[Ottawa_users] Clipping shapefiles with ogr2ogr

[Alyre Chiasson]

Hello,

I have two shape files with the following identical prj :

GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]

I want to cut a rectangle with the following coordinates

xmin –68.9125
ymin 44.129
xmax –63.0701
ymax 48.3721

from a shapefile with the following coordinates:

xmin –69.35
ymin 43.45
xmax –50.85
ymax 60.95

The way I read it the smaller rectangle should lay totally within the 
larger. So I have tried:

ogr2ogr –spat –68.9125 44.129 –63.0701 48.3721 out.shp in.shp

The does produce a new file, however, the metadata have not changed, 
QGIS says it is the same as the original. In addition when I overlay the 
out.shp over the in.shp, I do not have a smaller rectangle within a 
larger. What I have is almost a diagonal swath retained from the 
original file with two cookie cutter holes of contour lines missing in 
the lower portion. The original shapefile contains contour lines for 
temperature. The cookie cutter holes are areas with closed polygons that 
are close to being spherical.

What am I missing here? Does the spat option do something other than 
clipping? Seemed straight forward but the results are strange.

Thanks

Alyre