I have a string of co-ordinates that are command and space separated. 

lon,lat,alt lon,lat,alt lon,lat,alt

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What I want to end up with is an array of points where a point is [lon,lat] for passing into a specific perl module. I can of course do this with a slow loop as follows. I have left this relatively verbose to help explain what I'm doing

        my @list =  split(/[, ]/,$coords);
        my $size = @list;
        my @poly = ();

        for (my $i=0; $i<=($size-3); $i+=3)
        {
                my $lon = $list[$i+0];
                my $lat = $list[$i+1];
                my $point = [$lon,$lat];
                push (@poly, $point);
        }

[download]

Now this works fine, but I have coordinate lists of tens of thousands of points and performance is an issue as this needs to run as a web service.

I have a feeling that using map and grep I could make this much more efficient, but I can't get my head round how.

Do any wise monks have a neat and fast solution for this problem?

Thanks!

In reply to Fastest way to turn coordinate list into array by brancusi

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