[GRASS-user] Smoothing unclosed contour

GRASS GRASS user
1

Hi list,

Help me please! I have a set of unclosed contours, which are created from raster cropped by the mask.
After smoothing with “v.generalize method=boyle look_ahead=5” I have obtained smooth, but duplicated contours.

http://www.image-share.com/ipng-1014-170.html
http://www.image-share.com/ipng-1014-171.html

How can I fix it?

Best regards, Dmitriy

2

Dmitriy Tyugaev wrote:

Hi list,
Help me please! I have a set of unclosed contours, which are created from
raster cropped by the mask.
After smoothing with "v.generalize method=boyle look_ahead=5" I have
obtained smooth, but duplicated contours.
http://www.image-share.com/ipng-1014-170.html
http://www.image-share.com/ipng-1014-171.html
How can I fix it?

That looks like duplicate contours, something could have gone wrong
when extracting contour lines. You can try to clean the contours first
by breaking lines at intersections, then removing duplicates and
finally building polylines. Then try to smooth them again.

v.clean tool=break,rmdupl type=line
v.build.polylines cats=first
v.generalize

HTH,

Markus M