# AB Line for elevation rises

I am learning and reading a lot to utilize AOG. I am still new and have my hardware (LR adrusimple Kit) and have learned to draw my boundary and other basic functions. We are trying to determine if we can use an AB line to help us draw out 2/10 rises for our rice fields. we would use this to pull our irrigation levees. I know the kml file from GE can show rise, but was curious if there was a way to draw our AB on a 2/10 fall inside of one of our field files. I appreciate the help in advance.

It would take a hack in version 4. I believe @BrianTee_Admin just added the third dimension to the sections. With this data and an accurate gps, the ABLINE would be shortened and given a start, end, and a rise. Not sure how the equipment would work, but the computer could be progamed to tell how high or low it needs to be, or how far off it is now.

Thanks. As I will be pulling a levee disk to build the levee, I wonâ€™t need it to control the implement. I could even simplify it to the point where I could just follow a 2/10 rise if the gps could report it quick enough. I plan to run rtk, so I know it would be accurate enough, I just need a read out of elevation to follow and mark my line

How would aog know where to drive? Wouldnâ€™t it need a basic topological map of the entire field first? An interesting idea.

If the third dimension were included i could basically just follow the rise manually with the elevation rise even if i wasnâ€™t able to draw the ab line. if I understand you correctly @KentStuff that is coming. i would think it would be as simple as creating a border around my field and working from the lowest point to the highest point at each interval that I would want to build a levee. This link gives a basic overview of what i am trying to accomplish Riceland Foods

We donâ€™t grow rice but an example contour plot from one of our fields. This is based on a log from the Fendt VarioGuide RTK receiver. First the field is measured along straight A-B lines at some 3 to 10 metre intervals. The measurement data is processed to obtain the contour map, a kml file.

No idea how complicated it would be to pick up appropriate contour lines either to follow manually or a contour waylines for AOG. I understand in the above example the marker lines were created with assisted steering. The driver should â€śjustâ€ť see this contour map on the AOG screen.

Note, contour lines are at 2 cm elevation grid on the left of the screen, 5 cm grid on the right side. Demonstrates the accuracy of a standard RTK receiver for elevation measurements.

Yeah thatâ€™s what I was thinking, @NorthernFarmer. AOG would need to log the location and elevation every so often, which would then later be processed and used to create the contours.

I donâ€™t see how one would do what @hgn06001 is talking about with AB lines that contain elevation information. If heâ€™s going to drive manually and try to follow the elevation by noting the GPS elevation and by sight, then I donâ€™t see what that has to do with AB lines.

I think what AOG would need is simply a vertical indicator on one side. And a left right indicator on the top. You set the vertical to the current elevation (like a tare or zero button on a scale.) As you drive it will indicate how far off the elevation you are. After you have driven a few feet the roll indicator or the dual GPS could process the need for and the amount of steer needed. There would be no AB line per say just right and left and a nice line drawn when done. Would need a fairly good filter for 2 -3".

Is it obvious which way to turn based on roll to find the correct elevation? Roll in my opinion can stay constant while elevation could change.

True, but you would not drive to the right if the tractor was pitched left to get to a lower elevation. Just drive left until your elevation matches the set elevation. And as Brian says â€śrinse and repeatâ€ť. Dual GPS would be better. Quad even better. But you could do well with roll.

If I understand the riceland example right, they work as you suggest. They do not map contour lines in advance based on a survey but just start from one point and drive with the intention to keep the elevation fixed.

I have no idea about the height of these levees, how much tolerance do they allow? They try to have a levee at every 6 cm contour line. Pretty challenging in my opinion to steer at an elevation change of a fraction of 6 cm when RTK horizontal accuracy is not much better than 5 cm (perhaps a bit less when the base is this close). Not sure if I got everything right.

If I had the skill to define contour waylines for AOG, Iâ€™d still do a survey first, then derive the waylines to drive (drive manually or automatically).

Yes, Iâ€™d map the field, draw the required contours, follow the line, adjust as needed as driven. I think I saw where they were using three base stations. But I did hear the word laser in there as well???

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I wonder how they do it. If the tractor is driving straight and then the elevation starts to change, do they just turn left or right randomly and see if they can pick up a trend? Seems like theyâ€™d have to have some additional information, like maybe some kind of radar out the front of the tractor to get an idea of where a slope is that they can turn into. Or maybe have a sensor on the steering axle that detects when it pivots?

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