Shapefile questions

[Sandeep Bashyal]

On Fri, 1 Oct 2004 08:42:44 -0400, Lowell Filak <lfilak at MEDINACO.ORG>
wrote:

> The following message was sent by Sandeep Bashyal <gis at UNDPHAIS.ORG.NP>
> on Fri, 1 Oct 2004 10:35:33 +0545.
>
>> Hello,
>>
>> I have the following questions about shapefiles and mapserver:
>>
>> 1. Does Mapserver support "merged" polygons in shapefiles? E.g. arcview
>> allows you to merge two or more NON-ADJACENT polygons, such that they
>> are
>> treated as a single shape and point to the same rows in the attribute
>> table. I was wondering if mapserver supports such shapefiles with
>> merged
>> non-adjacent polygons.
>>
>> 2. Is there a way to assign shapeindex for shapes in a layer from one of
>> the fields in the attribute table (like in the mapfile or by dnamically
>> adding a layer with phpmapscript)? I have a layer with over 4000
>> polygons
>> whose attribute ID's do not correspond to the shapeindex returned from
>> query results. I need the attribute ID's to link to a external database
>> and display results.
>>
>> Any advice on an easy way to write shapeindexes into a field in the
>> attribute table would also be helpful.
>>
>> Thanks in advance.
>>
>> --
>> Sandeep Bashyal
>
> Sandeep,
>
> I don't know about #1. I, think, technically because a shape is not
> actually defined as a polygon it could actually be composed of many
> polygons. However there are many on this list more qualified to answer
> this.
> For #2. If the records in the attribute table you are trying to relate
> have a 1:1 relationship with the shapes in the shapefile then you may be
> able to add the shape index to the attribute table as a sequential
> number If the attribute records are loaded in the same sequence as the
> shapes occur. The more probable solution is have the ID as a field in
> the DBF that is associated with the SHP file and use the shape index to
> extract the ID from the DBF and then extract the attributes from the
> table.
>
> HTH
>
> Lowell
>

Thanks for the response. I was able to get the shapeindex as a feild in
the attribute table. I'm thinking of creating an sql table containing the
shapeindex and the corresponding ID (or using the dbf file itself) and
extracting the the corresponding ID's to display query results from an
external database. Is there an easier way to do this? Can I get attribute
values back into php directly from query results?


--
Sandeep Bashyal
--
   National GIS Officer
   Humanitarian Assistance Information System (HAIS)
   United Nations (NEP/01/008)
   UN House, Pulchowk
   G.P.O. Box 107
   Kathmandu, Nepal
   Tel: (+977) 01 5543957
        (+977) 01 5554304
   Cell:(+977) 9841270854
   Fax: (+977) 01 5528059
--------------------------------------------------
mailto:gis at undphais.org.np
mailto:sandeep at earthmapping.com
http://www.undp.org.np