Re: [Maposmatic-dev] [PATCH] Make the computation of the city contours more robust

[Thomas Petazzoni]

Pulled, pushed and in production, thanks.

However, I'm also interested by explanations on this. For a city like
Meudon that was failing previously, it now works properly. However, I
have a message in maposmaticd logs saying that the coordinates are
strange.

Could you elaborate on what are these strange city contours ?

Thanks!

Thomas

Le Thu, 10 Sep 2009 23:57:19 +0200,
David Decotigny <address@hidden> a écrit :

> This should fix most of the #27413 issues. The original code was not
> robust enough to support strange city contours. This patch makes it
> more tolerant with "unusual" envelopes (those we did not foresee in
> the first place) and more verbose in case of problems.
> ---
>  ocitysmap/street_index.py |   41
> +++++++++++++++++++++++++++++++++++------ 1 files changed, 35
> insertions(+), 6 deletions(-)
> 
> diff --git a/ocitysmap/street_index.py b/ocitysmap/street_index.py
> index f24fcd3..ef1bc83 100644
> --- a/ocitysmap/street_index.py
> +++ b/ocitysmap/street_index.py
> @@ -334,7 +334,8 @@ class OCitySMap:
>          
>          return BoundingBox.parse_wkt(records[0][0])
>  
> -    _regexp_contour = re.compile('^POLYGON\(\((\S*) (\S*),\S*
> (\S*),(\S*) \S*,\S* \S*,\S* \S*\),\(([^)]*)\)\)$')
> +    _regexp_contour =
> re.compile('^POLYGON\(\(([^)]*)\),\(([^)]*)\)\)$')
> +    _regexp_coords  = re.compile('^(\S*)\s+(\S*)$')
>  
>      def get_city_contour(self, db, city):
>  
> @@ -350,21 +351,49 @@ class OCitySMap:
>                                   and admin_level='8' and
> name='%s';""" % \ pgdb.escape_string(city.encode('utf-8')))
>          sl = cursor.fetchall()
> -        cell00 = sl[0][0].strip()
> -        if not cell00: return None
> +        try:
> +            cell00 = sl[0][0].strip()
> +        except (KeyError,AttributeError):
> +            l.error("Invalid DB contour structure")
> +            return None
> +
> +        # Got nothing usable
> +        if not cell00:
> +            return None
>  
>          # Parse the answer, in order to add a margin around the area
>          prev_locale = locale.getlocale(locale.LC_ALL)
>          locale.setlocale(locale.LC_ALL, "C")
>          try:
>              matches = self._regexp_contour.match(cell00)
> -            ymin, xmin, xmax, ymax, inside = matches.groups()
> -            xmin, ymin, ymax, xmax = map(float, (xmin, ymin, ymax,
> xmax))
> -            xmin -= 1. ; xmax += 1. # Add one degree around the area
> +            if not matches:
> +                l.error("Area not conformant")
> +                return None
> +            scoords, inside = matches.groups()
> +
> +            # Determine bbox envelope
> +            xmin, ymin, ymax, xmax = (None,)*4
> +            lcoords = scoords.split(',')
> +            if len(lcoords) != 5:
> +                l.warning("Coords look atypical: %s", lcoords)
> +            for scoord in lcoords:
> +                matches = self._regexp_coords.match(scoord)
> +                y,x = map(float,matches.groups())
> +                if (xmax is None) or xmax < x: xmax = x
> +                if (xmin is None) or xmin > x: xmin = x
> +                if (ymax is None) or ymax < y: ymax = y
> +                if (ymin is None) or ymin > y: ymin = y
> +
> +            # Add one degree around the area
> +            xmin -= 1. ; xmax += 1.
>              ymin -= 1. ; ymax += 1.
>              return "POLYGON((%f %f, %f %f, %f %f, %f %f, %f
> %f),(%s))" \ % (ymin, xmin, ymin, xmax, ymax, xmax, ymax, xmin, ymin,
> xmin, inside)
> +        except:
> +            # Regexp error: area is not a "simple" polygon
> +            l.exception("Unexpected exception")
> +            return None
>          finally:
>              locale.setlocale(locale.LC_ALL, prev_locale)
>  


-- 
Thomas Petazzoni                         http://thomas.enix.org
Promouvoir et défendre le Logiciel Libre http://www.april.org
Logiciels Libres à Toulouse              http://www.toulibre.org

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