No updates on this front, @bmaritz. Thanks for describing your usecase here. An external app may be your best bet. An alternative would be to have a form definition with a structure like this:
- a geotrace and instructions for the data collector to set it up to collect points automatically. They could lock the screen and still collect points. Then when they see a snake, they could save that trace and move on to the next question
- a block of questions about the snake encountered, possibly including a location question so you can easily map all snakes found without having to pull the last point of the trace
- instructions for the data collector to submit this encounter and start a new form submission
That way you could stitch together all of the traces collected to get the full coverage.
A similar alternative would be to put the structure I described above in a repeat. That way a data collector could fill out some information about the current survey and then capture all of their movement and snakes as part of that survey. Again, you could stitch together all the traces to get full coverage for that one survey.
Edit: the approaches I mentioned seem reasonable in this specific case because there aren't very many snakes encountered during a survey. They would not be practical for contexts in which there are many encounters.