[mapserver-users] Calculate length!

[Rahkonen Jukka (MML)]

Hi Lars,

You should not underestimate GDAL.  Read http://www.gdal.org/ogr_sql_sqlite.html and look at this:

ogrinfo -dialect sqlite -sql "select st_length(geometry) from line_demo limit 5" line_demo.shp
INFO: Open of `line_demo.shp'
      using driver `ESRI Shapefile' successful.

Layer name: SELECT
Geometry: None
Feature Count: 10
Layer SRS WKT:
(unknown)
st_length(geometry): Real (0.0)
OGRFeature(SELECT):0
  st_length(geometry) (Real) = 638.237633730745
OGRFeature(SELECT):1
  st_length(geometry) (Real) = 32.7179011265525
OGRFeature(SELECT):2
  st_length(geometry) (Real) = 4399.43983906202
OGRFeature(SELECT):3
  st_length(geometry) (Real) = 480.395511976145
OGRFeature(SELECT):4
  st_length(geometry) (Real) = 311.309421824364
-Jukka Rahkonen-


Schylberg Lars wrote:

As far as I know there is no length function in Mapserver.
The only geometry function to use in Expressions is area(shape).
OGR sql doesn’t provide that either as far as I can see in the documentation.

So the solutions might be to convert your KML data to  sqlite or postgis where such functions are available.

The length of a string (number of characters in the string) can be found in OGR sql with the length function,
but I am assuming You are looking for the geometric length of the linestring.

/Lars

From: mapserver-users-bounces at lists.osgeo.org<mailto:mapserver-users-bounces at lists.osgeo.org> [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of alok mathur
Sent: den 13 mars 2015 07:01
To: mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org>
Subject: [mapserver-users] Calculate length!

Hi,

I want to calculate the length in mapserver. Is it possible. Means i have a linestring and i want to know the length for it.
Also not could be suggest me how to do it.

I am using data source to mapserver as KML.

Thanks!

--

Alok Mathur
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