Also is there an easy way to count the total number of points that are in a linestring? Cannot find the function to do so. I want to keep track of how many points are left in a linestring as I go ahead and do the simplify.
On Thu, Jun 21, 2012 at 10:43 AM, Ed Linde <edoli...@gmail.com> wrote: > Hi All, > I am building a linestring comprising of nearly 1000 points, now I want to > pick every 10th point and reduce this to a linestring of 100 points! > I will use ST_linesimplify for this, but now I am wondering if there is a > measure that shows me the "difference" between the two linestrings. > Some measure like the "sum of squared errors"... I want to know what I > lose in accuracy by discarding all these points and simplifying my > line segment. So if my line strings have (x,y) points in them, I would > like to know the differences in "y" basically. > Any ideas for a different kind of measure would be great too. I was > initially thinking of measuring the distance between each point in the > original linestring (1000 points) against the new simplified linestring > and adding their squares... would that work? Just wondering if > there is a nicer, easier way to do this in Postgis? > > Thanks, > Ed >
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