edge problems in shp

[Frank Warmerdam]

On Sat, 12 Feb 2005 19:28:29 +0100, Yogid <yogid at o2.pl> wrote:
> Witaj Stephen,
>
> SW> Just looking at the images is hard to tell, but it looks like you are
> SW> missing the last point of the polygons. Look specifically at polygons
> SW> with  4 sides in the openev_fw.gif and compare them to the
> SW> map_server.gif and you will see that the map_server.gif polygons are all
> SW> triangles which suggests that the final point did not make it into the
> SW> polygon. Now if you assume this is the problem the other polygons seem
> SW> to have the same issue and make more sense.
>
> SW> I can say why, but maybe the final index was stored as the count (oops,
> SW> off by one) or the loop copying the points has an off by one problem.
>
> SW> -Steve W.
>
> Thank you for your answer. I still don't known what was wrong but I
> edit layer (.shp) in open_ev and save it. When I make new map file with
> this new .shp all is ok, it is good show. Maybe wintopo save it in other
> way/format (int, double, other round count).
> Thank you one more time :]
> Daniel D.

Daniel,

Two possibilities are:
  - wintopo incorrectly sets panParts[0] to 1 instead of 0.  I think the
    modern Shapelib ignores this and would get the right values while
    the old version that mapserver users might end up missing a vertex.

 - It may be that wintopo emits shapefiles without properly closing the
   shapes but that OpenEV auto-corrects for this while MapServer does
   not.

If you can provide me one of the problem files, I would be interested
in looking a bit closer at it.

Best regards,

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