[Mapserver-users] Complex querying PostGIS Layer

Thu Jan 16 16:06:50 EST 2003

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Hi guys,

=20

I need to perform a complex query on a PostGIS layer in PHP MapScript
and I=92m a little unsure which part should handle the query PostGIS or
MapScript. The query logical is shown below:

=20

Select all the polygons in layerX that are intersected by featureA in
layerZ=20

where layerX=92s type field equals =93ROAD=94

=20

LayerX at the moment is always a polygon but in the future may become a
line or point. layerZ could be either point, line polygon but featureA
will only every be one feature.

=20

In PostGIS I believe you can send both the spatial query and the
attribute query in one SQL statement using a WHERE clause. Correct?=20

=20

With MapScript how would the query work? Would I basically need to run
two queries, the spatial part and then the attribute part (or vise vera)

=20

Thanks,

=20

Benjamin Wragg

=20

=20

=20

=20

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<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Hi
guys,</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

I
need to perform a complex query on a PostGIS layer in PHP MapScript and =
I&#8217;m
a little unsure which part should handle the query PostGIS or MapScript. =
The
query logical is shown below:

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Select
all the polygons in layerX that are intersected by featureA in layerZ =
</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>where
layerX&#8217;s type field equals &#8220;ROAD&#8221;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

LayerX
at the moment is always a polygon but in the future may become a line or =
point.
layerZ could be either point, line polygon but featureA will only every =
be one feature.

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

In
PostGIS I believe you can send both the spatial query and the attribute =
query in
one SQL statement using a WHERE clause. Correct?

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

With MapScript
how would the query work? Would I basically need to run two queries, the
spatial part and then the attribute part (or vise =
vera)

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Thanks,</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>Benjamin
Wragg</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></p>

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