osrm_utils.py

# -*- coding: utf-8 -*-
"""
osrm_utils
----------
Utilities function used for the plugin.

"""
import numpy as np
from itertools import islice
from PyQt4.QtGui import QColor, QFileDialog, QDialog, QMessageBox, QProgressBar
from PyQt4.QtCore import QSettings, QFileInfo, Qt
from qgis.core import (
    QgsGeometry, QgsPoint, QgsCoordinateReferenceSystem, QgsProject,
    QgsCoordinateTransform, QgsSymbolV2, QgsMessageLog
    )
from qgis.gui import QgsEncodingFileDialog
from matplotlib.pyplot import contourf
from matplotlib.mlab import griddata
import urllib2
from .osrm_utils_extern import PolylineCodec, lru_cache
import json

__all__ = ['check_host', 'save_dialog', 'save_dialog_geo', 'prep_access',
           'qgsgeom_from_mpl_collec', 'prepare_route_symbol',
           'encode_to_polyline', 'interpolate_from_times', 'get_coords_ids',
           'chunk_it', 'pts_ref', 'TemplateOsrm', "put_on_top",
           "check_profile_name", 'decode_geom', 'fetch_table',
           'decode_geom_to_pts', 'fetch_nearest',
           'make_regular_points', 'get_search_frame', 'get_isochrones_colors']


def _chain(*lists):
    for li in lists:
        for elem in li:
            yield elem


def encode_to_polyline(pts):
    output = []

    def write_enc(coord):
        coord = int(round(coord * 1e5))
        coord <<= 1
        coord = coord if coord >= 0 else ~coord
        while coord >= 0x20:
            output.append((0x20 | (coord & 0x1f)) + 63)
            coord >>= 5
        output.append(coord + 63)

    write_enc(pts[0][0])
    write_enc(pts[0][1])
    for i, pt in enumerate(pts[1:]):
        write_enc(pt[0] - pts[i][0])
        write_enc(pt[1] - pts[i][1])
    return ''.join([chr(i) for i in output])


def prep_access(time_param):
    """Make the regular grid of points, snap them and compute tables"""
    point = time_param['point']
    max_time = time_param['max']
    levels = time_param["levels"]

    url = ''.join(["http://", time_param["host"], '/table/', time_param["profile"], '/'])
    bounds = get_search_frame(point, max_time)
    coords_grid = make_regular_points(bounds, time_param["max_points"])

    times, origin_pt, snapped_dest_coords = \
        fetch_table(url, [point], coords_grid)

    times = (times[0] / 60.0).round(2)  # Round values in minutes

    # Fetch MatPlotLib polygons from a griddata interpolation
    collec_poly = interpolate_from_times(
        times, np.array(snapped_dest_coords), levels)

    # Convert MatPlotLib polygons to QgsGeometry polygons :
    polygons = qgsgeom_from_mpl_collec(collec_poly.collections)

    return polygons


class TemplateOsrm(object):
    """
    Template class to be subclassed by each OSRM dialog class.
    It contains some methods used by the five next class.
    """
    def display_error(self, error, code):
        msg = {
            1: "An error occured when trying to contact the OSRM instance",
            2: "OSRM plugin error report : Too many errors occured "
               "when trying to contact the OSRM instance at {} - "
               "Route calculation has been stopped".format(self.host),
            }
        self.iface.messageBar().clearWidgets()
        self.iface.messageBar().pushMessage(
            "Error", msg[code] + "(see QGis log for error traceback)",
            duration=10)
        QgsMessageLog.logMessage(
            'OSRM-plugin error report :\n {}'.format(error),
            level=QgsMessageLog.WARNING)

    def make_prog_bar(self):
        progMessageBar = self.iface.messageBar().createMessage(
            "Creation in progress...")
        self.progress = QProgressBar()
        self.progress.setMaximum(10)
        self.progress.setAlignment(Qt.AlignLeft | Qt.AlignVCenter)
        progMessageBar.layout().addWidget(self.progress)
        self.iface.messageBar().pushWidget(
            progMessageBar, self.iface.messageBar().INFO)

