app freezes when polygon is too small

Hi Map Pilot team,

My app (Map Pilot for Business v4.1.5) froze several times while in the field planning a mission and I wasn't able to rescue the field operation, but I was able to isolate and recreate the problem once I was back home. I think this is a place where an informative error message could be useful.

In short, if I plan a mission with a very small polygon and the flight paths, based on current altitude and side overlap settings, would be spaced further apart than the width of that polygon, the app freezes.

To reproduce the freeze: set altitude to 300m, set side overlap to 70%. Tap once-twice-thrice to build a small triangular survey area about 50m on the non-hypotenuse sides. Drag the midpoint of the hypotenuse out to form a small square. Double tap to estimate the takeoff point and the app freezes.

This situation came about because I was using silly parameters (60% side overlap; 300m altitude) to plan a massive mission (hundreds of hectares) in the general vicinity of where I knew I wanted to fly so I could cache the background imagery and terrain tiles since I knew there'd be no cell service. Then in the field, those side overlap and altitude parameters were left over, so planning a small mission led to the app freezing instead of an error message of some kind and an opportunity to recover.

Of course, now I know to add this (set flight settings to something more reasonable before delineating the polygon) to the troubleshooting toolkit, but it might be nice for future Map Pilot versions to have a check for this sort of circumstance.

Thanks for the great app! It's still the only one I recommend to my various science colleagues for mapping vegetation in variable terrain.