Problem: Unable to draw parallel lines in a geographic coordinate system in ArcGIS Pro
In ArcGIS Pro, when drawing a parallel line using the Parallel function on a dataset in a geographic coordinate system (GCS), the line drawn is not parallel to the original line. Instead, the line is drawn at a certain angle as shown in the image below.
This is expected behaviour. The parallel function does not work with a Geographic Coordinate System. This is because the parallel lines are drawn onto a 3D surface in a GCS which follows the curvature of the earth.
Solution or Workaround
To resolve this issue, use a projected coordinate system (PCS) for both the dataset and the map view where the map is projected onto a flat surface. To do so, use the Project tool. Refer to ArcGIS Pro: Project for more information.The image below shows the parallel line created when using a projected coordinate system.
Note: If the lines are drawn in 3D scene, which by default is in a GCS, the line becomes curved as it respects the curvature of the earth.
- ArcGIS Pro: Constrain a segment parallel
- ArcGIS Pro: Configure a scene for 3D editing
- ArcGIS Pro: Coordinate systems, projections, and transformations