developers would have to
> build DBF indexing support into mapserver. For Mysql, you could index
> the columns, but you would still need to make a separate query for every
> object in the shapefile.
>
> In PostGIS, since you have all the data in the database to start with
> you can make one query for the layer and do the join in that query, then
> you only have to fetch back the objects to render.
>
> -Steve W.
>
> Holger Floerke wrote:
> > Hi Jacob,
> >
> >
> >>Why would you not want to join them?
> >
> > If the information I would like to present is evaluated at runtime, I have
> > to produce a full set of ".shp", ".dbf", "sbx", "sbn", and ".shx" files. The
> > shapes always stays the same, but the data is extracted from a database on a
> > user's query. I would like to save space by not copying the shape
> > information every time.
> >
> >
> >>unless if you created a join on a dbf, and accessed it separately.
> >
> > Is it possible to join external data sources (one or more dbf-files or
> > oci-sources) to shape files at runtime with the mapserver-api?
> >
> > HolgeR
> >
> >
> > Jacob Delfos schrieb:
> >
> >
> >>Holger,
> >>
> >>Correct me if I'm wrong, but that would be redefining the definition of
> >>a shapefile. As far as I know, a "shapefile" is not the .shp file, but
> >>the collection of ".shp", ".dbf", "sbx", "sbn", and ".shx" files. I
> >>think you'd have to seriously hack the source of mapserver to do that,
> >>unless if you created a join on a dbf, and accessed it separately.
> >>
> >>Why would you not want to join them? If you have access to MS Excel, it
> >>would be as simple as copying a column across. No doubt other software
> >>can do the same thing. You would have access to both attributes in one
> >>shapefile. What is the actual problem that causes you not to want to
> >>have two shapefiles, and not to want to join the attributes?
> >>
> >>regards,
> >>
> >>Jacob
> >>
> >>
> >>-----Original Message-----
> >>From: UMN MapServer Users List
> >>To: MAPSERVER-USERS at LISTS.UMN.EDU
> >>Sent: 1/7/2005 9:03 PM
> >>Subject: [UMN_MAPSERVER-USERS] Assign special dbf to shapefile
> >>
> >>Hi all,
> >>
> >>am I able to assign a special dbf-file to a shape file? For example
> >>rendering the 'airports.shp', but using data from
> >>'airports_passengers.dbf'
> >>and not from 'airports.dbf' (ensuring the correct order for the
> >>shape-information-mapping). Or another example, render some area shapes
> >>on
> >>the one hand with popuplation data and on the other hand with
> >>unemployment
> >>data without integrating both data sets into the dbf of the shape file
> >>and
> >>without producing two different shape-files. I use php-mapscript and
> >>mapserver 4.4.
> >>
> >>HolgeR
> >>
> >
> >