[Gdal-dev] Get Line Length

[Rob McCulley]

Hi All,

 

I'm trying to write a script that will calculate the total length of a
polyline shapefile using ogr in python.  I see in the ogr documentation
that both the OGRCurve and OGRLineString class support the method
get_Length().  The problem I'm having is that I can't figure out how to
get a linestring or curve object.  Here  is what I have so far:

 

shp = ogr.Open(gpsfilelocation)

lyr = shp.GetLayer()

totalLength = 0

for i in range(lyr.GetFeatureCount()):

            ftr = lyr.GetFeature(i)

            geom = lyr.GetGeometryRef()

            length = ?

            totalLength = totalLength + length

 

At this point I could iterate through the points of the geometry and
calculate the length of each segment, but using a get_Length() function
seems much more elegant.

 

How do I access the curve or linestring class to calculate the length?

 

Rob McCulley

GIS Coordinator

County of Vermilion River No. 24

(780) 846-2244

www.vermilion-river.ab.ca

 


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