get_cadastre_building_floors.py

"""Calculate building floors from the Spanish Cadastre GIS files (SHP).

Once logged, data can be downloaded from https://www.sedecatastro.gob.es/
and the data specification is at 
http://www.catastro.minhap.gob.es/ayuda/manual_descriptivo_shapefile.pdf

This python script is to be used in the QGIS 2.x field calculator.
The "CONSTRU" field stores volumetric data and other attributes in the form 
of a structured text code. Floor numbers are in roman numerals.
As for example, "-II+IV+TZA" is a building part with two underground floors, 
four floors above ground and a roof terrace. This script analyzes the 
"CONSTRU" code to get an integer for the total floors.

This code is based on the Mark Pilgrim's script
Convert to and from Roman numerals (http://diveintopython.org/)

Copyright (C) 2016 Benito M. Zaragozí
Authors: Benito M. Zaragozí (https://github.com/benizar)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>."""

from qgis.core import *
from qgis.gui import *
import re

#Define digit mapping
romanNumeralMap = (('M',  1000),
					('CM', 900),
					('D',  500),
					('CD', 400),
					('C',  100),
					('XC', 90),
					('L',  50),
					('XL', 40),
					('X',  10),
					('IX', 9),
					('V',  5),
					('IV', 4),
					('I',  1))

#Cadastrial attributes with no height
building_attributes = re.compile( '(DARSENA|PTLAN|HORREO|TERRENY|CAMPING|GOLF|ZPAV|ZBE|PRESA|CONS|RUINA|ZD|VOL|FUT|YJD|JD|TRF|ESC|DEP|PRG|SUELO|SILO|ETQ|TEN|PI|ALT|SS|EPT|CO|MAR|PJE|SOP|POR|TZA|P|T|B)')


@qgsfunction(args="auto", group='Custom')
def get_cadastre_building_floors(s, feature, parent):
	result=0
	#Remove all negative floors between -/+ characters or - alone
	s=re.sub('-.+?\+', '', s)
	s=s.split('-', 1)[0]

	#Remove building attributes
	s=building_attributes.sub( '', s)

	#Split by + signs
	s=s.split('+', 1)

	#Loop on all strings. If it's a roman numeral, sum it
	for i in s:
		if isRoman(i):
			result=result+fromRoman(i)
	
	return result


#Define pattern to detect valid Roman numerals
romanNumeralPattern = re.compile("""
	^                   # beginning of string
	M{0,4}              # thousands - 0 to 4 M's
	(CM|CD|D?C{0,3})    # hundreds - 900 (CM), 400 (CD), 0-300 (0 to 3 C's),
                        #            or 500-800 (D, followed by 0 to 3 C's)
	(XC|XL|L?X{0,3})    # tens - 90 (XC), 40 (XL), 0-30 (0 to 3 X's),
                        #        or 50-80 (L, followed by 0 to 3 X's)
	(IX|IV|V?I{0,3})    # ones - 9 (IX), 4 (IV), 0-3 (0 to 3 I's),
                        #        or 5-8 (V, followed by 0 to 3 I's)
	$                   # end of string
	""" ,re.VERBOSE)

#Check if its a roman numeral
def isRoman(s):
	result=1
	if not s:
		result=0
	if not romanNumeralPattern.search(s):
		result=0
	return result

#Convert Roman numeral to integer
def fromRoman(s):
	result = 0
	index = 0
	for numeral, integer in romanNumeralMap:
		while s[index:index+len(numeral)] == numeral:
			result += integer
			index += len(numeral)
	return result