[Talk-us] note to folks doing mapping based on aerial imagery

[Richard Welty]

please don't go overboard mapping areas from imagery where you
can't do ground surveys, particularly where there are clearly local mappers
working. if there is significant variance from the imagery, and there is
clearly a local mapper working there (check the history, folks, please)
then contact the local before doing anything major.

this is the second time i've had to repair the area in Troy, NY
in the vicinity of 6th Avenue to 8th Street, along Congress and
Ferry. the roads have been reconstructed and realigned since
the most recent aerial photography, and twice now my work
has been "fixed" by well meaning out-of-area mappers working
from imagery.

richard