Distance varies after Copy parallel of road lines

[YuvarajuDhananjay]

Hi 

I am using copy parallel for either side of road lines for example of 80ft, but after measuring those lines it's showing 62.45ft it's more than 20ft of difference!!

Can anyone please help me on this?

 CP: copy parallel 

[LindaWilliams1]

Have you checked the distance using Planar mode instead of Geodesic in the Measure Distance Options?

[YuvarajuDhananjay]

In the Planer mode it's showing Correct distance, but we need it in Geodesic mode only

[Robert_LeClair]

My guess is your feature class that you're using to do a Copy Parallel is in a projected coordinate system and maybe projecting on the fly.  Hence the measurements being off.  To test this, I took an input line feature class that was in a UTM projection, reprojected it to WGS1984, did a Copy Parallel workflow of 80' and then measured using Geodesic Mode.  80' on both sides.  No issues.  What is your workflow?

[YuvarajuDhananjay]

we should use WGS 1984 web Mercator (auxiliary sphere) for all our work. using this coordinate system how to get the same distance as 80ft after copy parallel? 

[Robert_LeClair]

Yuvaraju - to mimic your described workflow, I reprojected my feature class to WGS 1984 Web Mercator using the Project GP tool.  Then added the newly projected feature class to a new map view in ArcGIS Pro. The coordinate system for the Map View is WGS 1984 Web Mercator so no project on the fly issues there.  I ran the Copy Parallel command, 80' on both sides and then used the measure tool.  80' on both sides using Geodesic/Imperial.  There is no option for Planar.  

[YuvarajuDhananjay]

Hi Robert, thanks for the reply, could you please describe what was Project GP tool, please explain how you have done it. 

[Robert_LeClair]

Hi Yuvaraju - so the Project GP tool takes a feature class in a projected coordinate system or geographic coordinate system and writes out a new feature class is another projected or geographic coordinate system.  For example, my input Feature Class is UTM Zone 13N, NAD83 and I want the output to be in WGS1984.  The Project GP tool would do that for me!

[YuvarajuDhananjay]

Robert, I used the Project GP tool to convert from one to another coordinate system, first, I did the change the coordinate system of the present map to UTM13N then I added a new line layer and did Copy parallel 40ft on both sides, and saved it. and opened a new map and did Define projection using the saved SHP file to the WGS1984 web Mercator and i measured those lines, which is giving 60ft instead of 80ft.