Arcgis Pro backsight angle

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05-06-2020 06:41 AM
AaronWorthley1
Occasional Contributor II

Is it possible to draw a line segment by entering a backsight angle as with the angle-distance COGO course in ArcMap?

I need to draw a line with the second segment at a backsight angle to the first segment-ie. a straight line would be 180 degrees. This is easy using COGO tools in ArcMap, but I can't find any similar option in Pro...

see: About creating a line with the Traverse window—Help | Documentation Angle-Distance Course.

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3 Replies
KoryKramer
Esri Community Moderator

Maybe somebody in the ArcGIS Parcel Fabric‌ space can answer...

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jcarlson
MVP Esteemed Contributor

While I do wish there were a more direct way of entering these sorts of angles, this is possible using the Segment Deflection tool, found in the context menu during a sketch operation. Because a traverse creates individual two-point line features, the standard Deflection tool is unavailable.

When you reach a call in your legal which has a backsight angle, simply right-click the previous line.

context menu during sketch operation

The following dialog will prompt you for the value of the deflection. Positive values for clockwise deflection, negative for counter-clockwise. Once entered, your sketch will now be constrained to the entered deflection value. Note that this can be used for a deflection "looking back" or "looking forward", so make sure you have your cursor in the appropriate direction before continuing. For this reason, always define the deflection prior to the distance, to ensure that your segment is created as intended.

deflection direction a+45 degree deflection from the previous call.

deflection direction b

+45 degree deflection from the prolongation of the previous call.

Once your deflection is defined, right-click and select distance, or press D on your keyboard to enter the distance of the call. Once the direction and distance are both constrained, the feature will be automatically created. As with all manually digitized calls in the Traverse tool, this new feature will have generated dimensions, meaning that the COGO values will not be stored in the feature attributes, if applicable. See the Create a Traverse Pro documentation for more on that.

generated dimensions

Hopefully this helps you deal with those pesky backsight angles.

- Josh Carlson
Kendall County GIS
AaronWorthley1
Occasional Contributor II

Thanks Josh, very helpful!

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