I am researching about shapefiles. I am not able to understand the usage of polyline Z parameters.

I have searched the internet but I didn't come across any example where this parameter is being used.

Please help me to understand this parameter better?

  • Welcome to GIS SE! I recommend that you extend your internet search to Wikipedia which has a useful Shapefile page that mentions the Z (three-dimensional) type. – PolyGeo Aug 31 '14 at 9:45
  • thanx PolyGeo.I have read the wiki page and I am unable to find some examples where this parameter has been used. That's why I posted here. – dipz Aug 31 '14 at 16:20

Z parameter is used to store a third coordinate in your geometry (usually the elevation). Having a polyline Z allows you to store this value for each vertex of your line, contrary to storing an average constant value in an attribute table (one value per vertex vs one value per line).

It is used for different 3D analysis such as TIN building or profile extraction. Note also that you can measure the true 3D lenght instead of the projected length. Finally, 3D snapping can be used as an advanced editing feature.

  • Thanks radouxju for the reply. Can you please refer me to some example as am not able to find this parameter in any shape file. This will help me better to understand and create the shapefiles. – dipz Aug 31 '14 at 16:17
  • you can find an example from the SRTM water body data dds.cr.usgs.gov/srtm/version2_1/SWBD/SWBDwest – radouxju Aug 31 '14 at 16:30

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