Source code for pygrass.raster.category

# -*- coding: utf-8 -*-
Created on Thu Jun 28 17:44:14 2012

@author: pietro
import ctypes
from operator import itemgetter

import grass.lib.raster as libraster
from grass.exceptions import ImplementationError

from grass.pygrass.errors import GrassError
from grass.pygrass.utils import decode
from grass.pygrass.raster.raster_type import TYPE as RTYPE

[docs]class Category(list): """ I would like to add the following functions: Getting the umber of cats: Rast_number_of_cats() <- Important for ith access Getting and setting the title: Rast_get_cats_title() Rast_set_cats_title() Do not use these functions for category access: Rast_get_cat() and the specialized types for CELL, FCELL and DCELL. Since these functions are working on hidden static buffer. Use the ith-get methods: Rast_get_ith_c_cat() Rast_get_ith_f_cat() Rast_get_ith_d_cat() This can be implemented using an iterator too. So that the category object provides the [] access operator to the categories, returning a tuple (label, min, max). Using this, the category object must be aware of its raster map type. Set categories using: Rast_set_c_cat() Rast_set_f_cat() Rast_set_d_cat() Misc: Rast_sort_cats() Rast_copy_cats() <- This should be wrapped so that categories from an existing Python category class are copied. """ def __init__(self, name, mapset='', mtype='CELL', *args, **kargs): = name self.mapset = mapset self.c_cats = libraster.Categories() libraster.Rast_init_cats("", ctypes.byref(self.c_cats)) self._mtype = mtype self._gtype = None if mtype is None else RTYPE[mtype]['grass type'] super(Category, self).__init__(*args, **kargs) def _get_mtype(self): return self._mtype def _set_mtype(self, mtype): if mtype.upper() not in ('CELL', 'FCELL', 'DCELL'): raise ValueError(_("Raster type: {0} not supported".format(mtype))) self._mtype = mtype self._gtype = RTYPE[self.mtype]['grass type'] mtype = property(fget=_get_mtype, fset=_set_mtype, doc="Set or obtain raster data type") def _get_title(self): return libraster.Rast_get_cats_title(ctypes.byref(self.c_cats)) def _set_title(self, newtitle): return libraster.Rast_set_cats_title(newtitle, ctypes.byref(self.c_cats)) title = property(fget=_get_title, fset=_set_title, doc="Set or obtain raster title") def __str__(self): return self.__repr__() def __list__(self): cats = [] for cat in self.__iter__(): cats.append(cat) return cats def __dict__(self): diz = dict() for cat in self.__iter__(): label, min_cat, max_cat = cat diz[(min_cat, max_cat)] = label return diz def __repr__(self): cats = [] for cat in self.__iter__(): cats.append(repr(cat)) return "[{0}]".format(',\n '.join(cats)) def _chk_index(self, index): if type(index) == str: try: index = self.labels().index(index) except ValueError: raise KeyError(index) return index def _chk_value(self, value): if type(value) == tuple: length = len(value) if length == 2: label, min_cat = value value = (label, min_cat, None) elif length < 2 or length > 3: raise TypeError('Tuple with a length that is not supported.') else: raise TypeError('Only Tuple are supported.') return value def __getitem__(self, index): return super(Category, self).__getitem__(self._chk_index(index)) def __setitem__(self, index, value): return super(Category, self).__setitem__(self._chk_index(index), self._chk_value(value)) def _get_c_cat(self, index): """Returns i-th description and i-th data range from the list of category descriptions with corresponding data ranges. end points of data interval. Rast_get_ith_cat(const struct Categories * pcats, int i, void * rast1, void * rast2, RASTER_MAP_TYPE data_type ) """ min_cat = ctypes.pointer(RTYPE[self.mtype]['grass def']()) max_cat = ctypes.pointer(RTYPE[self.mtype]['grass def']()) lab = decode(libraster.Rast_get_ith_cat(ctypes.byref(self.c_cats), index, ctypes.cast(min_cat, ctypes.c_void_p), ctypes.cast(max_cat, ctypes.c_void_p), self._gtype)) # Manage C function Errors if lab == '': raise GrassError(_("Error executing: Rast_get_ith_cat")) if max_cat.contents.value == min_cat.contents.value: max_cat = None else: max_cat = max_cat.contents.value return lab, min_cat.contents.value, max_cat def _set_c_cat(self, label, min_cat, max_cat=None): """Adds the label for