rescale_measures: Rescale Aggregate id Measure to id Measure
Description
Given an aggregate_id (e.g. reachcode in NHDPlus) measure and
the from and to measure for an id (e.g. COMID flowline in NHDPlus), returns
the measure along the id flowline. This is useful where many flowlines make
up a single aggregate feature. "Measures" are typically referenced to the
aggregate feature. Flowlines have a stated from-measure / to-measure. In
some cases it is useful to rescale the measure such that it is relative only
to the flowline.
from is downstream -- 0 is the outlet
to is upstream -- 100 is the inlet