Validation Criteria for Area Question

Hello,

I have a few questions on my form requesting users to click points on a map to outline an area. How can I require them to select exactly 10 (or any number) points on the map?

Thank you!

The number of points in a geoshape/geotrace can be determined by exploiting the fact that each coordinate component is separated by a space - much like the options in a select-multi list. Specifically:

numpoints = ((count-selected(${geoshape})-1) div 3)

You could then use this in a suitable constraint if you want to restrict it to a specific number of points.

[See https://forum.opendatakit.org/t/odk-geofence-v1/18656 for additional background if you are interested]

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Thank you!

Unfortunately, I am quite new to this. Would you be able to look at the picture below (I tried both options) and help with where I went wrong? I apologize if this is trivial.

I am quite new to form building so I apologize if this is trivial. I have a formula (numpoints = ((count-selected(${geoshape})-1) div 3)) to count the number of geopoints that the user has selected but am struggling to actually implement this. I have tried the following options but neither has worked (Iā€™m not even sure I am referring to the geopoints correctly).

In general, I am trying to require that a user select exactly ten points for the question so if there are better ways to implement this, please let me know!

Thank you!

Hi @kew96
I am just following up on this query which is quite interesting given the innovative way of using mapping data. Did you ever get a solution to this particular issue?

Stephane

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