    @staticmethod
    @lru_cache(maxsize=30)
    def query_url(url):
        r = urllib2.urlopen(url)
        return json.loads(r.read(), strict=False)

    def print_about(self):
        mbox = QMessageBox(self.iface.mainWindow())
        mbox.setIcon(QMessageBox.Information)
        mbox.setWindowTitle('About')
        mbox.setTextFormat(Qt.RichText)
        mbox.setText(
            "<p><b>(Unofficial) OSRM plugin for qgis</b><br><br>"
            "Author: mthh, 2015<br>Licence : GNU GPL v2<br><br><br>Underlying "
            "routing engine is <a href='http://project-osrm.org'>OSRM</a>"
            "(Open Source Routing Engine) :<br>- Based on <a href='http://"
            "www.openstreetmap.org/copyright'>OpenStreetMap</a> "
            "dataset<br>- Easy to start a local instance<br>"
            "- Pretty fast engine (based on contraction hierarchies and mainly"
            " writen in C++)<br>- Mainly authored by D. Luxen and C. "
            "Vetter<br>(<a href='http://project-osrm.org'>http://project-osrm"
            ".org</a> or <a href='https://github.com/Project-OSRM/osrm"
            "-backend#references-in-publications'>on GitHub</a>)<br></p>")
        mbox.open()

    def store_origin(self, point):
        """
        Method to store a click on the QGIS canvas
        """
        if '4326' not in self.canvas.mapSettings().destinationCrs().authid():
            crsSrc = self.canvas.mapSettings().destinationCrs()
            xform = QgsCoordinateTransform(
                crsSrc, QgsCoordinateReferenceSystem(4326))
            point = xform.transform(point)
        self.origin = point
        self.canvas.unsetMapTool(self.originEmit)
        self.lineEdit_xyO.setText(str(point))


def check_profile_name(profile_name):
    assert len(profile_name) > 3
    assert "/" in profile_name
    return profile_name


@lru_cache(maxsize=30)
def check_host(url):
    """
    Helper function to get the hostname in desired format
    (i.e without "http://", with the port if needed
        and without the last '/')
    """
    if len(url) < 4:
        raise ValueError('Probably empty/non-valable url')
    if not ('http' in url and '//' in url) and url[-1] == '/':
        host = url[:-1]
    elif not ('http:' in url and '//' in url):
        host = url
    elif 'http://' in url[:7] and url[-1] == '/':
        host = url[7:-1]
    elif 'http://' in url[:7]:
        host = url[7:]
    else:
        host = url
    return host


def save_dialog(filtering="CSV (*.csv *.CSV)"):
    settings = QSettings()
    dirName = settings.value("/UI/lastShapefileDir")
    encode = settings.value("/UI/encoding")
    fileDialog = QgsEncodingFileDialog(
        None, "Save output csv", dirName, filtering, encode
        )
    fileDialog.setDefaultSuffix('csv')
    fileDialog.setFileMode(QFileDialog.AnyFile)
    fileDialog.setAcceptMode(QFileDialog.AcceptSave)
    fileDialog.setConfirmOverwrite(True)
    if not fileDialog.exec_() == QDialog.Accepted:
        return None, None
    files = fileDialog.selectedFiles()
    settings.setValue("/UI/lastShapefileDir",
                      QFileInfo(unicode(files[0])).absolutePath())
    return (unicode(files[0]), unicode(fileDialog.encoding()))


def save_dialog_geo(filtering="ESRI Shapefile (*.shp *.SHP)"):
    settings = QSettings()
    dirName = settings.value("/UI/lastShapefileDir")
    encode = settings.value("/UI/encoding")
    fileDialog = QgsEncodingFileDialog(
        None, "Save output ShapeFile", dirName, filtering, encode
        )
    fileDialog.setDefaultSuffix('shp')
    fileDialog.setFileMode(QFileDialog.AnyFile)
    fileDialog.setAcceptMode(QFileDialog.AcceptSave)
    fileDialog.setConfirmOverwrite(True)
    if not fileDialog.exec_() == QDialog.Accepted:
        return None, None
    files = fileDialog.selectedFiles()
    settings.setValue("/UI/lastShapefileDir",
                      QFileInfo(unicode(files[0])).absolutePath())
    return (unicode(files[0]), unicode(fileDialog.encoding()))


