How to create circular passes

Use the "Max Headlands" option for encircled non-traversable holes to create circular passes.

Overview

For Steward operators that are working fields with circular irrigation pivots, creating a coverage plan with circular passes can often be more efficient. This guide explains how to utilize the "Max Headlands" option to generate circular passes in a coverage plan that are concentric to the irrigation pivot’s center.

Measure your irrigation pivot

Before we can create an accurate representation of the circular irrigation pivot in vMC, we must measure the physical irrigation pivot in the field.

Steps to measure the circular irrigation pivot

1. Identify the geographic coordinates of the center of the irrigation pivot.
2. Measure the distance from the center of the pivot to the edge of the area where it is safe to work the field. When measuring the distance between the center and the edge of the field, you must ensure that the distance overlaps with the field boundary you have defined in vMC. Additionally, you will want to make sure that this distance is greater than or equal to the minimum turn radius of your vehicle and implement. 

Adding pivot center geometry

In order to begin using the “Max Headlands” option to create circular passes, a circular shape representing the center of the irrigation pivot must be added to the field you are working within. 

Steps to adding circular geometry

1. Export your field boundary from vMC by clicking on the geometry and pressing “Export Geometry”
2. Navigate to geojson.io and open the exported field boundary file.
3. Drop a pin on the map and update the coordinates of that pin to the coordinates of the center of the pivot that you identified earlier.
4. Zoom in to the pin as close as possible and use the circle drawing tool within geojson.io to create a circle that’s center is as close as possible to the base of the pin, representing the center of your circular irrigation pivot. Extend the radius of the circle to the distance you measured to overlap with the edge of your field boundary.
5. Once you are satisfied with the circular geometry that represents the center of the irrigation pivot, save this geometry from geojson.io as a .kml file.

Configuring the coverage plan

Now, it’s time to use the circular geometry that you created and generate a coverage plan with circular passes that are concentric to this geometry.

Steps to creating circular passes

1. Import only the circular geometry into your field as a non-traversable hole and name it “Pivot Center” or something similar so that you can more easily recognize it when creating your coverage plans. Make sure not to import your field boundary as well so that there are not duplicate overlapping field boundaries.
2. While viewing the field, create a new template by selecting the “Templates” button and then “New Template”.
3. When configuring the field boundary’s geometry, we recommend setting the type to “encircled” and having 4+ headlands to give the vehicle enough room to turn around. Increasing the number of headlands beyond the recommended amount will also help to reduce the amount of potential geofence violations and the need to add a geofence offset when generating missions on this coverage plan. 
4. Configure your coverage plan template as usual. 
5. When configuring the “Pivot Center” non-traversable hole, change the headland type to “Encircled” and then select “Max Headlands” for the number of headlands.
6. Press “Generate” to generate the coverage plan.
7. Press “Save” to save the coverage plan as a template.

Troubleshooting

During this process, you may encounter a few different challenges:

Working around pivot track ruts

If you have deep ruts in the field due to the pivot tracks that you would like to avoid, you can mark the passes that overlap those ruts as “complete” while viewing the coverage plan.

Geofence violations

If you find that missions generated from this coverage plan result in geofence violations, it may be that there is not enough room to perform a turn within the geofence. To circumvent this, we recommend creating a new coverage plan and increasing the number of boundary headlands.

Too many cross-field traversals

If you find that missions generate a large number of cross-field traversals, we recommend entering the traversal_type: along_boundary advanced parameter and generating the mission again. Using this parameter should dramatically reduce the number of cross-field traversals, if not eliminate them entirely.

Transits cross through non-traversable holes

If you find that missions generate transits through non-traversable holes, we recommend breaking up the field divided by non-traversable holes into multiple smaller field boundaries.