Distance measurement is wrong

[fuliaoli]

Hi,

I'm using ESRI base maps and add local UTM layers in my map app. From I can read, UTM layers would be magically re-projected into ESRI's web mercator. All UTM layers shows ok, but when I use Draw tool to measure the distance between the two borders of a Township, Range and Section(1 mile) I get 1.4miles. Does the distance calculation use a different projection? 

Does anyone have some ideas to solve the problem?  Please help.

Thanks in advance,

li

[DanPatterson_Retired]

check the data frame and file coordinate systems from their properties... there are 1.6 km per mile so 1.4 isn't close

[fuliaoli]

Dan,

Thanks a lot for your quick reply. I checked some samples again and tried by setting geodesic=true, which solved the calculation problem.

Have a happy Thanksgiving!

Regards,

li