Hi Phil,
Although the question might seem easy, there is no standard tool in ArcGIS to create this type of output. The Solar Radiation tools in ArcGIS can evaluated the polygon derived in your analysis: ArcGIS Help (10.2, 10.2.1, and 10.2.2)
For questions like yours, a python script might be an option. I created a start for you based on a script "sunpos.py" downloaded from:
https://raw.githubusercontent.com/minopret/sunpos/master/sunpos.py
The idea is to iterate over a date interval. During the iteration there is a second loop over a time interval. I would suggest that you avoid getting near to sunrise and sunset since this would create an angle so small that you would have to clear a lot of forest. Based on the location provided (lat, lon values in script) the altitude and azimuth are returned for each date, time. To make this data manageable, I rounded azimuth to a whole number and create a dictionary to hold the minimum altitude values of the sun. At the end the dictionary is sorted and can be used (not yet implemented) to translate to distance of clearing forest. The azimuth and distance should be translated to a geographic location and can be combined to create a polygon for logging.
import sunpos
# downloaded from: https://raw.githubusercontent.com/minopret/sunpos/master/sunpos.py
import collections
from datetime import date, timedelta
# setting
start_date = date(2014, 5, 15)
end_date = date(2014, 9, 30)
start_time = 9 # 9 am
end_time = 17 # 5 pm
time_interval = 1 # 0.25 = every 15 minutes
lat = 4.5
lon = -74
dct = {}
d = start_date
delta = timedelta(days=1)
while d <= end_date:
t = start_time
while t <= end_time:
alt, azi = sunpos.time_and_location_to_sun_alt_azimuth(d.year, d.month, d.day, t, lat, lon)
azi2 = round(azi)
if azi2 in dct:
if alt < dct[azi2]:
dct[azi2] = alt
else:
dct[azi2] = alt
# update dictionary (rounded azimuth vs min altitud)
t += time_interval
d += delta
odct = collections.OrderedDict(sorted(dct.items()))
# now you have a list of angles that you could translate to a distance
print "azimuth\taltitud"
for azi, alt in odct.items():
print "{0}\t{1}".format(azi, alt if alt <= 90 else 360 - alt)
Hope this helps you a bit.
Kind regards, Xander