range min through max in category structure cats. int Rast_set_cat(const void * rast1, const void * rast2, const char * label, struct Categories * pcats, RASTER_MAP_TYPE data_type ) """ max_cat = min_cat if max_cat is None else max_cat min_cat = ctypes.pointer(RTYPE[self.mtype]['grass def'](min_cat)) max_cat = ctypes.pointer(RTYPE[self.mtype]['grass def'](max_cat)) err = libraster.Rast_set_cat(ctypes.cast(min_cat, ctypes.c_void_p), ctypes.cast(max_cat, ctypes.c_void_p), label, ctypes.byref(self.c_cats), self._gtype) # Manage C function Errors if err == 1: return None elif err == 0: raise GrassError(_("Null value detected")) elif err == -1: raise GrassError(_("Error executing: Rast_set_cat")) def __del__(self): libraster.Rast_free_cats(ctypes.byref(self.c_cats))
[docs] def get_cat(self, index): return self.__getitem__(index)
[docs] def set_cat(self, index, value): if index is None: self.append(value) elif index < self.__len__(): self.__setitem__(index, value) else: raise TypeError("Index outside range.")
[docs] def reset(self): for i in range(len(self) - 1, -1, -1): del(self[i]) libraster.Rast_init_cats("", ctypes.byref(self.c_cats))
def _read_cats(self): """Copy from the C struct to the list""" for i in range(self.c_cats.ncats): self.append(self._get_c_cat(i)) def _write_cats(self): """Copy from the list data to the C struct""" # reset only the C struct libraster.Rast_init_cats("", ctypes.byref(self.c_cats)) # write to the c struct for cat in self.__iter__(): label, min_cat, max_cat = cat if max_cat is None: max_cat = min_cat self._set_c_cat(label, min_cat, max_cat)
[docs] def read(self): """Read categories from a raster map The category file for raster map name in mapset is read into the cats structure. If there is an error reading the category file, a diagnostic message is printed. int Rast_read_cats(const char * name, const char * mapset, struct Categories * pcats ) """ self.reset() err = libraster.Rast_read_cats(, self.mapset, ctypes.byref(self.c_cats)) if err == -1: raise GrassError("Can not read the categories.") # copy from C struct to list self._read_cats()
[docs] def write(self): """Writes the category file for the raster map name in the current mapset from the cats structure. void Rast_write_cats(const char * name, struct Categories * cats ) """ # copy from list to C struct self._write_cats() # write to the map libraster.Rast_write_cats(, ctypes.byref(self.c_cats))
[docs] def copy(self, category): """Copy from another Category class :param category: Category class to be copied :type category: Category object """ libraster.Rast_copy_cats(ctypes.byref(self.c_cats), # to ctypes.byref(category.c_cats)) # from self._read_cats()
[docs] def ncats(self): return self.__len__()
[docs] def set_cats_fmt(self, fmt, m1, a1, m2, a2): """Not implemented yet. void Rast_set_cats_fmt() """ # TODO: add raise ImplementationError("set_cats_fmt() is not implemented yet.")
[docs] def read_rules(self, filename, sep=':'): """Copy categories from a rules file, default separetor is ':', the columns must be: min and/or max and label. :: 1:forest 2:road 3:urban 0.:0.5:forest 0.5:1.0:road 1.0:1.5:urban :param str filename: the name of file with categories rules :param str sep: the separator used to divide values and category """ self.reset() with open(filename, 'r') as f: for row in f.readlines(): cat = row.strip().split(sep) if len(cat) == 2: label, min_cat = cat max_cat = None elif len(cat) == 3: label, min_cat, max_cat = cat else: raise TypeError("Row length is greater than 3") self.append((label, min_cat, max_cat))
[docs] def write_rules(self, filename, sep=':'): """Copy categories from a rules file, default separetor is ':', the columns must be: min and/or max and label. :: 1:forest 2:road 3:urban 0.:0.5:forest 0.5:1.0:road 1.0:1.5:urban :param str filename: the name of file with categories rules :param str sep: the separator used to divide values and category """ with open(filename, 'w') as f: cats = [] for cat in self.__iter__(): if cat[-1] is None: cat = cat[:-1] cats.append(sep.join([str(i) for i in cat])) f.write('\n'.join(cats))
[docs] def sort(self): libraster.Rast_sort_cats(ctypes.byref(self.c_cats))
[docs] def labels(self): return list(map(itemgetter(0), self))