# About the width of farm tools

If I am on a 10 ° rolling slope and the width of the seeder is 4 meters, should I input 4 meters or 4 * cos (10/rad) meters？

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All path planning on every GPS system is done in 2D.

It is not possible to make lines that are both evenly spaced on the surface as well as appear straight to us when looking across the field. Mathematically the line would be straight in 3D contour space, but we humans don’t experience that space and would see crooked lines.

If one wanted to create a new system that evenly spaces lines on a 3D surface then the GPS system would need to know the contour ahead of time. That’s something the GPS system doesn’t know now, and that information is not readily available. There’s no accurate google maps for contour. You’d have to map it yourself.

You can imagine that drawing an imaginary straight line in 2D in software is much easier than processing the contour information and creating equally spaced lines in 3D.

If your field is a constant slope and you care about ever millimeter then you could use your calculated width. Make sure to use the slope angle perpendicular to travel direction.

My recommendation is to enter the true tool width and see how it goes. If there are skips then enter in a little bit of overlap until you find a happy medium. The end result is the same as your formula but adhoc and without any math.

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yes.you are right.