# -*- coding: utf-8 -*-
# ---------------------------------------------------------------------------
# podil.py - vypocita aku plochu (absolutnu a relativnu - %) ma nejaka polygonova vrstva v administrativnych jednotkach
# ---------------------------------------------------------------------------

# Import arcpy module
import arcpy
from arcpy import env

# Script arguments, user dialog
in_features = arcpy.GetParameterAsText(0) # polygony ktorych rozsah chceme zistit
clip_features = arcpy.GetParameterAsText(1) # admin. jednotky
Output_Feature_Class = arcpy.GetParameterAsText(2)+"\clip.shp" # súbor pre dočasné uloženie orezov

# Set workspace 
env.workspace = clip_features

rows = arcpy.UpdateCursor(clip_features) # iterator pre admin. jednotky

# pridnie stlpcov do ktorych sa ulozi vysledok vypoctu
#arcpy.AddField_management(clip_features,"p_abs","FLOAT")
#arcpy.AddField_management(clip_features,"p_rel","FLOAT")

# zistenie plochy orezov
def total_area(infc):
	rws = arcpy.SearchCursor(infc) # iterator pre orezy
	area=0.
	for i in rws:  # objekt sa moze skladat z viacerych polygonov, preto zistujem celkovu plochu pomocou for cyklu
		polygon=i.SHAPE
		a = polygon.getArea()
		area = area + a
	return area

for row in rows:
	Feature = row.SHAPE #pristupujem ku geometrii jednotlivych jednotiek
	clip = arcpy.Clip_analysis(in_features, Feature, Output_Feature_Class, "") # orez
	tot_area = total_area(clip) # zistujem plochu orezu pomocou funkcie total_area (vid. vyssie)
	unit_area = Feature.getArea() # plocha admin. jednotky
	rel_area = (tot_area / unit_area)*100. # rel. plocha
	row.p_abs = float(tot_area) # zapis do atr. tabulky
	row.p_rel = float(rel_area)
	

arcpy.Delete_management(Output_Feature_Class) # mazem orezy