def get_node_gps_point(way_id, index):
cur = connect(LATLONG_DBNAME)
qstring = 'SELECT ST_AsText(way) FROM planet_osm_line WHERE osm_id = {0}'.format(way_id)
cur.execute(qstring)
rows = cur.fetchall()
if not len(rows) or not len(rows[0]):
return (None, None)
points = utils.linestring_to_point_array(rows[0][0])
return points[index] if len(points) else None
def query_ways_within_radius(lat, lon, radius):
cur = connect(DBNAME)
# PostGIS format of a point. Long/Lat as this stage:
pointstr = "'POINT({0} {1})'".format(lon, lat)
# PostGIS function to generate a point from text:
pointgenstr = 'ST_PointFromText({0}, {1})'.format(pointstr, 4326)
# PostGIS function to transform point from lat/long to mercator:
point_in_merc_str = 'ST_Transform({0}, {1})'.format(pointgenstr, 900913)
# Build query string from the pieces:
qstring = """SELECT ST_AsText({1}), osm_id, ST_AsText(way), oneway
FROM {0} WHERE ST_DWithin(way, {1}, {2})""".format(LINE_TABLE,
point_in_merc_str,
radius)
cur.execute(qstring)
rows = cur.fetchall()
# First cell of each row is the point in mercator projection as text.
# Making the PostGIS database do the lat/long -> mercator conversion.
# The point is in form 'POINT(long, lat)' so extract the floating point coordinates
# with regex
if not rows:
return None, None
point_in_merc = re.findall(r"[-+]?\d*\.\d+|\d+", rows[0][0])
point_in_merc = [float(d) for d in point_in_merc]
ways = []
for row in rows:
# second element of each row is the osm_id of the way
osm_id = row[1]
if osm_id < 0:
continue
oneway = True if row[3] == 'yes' else False
# third element of each row is the linestring of the way as a string.
# call linestring_to_point_array to convert the string into an array of points
point_array = utils.linestring_to_point_array(row[2])
way = {'osm_id': osm_id, 'points': point_array, 'oneway': oneway}
ways.append(way)
return point_in_merc, ways
