Tractor Navigation Maps

Field Mapping Guidance Patterns: A Summary

When mapping fields or configuring automated guidance systems for precision agriculture, selecting the right directional pattern dictates your efficiency, soil compaction layout, and fuel consumption. Below is a breakdown of the two most common tracking methods.

1. Concentric Circles (Spiral Tracking)

The concentric circle pattern—often called “inside-out” or “outside-in” spiral tracking—follows the natural geometry of a field’s boundaries or the sweeping path of a center-pivot irrigation system.

• How it Works: The machine establishes an initial outer or inner boundary curve, and then replicates that exact curvature in continuous, concentric loops stepping inward or outward across the field.
• Best Used For:
  • Mapping and harvesting fields under center-pivot irrigation.
  • Irregularly shaped or circular field boundaries where straight lines would cause excessive short-rows.
• Pros:
  • Maximum Efficiency: Eliminates the need to stop, lift implements, and perform tight $180^\circ$ turns at the headlands.
  • Lower Fuel Consumption: Continuous motion keeps momentum steady, reducing machine wear and fuel burn.
• Cons:
  • Compaction Accumulation: Can concentrate soil compaction along the curving wheel tracks over time if paths are not deliberately offset.
  • Steering Adjustments: Requires constant, minor steering corrections (manually or via automated tracking) to maintain a flawless radius as the circle tightens.

2. Parallel Path A-B Lines (Straight Line Tracking)

Parallel A-B tracking is the bedrock foundation of precision farming and modern auto-steer systems, relying on two fixed coordinates to establish a grid.

• How it Works: The operator sets a starting point (Point A) and driving direction to a second point (Point B). The guidance software then projects a series of perfectly straight, parallel rows across the entire map based on the exact width of the implement.
• Best Used For:
  • Square, rectangular, or highly uniform block fields.
  • Row crop operations (e.g., corn, soybeans) requiring strict spacing for planters, sprayers, and combines.
• Pros:
  • Zero Overlap: Minimizes skips and overlaps down to the centimeter, drastically reducing input costs for seed, fertilizer, and chemical applications.
  • Ease of Use: Unmatched predictability; the operator can effortlessly skip rows to make wide, easy turns at the headlands.
• Cons:
  • Turning Inefficiency: Requires a significant amount of non-productive time and fuel spent turning the machine around at the ends of the field (headlands).
  • Pointless Inside Pivots: When applied blindly to a circular pivot field, it creates an excessive number of short, fragmented rows (“point rows”) that slow down field operations.

Pattern Summary Comparison

Agronomy Tip: Modern field mapping often uses a hybrid approach. For example, a grower might map 3 to 4 concentric “headland” loops around the outer edge of a field to create a comfortable turning buffer, and then switch to Parallel A-B lines to clean up the straight interior rows.

A. the initial cut into the center of the field

B. the five parallel ab lines, 1,4,3,5 that are used to combine a square section without turning hard left, in other word we cut line one shift over to the left skip line 2 and cut line 4, skip to line 3, skip to 2, then cut 5, resulting in a 50 meter by 50 meter plot where we can turn gradually into the spiral arc cutting inside out to the edge of the field, thus keeping the header full at all times, but note,

note: this is important, the grain cart problem, the grain cart can only get out by traversing that original cut into the center, is short order we have created a dust bowl. therefore C

C. alternate grain cart paths, and

D. cutting outside in. note another important note, cutting spiral paths outward will overheat the steering valve, so we change the spiral paths to concentric circles, the difference is the steering valve is open a little to one side, but stays at a constant opening. back to D, we can use a second machine or cut from outside in.

E. the ab lines for parallel initial 1,4,3,2,5 tracs, then cutting parallel swaths to harvest the triangular corners.

F. notice the irregular field needs a custom ab line to cut the tail.