[gdal-dev] Offset shapefile to start from prime meridian

[zetah]

Trent Hare wrote:
>
>Zetah,
>   Oops - I skipped passed the fact you were working with vectors. 
>I read "Natural Earth" and assumed the nice hillshade images they support.
>
>Converting from 180 -> 360 -> 180 is a something we often have to 
>do for planetary data. My colleague Jay (CC'd) has written an OGR script 
>to convert from 360 -> 180 but it requires OGR and Shapely. Shapely 
>is used for line and polygon intersections (to split the boundary cases 
>before shifting). Converting it to 180 -> 360 should be simple. Hopefully 
>Jay can post it for the group.
>
>Other options:
>(1) As you can see here, you might have luck using OGR if you have 
>no features that cross 0:
>http://lists.osgeo.org/pipermail/gdal-dev/2006-June/009293.html
>
>(2) ArcMap - This tool by Jeff Jeneness has a wrap boundary script:
>http://www.jennessent.com/arcgis/shapes_graphics.htm
>
>(3) For simple points, here is an older OGR example script:
>https://isis.astrogeology.usgs.gov/IsisSupport/index.php/topic,3722.0.html

Trent, thanks for you reply

I now see that translating polygons is a problem. I followed discussion linked in
first option, but result is messy as polygons are crossing prime meridian.
Unfortunately I don't have Arcmap nor my shape file has simple points.

I do have Shapely, but didn't really used it much. Once I did script to geocode 
points to countries and that's all about me and Shapely IIRC. I'll pass manipulating
vector geometries without a GUI ;)

Followed by your first reply I thought to try and convert to other vector format
and then tweak the values, but none seems applicable. I meant to use XSL
but soon gave up, after looking at the contents of any XML format produced
by ogr2ogr...