plant_height integration code

[max-zilla]

@ZongyangLi I just merged a pull request that, among other things, added a function for plant_height extractor to use my "rulechecker" extractor to only trigger extractor when we have a whole day of PLY files available.

https://github.com/terraref/extractors-3dscanner/blob/master/plant_height/rules.py#L67

This means that when plant_height extractor triggers now, it will be given a list of all the _west.PLY files for a given day. We can replace 'west' with 'east' in those filenames to get east files as well.

Can you post or share your integration code that triggers on a directory or list of PLY files that I can call to generate plot-level data from this list? Then we can try to combine them.

[ZongyangLi]

@max-zilla
The following function is the integration code for height distribution.
https://github.com/terraref/extractors-3dscanner/blob/master/plant_height/full_day_to_histogram.py#L298

in_dir is a super_dir, so I guess dirsare the same as the list file you are providing. As @rmgarnett 's request, plots are divided into 1728 plots, so each scan have a totally 32 plots, rather than 16 plots.