Ensure that surveyors are within a certain radius of a given point

[ahblake]

I started typing up how to construct a geotrace string from your reference point and collected point and use the distance function to calculate what you need while thinking 'I bet @Xiphware has a better solution' and did a quick search...it's the same solution, but saves me the trouble of recreating it

Calculate distance between geopoints

Hi all, I am using ODK Collect (1.21.2) and XLS form, and I am designing a form to record locations for field collected insect samples. I'd like each new sampling location (in the same form) to be over a minimum distance from the one before it. Is it possible in the form to 1.Calculate the linear distance between sample geopoints, and 2. Have a constraint based on this minimum distance for new geopoints? Any advice/assistance would be greatly appreciated...

There's an example form in that thread, you would just need to replace one of the points with your reference location as a string in the concat/variable in the concat, then check that the output is <7000m

Here's the docs on the distance function:

Form Operators and Functions