error message

[Ed McNierney]

John -

TILEINDEX is a way to combine multiple homogeneous data sets into a single data set.  All the data needs to be of the same type - for example, if you tried to group the counties and the roads into a single TILEINDEX layer, would that layer be TYPE POLYGON or TYPE LINE?  And you'd have no individual control over symbology among the different types.

TILEINDEX is useful for a single set of data that has been broken up into multiple files; all the individual files should be essentially identical, other than the fact that they represent subsets of the entire set differing only in the geographic area covered.

        - Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of John Bolster
Sent: Tuesday, September 21, 2004 12:46 PM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] error message

Thanks Steve,

I have various layers of tiger/line data organized into one directory per county and I've been trying to make one tileindex for the whole thing. Based on what you're saying, do I need to run tile4ms separately on each different type of layer, so that I end up with a tileindex for the counties, one for the roads, one for the places, etc.?

John

> -----Original Message-----
> From: Stephen Woodbridge [mailto:woodbri at swoodbridge.com]
> Sent: Tuesday, September 21, 2004 10:22 AM
> To: John Bolster
> Cc: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] error message
>
>
> John,
>
> The way tileindexes work is the you group a bunch of files into a
> virtual layer. All the files must have the same dbf columns defined in
> them and defined in the same order. This is because mapserver reads
> the attribute layout of the first file it opens and uses that as the
> template for all files in the virtual layer.
>
> So if the first file had attribute columns [A, B, C] and some other
> file had [D, E] or [B, C, A] or whatever it would cause problems for
> mapserver. If you ask mapserver to CLASS on C, it translates that to
> column 3 and then tries to read column 3 from the [D, E] and gets an
> error, or gets column A from [B, C, A] file, etc. This was causing a
> lot of problems for people that did not understand the inner workings
> of mapserver, so this check was added to prevent people from doing bad
> things and not knowing about it.
>
> Some version of dbfdump will display the column definitions of you
> files. You either have some that have a different definition like a
> different version of the file, or you are picking up some files that
> are not compatible with the first file you add to the index.
>
> Hope this helps,
>    -Steve W.
>
> John Bolster wrote:
>
> > Hello,
> >
> > Does anyone know what "DBF fields do not match" means in the output
> > from tile4ms?
> >
> > Do they not match to one another, or to a certain way they're
> meant to be,
> > or to the shapefile, or what? The files were created with
> tgr2shp so I don't
> > see why they should be bad. And what would I do about this--I
> can't imagine
> > I'm the only person to whom this has happened.
> >
> > Thanks for your help,
> > John Bolster
> >
>
>