Hmm. With a fresh ogr2ogr from svn, I am running into this error:

ERROR 6: GEOS support not enabled.
ERROR 6: GEOS support not enabled.

Simply adding the configure option --with-geos=yes doesn't help. The configure output is:

checking for geos-config... /home/peifer/local/FWTools/bin_safe/geos-config
checking for GEOS version >= 2.2.0... yes
checking for GEOSversion in -lgeos_c... no

Any hint how to fix this?

Hermann

Even Rouault wrote:
Selon Hermann Peifer <[email protected]>:

I've finally added a new switch to ogr2ogr : -wrapdateline. See
http://trac.osgeo.org/gdal/ticket/3158

Even,

Thanks for the possible algorithm.... but to be honest: some sort of
command line switch would be /somewhat more handy/, for non-programmers
like me.

Hermann

Even Rouault wrote:
Selon Hermann Peifer <[email protected]>:

I think this should be prefectly doable with some code/script just using
OGR
API.

Here's a possible algorithm :

1) Create a new empty WGS84 shapefile
1) Loop over features in the source shapefile (the one after reprojection
to
WGS84)
2a) If the polygon has points with longitudes both near 180° and near
-180°,
create a duplicate temporary polygon and add 360° to the negative
longitudes.
Compute the interescection with Geometry.Intersect (you need GEOS support)
of
that polygon with POLYGON((0 90,180 90,180 -90,0 -90,0 90)) and with
POLYGON((180 90,360 90,360 -90,180 -90,180 90)). For the second
intersection,
substract 360° to the longitudes in order to get again longitudes in the
[-180,180] range. Finally, write 2 new features into the output shapefile,
or
better, just one with the geometry being a multipolygon with the 2 parts.
2b) Otherwise, just copy the original feature into the output shapefile

Best regards,
Even


Eric,

I can't help much apart from confirming that the same happened to me
when trying to reproject Russia from LAEA to WGS84.

My "solution" was to ask a colleague, who is using ESRI products to do
me a favour... :-(

Hermann


Eric Muller wrote:

I am trying to reproject  shapefiles that represent Russia (from

http://wagda.lib.washington.edu/DATA/geography/world/russia/download.html)
from the original:

    The map is Albers equal-area projection Clarke spheroid of1866 with
    the first standard parallel 46 00 0.000, the second standard
    parallel 73 00 0.000, the central meridian 84 00 0.000. The latitude
    of the projection's origin is 60 00 0.000.  Units -- meters.

to lat/long WGS84. I use the following command:

ogr2ogr \
    -s_srs '+proj=aea +ellps=clrk66 +lat_1=46.0 +lat_2=73.0 +lat_0=60.0
+lon_0=84.0 +units=m +no_defs' \
    -t_srs '+proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs' \
    rs_polbnda_${f}.shp rus${f}.shp

I would like polygons that cross the 180 degree longitude to be split.
It there a way to ask ogr2ogr to do that? What is the recommended way to
do it, if not?

Thanks,
Eric.


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