[postgis-users] Querying MapServer PostGIS layer

Thu Apr 13 08:34:47 PDT 2006

Thanks for that Steve. Would that it were that simple! I fell into that 
trap when converting the data-source from PostGIS to shapefile; I left 
the columns in lower-case. But the query template did display -- it just 
couldn't fill in table values because it didn't interpret the 
column-names as such. With the PostGIS layer I don't even get 
boiler-plate text showing on the page. The (abridged) template is:

<!-- query template -->
<html>
<head>
   <title>MapServer - ItemQuery</title>
</head>

<body bgcolor="#ffffff">

<font size="+2" face="arial,helvetica"><b>Case 1: Simple ItemQuery With 
QueryMap</b></font>

<p>

This is just a simple dump of a few attributes for an individual location
in the test suites parishes layer:

<p>

<b>Place Name:</b> [placename]<br>
<b>Qualifying Name:</b> [qualifyingname]<br>
<b>Location Type:</b> [locationtype]<br>
<b>Grid Reference:</b> [locationgridref]<br>
<b>Religious Order:</b> [religiousorder]<br>

<p>
- - - - - - - etc.

Is there a limit to the length of column names? I noticed that the above 
were truncated to 10 chars. by pgsql2shp. Any sources for debugging 
info? I've looked in the error logs, but they only seem to be recording 
parts of the app which (to my mind) are working.

Thanks again,

Dave

Stephen Woodbridge wrote:
> Dave,
> 
> Shapefile attribute columns are all UPPERCASE and Postgres/postgis 
> attribute columns are all lowercase so you need to make sure that the 
> reference to the attribute columns in your template match the case 
> expected by the data source.
> 
> -Steve W
> 
> Dave Stone wrote:
>> Please excuse if this post has been asked before; I'm new to the list 
>> and finding it difficult to locate all the hidden gems of wisdom!
>>
>> I'm having a problem with querying a MapServer layer consisting of 
>> points stored in a PostGIS table. The plan is simple enough: I'm 
>> displaying the dots together with a boundary and an annotation layer, 
>> and I want to click on a dot and have a page come up showing 
>> non-spatial attributes from the PostGIS record for that location.
>>
>> What happens when I click a dot is I get a completely blank page 
>> titled 'MapServer Message' (but no message). The relevant bit of the 
>> MapServer .map file is:
>>
>>   LAYER # query layer using the loccoords PostgreSQL table
>>     CONNECTIONTYPE postgis
>>     NAME          saint_locations
>>     CONNECTION    "user=erdb13 dbname=stdraft"
>>     DATA          "geom from loccoords using unique locationref using 
>> srid=27700"
>>     STATUS        ON
>>     DEBUG         ON
>>     TYPE          POINT
>>     TOLERANCE     25
>>     CLASS
>>       NAME        "Locations"
>>       MINSCALE    2000000
>>       TEMPLATE    "result.html"
>>       DEBUG       ON
>>       STYLE
>>         SYMBOL      "circle"
>>         SIZE        5
>>         COLOR       255 0 0
>>         OUTLINECOLOR 0 0 0
>>       END
>>     END
>>
>> This whole idea is based on an example in the MapServer tutorial 
>> (http://hypnos.cbs.umn.edu/tutorial/section3.html, choose Ex.3.1). The 
>> example works fine, so why doesn't my version?  The answer seems to be 
>> that the layer being queried in the example is a shapefile whereas 
>> mine is in PostGIS.  To test this suspicion, I amended the layer 
>> definition in the .map file as follows:
>>
>>   LAYER # query layer using the loccoords PostgreSQL table
>> #   CONNECTIONTYPE postgis
>>     NAME          saint_locations
>> #   CONNECTION    "user=erdb13 dbname=stdraft"
>>     DATA          "/var/www/html/saints/data/parish/locs"
>>     STATUS        ON
>>
>> 'locs' is a shapefile produced by dumping (with pgsql2shp) the 
>> 'loccoords' table in the first DATA statement above.
>>
>> With only this trivial change, the query template 'result.html' works 
>> as intended. But since I want to use the PostGIS functionality, I need 
>> to find out what's wrong with the first LAYER spec. above.
>>
>> Any suggestions most gratefully received,
>>
>> Dave
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> 