I guess I should have read you question better... there is no distance tolerance for the fires. However this is relatively easy to do. See the code below. I just did a run, but less than 200 house have at most a single fire within a distance of 5km. I am running a test with 25km to check the results.
Code:
- The search distance can be specified on line 61
- Since your data uses foot as linear unit and your search distance is metric, line 62 contains the conversion from feet to meter
- Line 102 checks to see if the distance is within the search distance
- minimum distance and oid of nearest fire is provided anyway.
- To make it faster you could make a selection (select by location) of the fires that are with the search distance and use that as input.
import arcpy
from datetime import datetime, date, timedelta
from dateutil.relativedelta import relativedelta
def main():
# input fc's
fc_house = r"D:\Xander\GeoNet\DistFireHouse\shp\housesaledata.shp"
fc_fire = r"D:\Xander\GeoNet\DistFireHouse\shp\firehistory_NAD_fips3002_feet.shp"
# input field
fld_date_sale = "ma_date_dt"
# output fields
fld_dist = "Dist2Fire"
fld_fire_oid = "FireOID"
# additional fields
fld_FireMinArea = "FireMinAr"
fld_FireMaxArea = "FireMaxAr"
fld_FireMeanArea = "FireMeanAr"
fld_FireCount = "FireCount"
# add fields
addField(fc_house, fld_dist, "DOUBLE")
addField(fc_house, fld_fire_oid, "LONG")
# add additional fields
addField(fc_house, fld_FireMinArea, "DOUBLE")
addField(fc_house, fld_FireMaxArea, "DOUBLE")
addField(fc_house, fld_FireMeanArea, "DOUBLE")
addField(fc_house, fld_FireCount, "LONG")
# loop through houses
cnt = 0
flds = ("SHAPE@", fld_date_sale, fld_dist, fld_fire_oid, fld_FireMinArea,
fld_FireMaxArea, fld_FireMeanArea, fld_FireCount)
with arcpy.da.UpdateCursor(fc_house, flds) as curs:
for row in curs:
cnt += 1
if cnt % 25 == 0:
print "Processing house: {0}".format(cnt)
pnt = row[0]
date_sale = row[1]
results = getNearestFireAndAreaStats(fc_fire, pnt, date_sale)
row[2] = results[0] # dist nearest
row[3] = results[1] # oid nearest
row[4] = results[2] # Min Area
row[5] = results[3] # Max Area
row[6] = results[4] # Mean Area
row[7] = results[5] # Count Fires
curs.updateRow(row)
def addField(fc, fldname, fldtype):
if len(arcpy.ListFields(fc, wild_card=fldname)) == 0:
arcpy.AddField_management(fc, fldname, fldtype)
def getNearestFireAndAreaStats(fc, pnt, date_sale):
# maximum distance for fire
search_dist = 5000.0 # meters
ft_to_m = 0.30480061 # conversion feet to meter
# input fields
fld_year = "FIRE_YEAR"
fld_month = "FIRE_MONTH"
fld_day = "FIRE_DAY"
fld_area = "SHAPE_AREA"
# defaults
min_dist = 999999
oid_fire = -1
min_area = 9999999999
max_area = 0
sum_area = 0
mean_area = 0
cnt_fires = 0
# results
res = []
flds = ("SHAPE@", "OID@", fld_year, fld_month, fld_day, fld_area)
with arcpy.da.SearchCursor(fc, flds) as curs:
for row in curs:
polygon = row[0]
oid = row[1]
year = int(row[2])
try:
month = int(row[3])
except:
month = 6
try:
day = int(row[4])
except:
day = 15
if chkDate(date_sale, year, month, day):
# these are the fires we are looking for
dist = pnt.distanceTo(polygon)
if dist < min_dist:
min_dist = dist
oid_fire = oid
if (dist * ft_to_m) < search_dist:
area = row[5]
if cnt_fires == 0:
min_area = area
max_area = area
sum_area = area
else:
if area < min_area: min_area = area
if area > max_area: max_area = area
sum_area += area
cnt_fires += 1
if cnt_fires > 0:
mean_area = sum_area / float(cnt_fires)
else:
min_area = 0
return [min_dist * ft_to_m, oid_fire, min_area, max_area, mean_area, cnt_fires]
def chkDate(date_sale, year_fire, month_fire, day_fire):
date_fire = datetime(year=year_fire, month=month_fire, day=day_fire)
date_2monthsbefore_sale = date_sale + relativedelta(months=-2)
year_sale = date_sale.year
test = (year_fire >= year_sale - 7) and (date_fire < date_2monthsbefore_sale)
return test
if __name__ == '__main__':
main()