def prepare_route_symbol(nb_route):
    colors = ['#1f78b4', '#ffff01', '#ff7f00',
              '#fb9a99', '#b2df8a', '#e31a1c']
    p = nb_route % len(colors)
    my_symb = QgsSymbolV2.defaultSymbol(1)
    my_symb.setColor(QColor(colors[p]))
    my_symb.setWidth(1.2)
    return my_symb


def qgsgeom_from_mpl_collec(collections):
    polygons = []
    for i, polygon in enumerate(collections):
        mpoly = []
        for path in polygon.get_paths():
            path.should_simplify = False
            poly = path.to_polygons()
            if len(poly) > 0 and len(poly[0]) > 3:
                exterior = [QgsPoint(*p.tolist()) for p in poly[0]]
                holes = [[QgsPoint(*p.tolist()) for p in h]
                         for h in poly[1:] if len(h) > 3]
                if len(holes) == 1:
                    mpoly.append([exterior, holes[0]])
                elif len(holes) > 1:
                    mpoly.append([exterior] + [h for h in holes])
                else:
                    mpoly.append([exterior])

        if len(mpoly) == 1:
            polygons.append(QgsGeometry.fromPolygon(mpoly[0]))
        elif len(mpoly) > 1:
            polygons.append(QgsGeometry.fromMultiPolygon(mpoly))
        else:
            polygons.append(QgsGeometry.fromPolygon([]))
    return polygons


def interpolate_from_times(times, coords, levels, rev_coords=False):
    if not rev_coords:
        x = coords[..., 0]
        y = coords[..., 1]
    else:
        x = coords[..., 1]
        y = coords[..., 0]
    xi = np.linspace(np.nanmin(x), np.nanmax(x), 200)
    yi = np.linspace(np.nanmin(y), np.nanmax(y), 200)
    zi = griddata(x, y, times, xi, yi, interp='linear')
    v_bnd = np.nanmax(abs(zi))
    collec_poly = contourf(
        xi, yi, zi, levels, vmax=v_bnd, vmin=-v_bnd)
    return collec_poly


def get_coords_ids(layer, field, on_selected=False):
    if on_selected:
        get_features_method = layer.selectedFeatures
    else:
        get_features_method = layer.getFeatures

    if '4326' not in layer.crs().authid():
        xform = QgsCoordinateTransform(
            layer.crs(), QgsCoordinateReferenceSystem(4326))
        coords = [xform.transform(ft.geometry().asPoint())
                  for ft in get_features_method()]
    else:
        coords = [ft.geometry().asPoint() for ft in get_features_method()]

    if field != '':
        ids = [ft.attribute(field) for ft in get_features_method()]
    else:
        ids = [ft.id() for ft in get_features_method()]

    return coords, ids


def chunk_it(it, size):
    it = iter(it)
    return list(iter(lambda: tuple(islice(it, size)), ()))


def pts_ref(features):
    return [i[3] for i in features]


def put_on_top(id_new_layer_top, id_old_layer_top):
    root = QgsProject.instance().layerTreeRoot()

    myblayer = root.findLayer(id_new_layer_top)
    myClone = myblayer.clone()
    parent = myblayer.parent()
    parent.insertChildNode(0, myClone)
    parent.removeChildNode(myblayer)

    myalayer = root.findLayer(id_old_layer_top)
    myClone = myalayer.clone()
    parent = myalayer.parent()
    parent.insertChildNode(1, myClone)
    parent.removeChildNode(myalayer)


def decode_geom(encoded_polyline):
    """
    Function decoding an encoded polyline (with 'encoded polyline
    algorithme') and returning a QgsGeometry object

