[mapserver-users] PostGIS wildcard expression and blank map -- SOLVED

Johan Forsman Johan.Forsman at LA.GOV
Wed Dec 2 13:09:06 EST 2009


Indeed not on purpose! Corrected and all is well with the map display. Egg on my face, thanks Paul.

The original file that points to shapefiles have it correct, I must have inadvertently turned it around when I was working on the LIKE version of the EXPRESSION statement. Stare at your own work long enough...

Now back to trying to determine why php-cgi.exe crashes when I query the PostGIS data.

Thanks again,
Johan.

-----Original Message-----
From: Paul Ramsey [mailto:pramsey at cleverelephant.ca] 
Sent: Wednesday, December 02, 2009 11:46 AM
To: Johan Forsman
Cc: mapserver-users at lists.osgeo.org
Subject: Re: [mapserver-users] PostGIS wildcard expression and blank map

The usual regex for "starts with P" is /^P/ but your is backwards, is
that on purpose?

P

On Wed, Dec 2, 2009 at 9:27 AM, Johan Forsman <Johan.Forsman at la.gov> wrote:
> Hello All:
>
> I have a vexing problem where wildcard expressions in my mapfile return blank maps (tested directly in the browser address bar) when queried against a PostGIS database, but work perfectly against a shapefile.
>
> There are no errors indicated in the log. In fact, the log indicates that it finds all the data alright:
>
> (snip)
> [Wed Dec 02 11:02:28 2009].890000 msPostGISLayerWhichShapes got 20691 records in result.
> (snip)
> [Wed Dec 02 11:02:28 2009].921000 msPostGISReadShape called.
> [Wed Dec 02 11:02:28 2009].921000 msPostGISReadShape: [welluse] "P-R"
> [Wed Dec 02 11:02:28 2009].921000 msPostGISReadShape: [newid] "001-1060"
> [Wed Dec 02 11:02:28 2009].921000 msPostGISReadShape: [index] 4
> [Wed Dec 02 11:02:28 2009].921000 msPostGISReadShape: [shape] POINT (577278.4106000000600000 3355380.4495999999000000)
> [Wed Dec 02 11:02:28 2009].921000 msPostGISLayerNextShape called.
> (snip)
>
> There are indeed 20691 records in the table. The "welluse" field contains entries that start with one of the letters "P", "N", "T", "Z", or "O", and are classified based on these letters.
>
> The mapfile contains the following relevant lines:
>
> (snip)
> CLASSITEM "welluse"
>  CLASS
>    NAME "Public"
>    EXPRESSION /P^/
> (snip)
>
> Using
>
>        EXPRESSION /P^/
>
> returns nothing from PostGIS, but the proper results from the shapefile (all records that start with the letter "P" in the field "welluse"). There are no errors returned from PostGIS, just a blank map and entries as shown in the log snippet above.
>
> Using
>
>        EXPRESSION /P-R/
>
> returns the correct results (all records with "P-R" in the field "welluse") from PostGIS and the shapefile.
>
> I have tried crafting an expression using the SQL "LIKE" operator, e.g. various forms of
>
>        EXPRESSION ([welluse] like 'P%')
>
> which usually works in SQL, but appears to not be supported in this instance based on all the syntax errors in the log after trying it, hence trying the regex above.
>
> I am certain I am missing something obvious, but I would nevertheless appreciate your advice. I am trying to migrate the point data to PostGIS to improve on the query performance which is too poor using shapefiles on our humble server. Then I may be back to ask why php_cgi.exe crashes in ntdll.dll every time I try to query a dataset in PostGIS but works fine (but too slow) when using shapefiles, but I'll leave that for a later time.
>
> I am currently using the MS4W beta from earlier this autumn, version 3 I think. It shipped with MS 5.4.2, but I have updated the to the RC1 version of MS 5.6 while looking for a solution to the php crashes (no difference).
>
> Thanks in advance,
> Johan.
>
> ----------------------
> Johan Forsman
> Geologist
> Safe Drinking Water Program
> Louisiana Department of Health and Hospitals
> Office of Public Health
> Telephone: 225.342.7309
> Telefax: 225.342.7303
>
>
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>


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