middle.py 文件源码

def get_position_geohash(points):
    """ This takes points and with these points find out what geohash each falls
        under. Then we could get the crime_index and total_crimes
    """

    # takes in a list as a parameter of [(lat, lng) ... (lat, lng)]
    coords_data = []  # to store the dictionary generated

    # do something like a for loop over here
    for point in points:
        geohash_sql = "SELECT * " + \
                      "FROM nyc_crimes_by_geohash " + \
                      "WHERE geohash=" + \
                      "ST_GeoHash(st_makepoint(%s, %s), 7);" % \
                      (point[0], point[1])

        # execute the raw sql, and there should only be one result... so get that.
        geohash_query = db.engine.execute(geohash_sql).fetchone()

        if geohash_query is None:
            # if the geohash isn't found, need to do something,
            # query PostGIS for the geohash (not in db)
            # then assume that there are no crimes in the area
            geohash_of_point = "SELECT ST_GeoHash(geometry(Point(%s, %s)), 7);" \
                % (point[0], point[1])

            geohash_found = db.engine.execute(geohash_of_point).fetchone()

            geohash_query = [0, geohash_found[0], 0, 0.0]

        geohash_query_data = {
            'geohash': geohash_query[1],
            'total_crimes': geohash_query[2],
            'crime_index': float(geohash_query[3]),
            'point': point
        }
        coords_data.append(geohash_query_data)

    # return something like [{dicte}, {dictw}], or {dict}, based on total pts
    return coords_data