I am creating a TIN of flood elevations from a polyline feature class that has elevations along a stream network (i.e. cross sections) and and stream corridor polygon feature class to clip the TIN (i.e. clip polygon). I am using cross sections as "hard lines" and clip polygon as "hard clip". I have done this for projects many times. Most of the time, the resulting TIN is what I am expecting, but occasionally it has these mysterious gaps that I cannot figure out why they happen. The attached graphic show an example. Does anyone know what may be causing this? Ive already check that the cross sections all have elevations are single part features, and that boundary is single part features.
A couple interesting observations:
- When I create small TINS of just those areas the resulting TIN is fine (no gap)
- If I create the TIN with just the cross sections, and then use edit TIN to add the clip polygon, that usually solves all or most of the gaps - no idea why these would give different results
Thanks for any insight!