topic Re: Distance value of geotrace in ArcGIS Survey123 Questions

Distance value of geotrace

JamesCrandall — Thu, 23 May 2019 19:58:00 GMT

We're trying to convert the geotrace distance value into miles and not getting the correct result. That is, when comparing our conversion to miles it's wildly different from a known segment.

We thought it was a simple meters-to-miles conversion:

round((distance(${geotraceField}) div 1609.344), 2)

But this gives different result from a known line segment distance we're drawing in Survey.

Running a simple calculation on a note field:

(distance(${geoTraceField}) div 1609.344)

Value reported: 3.00

That same length using the measure tool in an AGOL webmap:

Value reported: 1.50 miles

Simple straight distance value:

distance(${geoTraceField})

Value reported: 4880

Re: Distance value of geotrace

JamesCrandall — Fri, 24 May 2019 12:59:51 GMT

I'm not sure why this is, but dividing the converted value from meters into miles by 2 seems to closely match the values generated in an AGOL mapviewer using the distance measure tool.

Would love to know reasons and/or if this is incorrect!

(distance(${geoTraceField}) div 1609.344) div 2

Re: Distance value of geotrace

JamesTedrick — Fri, 24 May 2019 16:59:04 GMT

Hi James,

Thanks for finding this! As you are probably aware, geotrace is still in-beta functionality, including associated functions like distance. I can replicate what you are seeing and will file an issue to correct this before geotrace is released.

Re: Distance value of geotrace

JamesCrandall — Fri, 24 May 2019 18:29:09 GMT

Thank you!

BTW, I'm fine with having to add an additional divisor!

Re: Distance value of geotrace

JamesTedrick — Tue, 28 May 2019 16:41:29 GMT

Hi James,

Just so you are aware, the issue is more complicated than being simply twice the expected value- the issue is that the distance function is treating the line as if it were a polygon and adding in a final segment from the last coordinate to the first coordinate. In a straight line case (such as a 2-point line), this will be double; other cases may see varying amounts of additional distance recorded (for example, you should see essentially no difference if you recorded a closed object such as a square).