[postgis-users] Postgis Simplify

[Brent Wood]

> --- Christo Du Preez <christo at mecola.com> wrote:
>
>---------------------------------
>  So Simplify is the right method forreducing the number of points? 

Yes. Some GIS's systems call the operation "generalize" instead of simplify,
but it does the same thing.

> Testing SELECT npoints(Simplify(the_geom, 80)), npoints(the_geom)
> produces: 70203, 84990. 

So about 15000 vertices could be removed from your original linestring (which
has 84990 vertices) without the new/resulting linestring having any part more
than 80 map units from the original line. 

A bit like fitting a generalised line within a 80unit buffer around the
original line, by removing superfluous vertices.

Looks like your map units are not degrees :-)

Hope this helps....


I'm not sure why your data is output in exponential format, I haven't seen that
before, maybe some format setting?


Cheers,

  Brent Wood