    Params:

    encoded_polyline: str
        The encoded string to decode
    """
    return QgsGeometry.fromPolyline(
        [QgsPoint(i[1], i[0]) for i
         in PolylineCodec().decode(encoded_polyline)])


def fetch_table(url, coords_src, coords_dest):
    """
    Function wrapping OSRM 'table' function in order to get a matrix of
    time distance as a numpy array

    Params :
        - url, str: the start of the url to use
            (containing the host and the profile version/name)

        - coords_src, list: a python list of (x, y) coordinates to use
            (they will be used a "sources" if destinations coordinates are
             provided, otherwise they will be used as source and destination
             in order to build a "square"/"symetrical" matrix)

        - coords_dest, list or None: a python list of (x, y) coordinates to use
            (if set to None, only the sources coordinates will be used in order
            to build a "square"/"symetrical" matrix)

    Output:
        - a numpy array containing the time in tenth of seconds
            (where 2147483647 means not-found route)

        - a list of "snapped" source coordinates

        - a list of "snapped" destination coordinates
            (or None if no destination coordinates where provided)
    """
    if not coords_dest:
        query = ''.join(
            [url, "polyline(",
             encode_to_polyline([(c[1], c[0]) for c in coords_src]), ")"])
#            ';'.join([','.join([str(coord[0]), str(coord[1])]) for coord in coords_src])])
    else:
        src_end = len(coords_src)
        dest_end = src_end + len(coords_dest)
        query = ''.join([
            url,
            "polyline(",
            encode_to_polyline([(c[1], c[0]) for c in _chain(coords_src, coords_dest)]),
            ")",
#            ';'.join([','.join([str(coord[0]), str(coord[1])]) for coord in _chain(coords_src, coords_dest)]),
            '?sources=',
            ';'.join([str(i) for i in range(src_end)]),
            '&destinations=',
            ';'.join([str(j) for j in range(src_end, dest_end)])
            ])

    try:
        res = urllib2.urlopen(query)
        parsed_json = json.loads(res.read(), strict=False)
        assert parsed_json["code"] == "Ok"
        assert "durations" in parsed_json

    except AssertionError as er:
        raise ValueError('Error while contacting OSRM instance : \n{}'
                                  .format(er))
    except Exception as err:
        raise ValueError('Error while contacting OSRM instance : \n{}'
                                  .format(err))

    durations = np.array(parsed_json["durations"], dtype=float)
    new_src_coords = [ft["location"] for ft in parsed_json["sources"]]
    new_dest_coords = None if not coords_dest \
        else [ft["location"] for ft in parsed_json["destinations"]]

    return durations, new_src_coords, new_dest_coords


def decode_geom_to_pts(encoded_polyline):
    """
    Params:

    encoded_polyline: str
        The encoded string to decode
    """
    return [(i[1], i[0]) for i in PolylineCodec().decode(encoded_polyline)]


@lru_cache(maxsize=25)
def fetch_nearest(host, profile, coord):
    """
    Useless function wrapping OSRM 'locate' function,
    returning the reponse in JSON.
    More useless since newer version of OSRM doesn't include 'locate' function
    anymore.

    Parameters
    ----------
    coord: list/tuple of two floats
        (x ,y) where x is longitude and y is latitude
    host: str, like 'localhost:5000'
        Url and port of the OSRM instance (no final bakslash)

