November 11, 2016 06:13PM
I was bringing in some Manure application data for a farmer into FarmWorks. They are using a Raven controller hooked to a PF3000 with an AutoFarm GPS system. Quite the blended machine. The GPS is on the tractor and the application point is 40 feet behind that. If I look at the Topography map, (this is an RTK system so elevation is very accurate), I can see that the X,Y, and Z are mapping out perfectly as I get a very smooth Topography map as shown below. So the system appears to be recording the positions correctly.

http://drive.google.com/uc?export=view&id=0B3oZAe8v-JSxX2VMNDZGNkJoRjg

However, you will notice that the end rows have very dramatic offset. In fact the pattern is directly related to the direction of travel of the machine. At the top of the map, all the swaths that are closest to the border are where the machine was traveling north and the swaths that are farther away from the border are the swaths where the machine was traveling south. This pattern makes sense as it is showing where the vehicle is when the application machine is running. Since the machine is 40 feet behind the tractor, going north, the tractor will be 40 farther north of the start/stop line and when going south, the tractor will be 40 feet farther south of the start/stop line. The following map showing the heading direction shows this very clearly.

http://drive.google.com/uc?export=view&id=0B3oZAe8v-JSxVmdKWHhqVHdrMEU

So the absolute GPS coordinates (X,Y, and Z) are correctly shown in this data set. The problem I have is with where the software plots the application data. When the system records the X, Y, and Z position, it is recording the rate that is being applied by the controller at that moment to that X, Y, and Z coordinate. Here is what the application data looks like in the raw form.

http://drive.google.com/uc?export=view&id=0B3oZAe8v-JSxTGVWN1lHb3V0ZG8

However, the actual position of that specific data should be stored at a point 40 feet behind the coordinate. Because of this, when I map the application data, the data going in opposite directions are offset by 80 feet and off 40 feet from where they really should be. I need to shift the location of the data by that 40 feet so the data is positioned properly and then map that result to create an accurate application map. I used Paint to shift the data points to where I'd like to see them here:

http://drive.google.com/uc?export=view&id=0B3oZAe8v-JSxSDcxSHlIRUozM1k

Keep in mind the original Z data should not shift, as that is absolutely related to the X and Y coordinate. However all the other data associated with that position needs to be shifted and given a new X, Y position based on the offset. I haven't been able to find a way to do this. Does anyone know how to do this? As I said, this should be a very common problem with data being imported as almost all data has some sort of delay (or the opposite if the implement is in front of the GPS). The import process should allow the user to assign a delay (positive or negative) based on time, distance, or both depending on the field operation.

Thanks for any help you can give me on this.



Edited 1 time(s). Last edit at 11/15/2016 11:24AM by JSteffen.
SubjectAuthorPosted

How do you adjust as applied map data for application offset from GPS

JSteffenNovember 11, 2016 06:13PM

Re: How do you adjust as applied map data for application offset from GPS

Deb HurrawNovember 14, 2016 10:10AM

Re: How do you adjust as applied map data for application offset from GPS

JSteffenNovember 14, 2016 11:23AM



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