[gdal-dev] weeding out x,y,z points

nicholas.g.lawrence at mainroads.qld.gov.au nicholas.g.lawrence at mainroads.qld.gov.au
Wed Feb 25 23:56:24 EST 2009

> nicholas.g.lawrence at mainroads.qld.gov.au wrote:
> > A client has a very large (millions of records) ascii file consisting
> > solely of x,y,z co-ordinates.
> >
> > They would like to reduce the number of records by weeking out points
> > are too close to each other.
> >
> > Can GDAL or OGR weed out 3D points based on proximity to each other?

> A job for GMT's blockmean or blockmedian.

> Joaquim Luis

Okay, I downloaded the Manpages.

My initial reading is that blockmean and blockmedian work by averaging
the values.

My client says that they want the resulting data points to be
a subset of the original data points, that is the process should
delete points, not re-calculate new ones that are an average.

Is this still do-able? Is there a specific option I should
be looking at?


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