    Return
    ------
       The coordinates returned by OSRM (or False if any error is encountered)
    """
    url = ''.join(['http://', host, '/nearest/',
                   profile, '/', str(coord[0]), ',', str(coord[1])])
    try:  # Querying the OSRM instance
        rep = urllib2.urlopen(url)
        parsed_json = json.loads(rep.read(), strict=False)
    except Exception as err:
        print(err)
        return False
    if 'code' not in parsed_json or "Ok" not in parsed_json['code']:
        return False
    else:
        return parsed_json["waypoints"][0]["location"]


def make_regular_points(bounds, nb_pts):
    """
    Return a square grid of regular points (same number in height and width
    even if the bbox is not a square).
    """
    xmin, ymin, xmax, ymax = bounds
    nb_h = int(round(np.sqrt(nb_pts)))
    prog_x = [xmin + i * ((xmax - xmin) / nb_h) for i in range(nb_h + 1)]
    prog_y = [ymin + i * ((ymax - ymin) / nb_h) for i in range(nb_h + 1)]
    result = []
    for x in prog_x:
        for y in prog_y:
            result.append((x, y))
    return result


def get_search_frame(point, max_time):
    """
    Define the search frame (ie. the bbox), given a center point and
    the maximum time requested

    Return
    ------
    xmin, ymin, xmax, ymax : float
    """
    search_len = (max_time * 4) * 1000
    crsSrc = QgsCoordinateReferenceSystem(4326)
    xform = QgsCoordinateTransform(crsSrc, QgsCoordinateReferenceSystem(3857))
    point = xform.transform(QgsPoint(*point))
    xmin = point[0] - search_len
    ymin = point[1] - search_len
    xmax = point[0] + search_len
    ymax = point[1] + search_len
    crsSrc = QgsCoordinateReferenceSystem(3857)
    xform = QgsCoordinateTransform(crsSrc, QgsCoordinateReferenceSystem(4326))
    xmin, ymin = xform.transform(QgsPoint(xmin, ymin))
    xmax, ymax = xform.transform(QgsPoint(xmax, ymax))
    return xmin, ymin, xmax, ymax


def get_isochrones_colors(nb_features):
    """ Ugly "helper" function to rewrite to avoid repetitions """
    return {1: ('#a6d96a',),
            2: ('#fee08b', '#a6d96a'),
            3: ('#66bd63',
                '#fee08b', '#f46d43'),
            4: ('#1a9850', '#a6d96a',
                '#fee08b', '#f46d43'),
            5: ('#1a9850', '#66bd63',
                '#ffffbf', '#fc8d59', '#d73027'),
            6: ('#1a9850', '#66bd63', '#d9ef8b',
                '#fee08b', '#fc8d59', '#d73027'),
            7: ('#1a9850', '#66bd63', '#d9ef8b', '#ffffbf',
                '#fee08b', '#fc8d59', '#d73027'),
            8: ('#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                '#fee08b', '#fdae61', '#f46d43', '#d73027'),
            9: ('#1a9850', '#66bd63', '#a6d96a', '#d9ef8b', '#ffffbf',
                '#fee08b', '#fdae61', '#f46d43', '#d73027'),
            10: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#fee08b', '#fdae61', '#f46d43', '#d73027', '#a50026'),
            11: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#ffffbf', '#fee08b', '#fdae61', '#f46d43', '#d73027',
                 '#a50026'),
            12: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#e7ef88', '#ffffbf', '#fee08b', '#fdae61', '#f46d43',
                 '#d73027', '#a50026'),
            13: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#e7ef88', '#ffffbf', '#fee08b', '#fdae61', '#f46d43',
                 '#d73027', '#bb2921', '#a50026'),
            14: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#e7ef88', '#ffffbf', '#fff6a0', '#fee08b', '#fdae61',
                 '#f46d43', '#d73027', '#bb2921', '#a50026'),
            15: ('#006837', '#1a9850', '#66bd63', '#a6d96a', '#d9ef8b',
                 '#e7ef88', '#ffffbf', '#ffffbf', '#fff6a0', '#fee08b',
                 '#fdae61', '#f46d43', '#d73027', '#bb2921', '#a50026'),
            16: ('#006837', '#1a9850', '#66bd63', '#a6d96a',
                 '#d9ef8b', '#e7ef88', '#ffffbf', '#ffffbf', '#ffffbf',
                 '#fff6a0', '#fee08b', '#fdae61', '#f46d43', '#d73027',
                 '#bb2921', '#a50026'),
            }[nb_features]