Valentine Artist Boyd Elder Sets a Contour Chris Gill on January 9, 2010 All patterns are plowed on contours which are reset every 200 feet. The device shown here is an optical transit. We now use a laser transit which can be operated by one person and which is much faster. Category: HABITAT RESTORATION Tag: habitat restoration, SubSoiling, Yeomans Keyline Post navigation Previous: Previous post: Plow Design. Timing of Treatments. Possible Seed.Next: Next post: Chris Gill to TPWD Executive Director Carter Smith on Elk Eradications Share this:EmailPrintTwitterFacebookGoogleLinkedIn Posted by Chris Gill All Posts Leave a comment Leave a Reply Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website Notify me of follow-up comments by email. Notify me of new posts by email.