mbtile2geojson.py

#!/usr/bin/python3
# encoding: utf-8
'''
Created on 28.08.2018

@author: stevo
'''
import os
from optparse import OptionParser
import geojson
from geojson.feature import Feature
from geojson.geometry import Polygon
from pathlib import Path
from Utils.Helper import HandleDate
from Utils.Mobac import ExtractMapsFromAtlas
from Utils.convex_huell import convexhull
from Utils.filesystem import GetFileList
import sys

# this script generates a geojson file for open sea map download layer

# smaple geo json file:
# https://wiki.openseamap.org/wiki/OpenSeaMap-dev:De:Chart_Download_Layer

if __name__ == '__main__':

    parser = OptionParser()
    usage = "usage: %creator [options] arg1 arg2"
    atlas = list()

    parser.add_option("-u", "--url", type="string", help="server address", dest="url", default="https://ftp.gwdg.de")
    parser.add_option("-d", "--dir", type="string", help="json file directory on server", dest="InPath", default="/pub/misc/openstreetmap/openseamap/charts/kap")
    parser.add_option("-f", "--filename", type="string", help="filename of the mbtile file archive", dest="archivfilename", default="./sample/mbtiles/")
    parser.add_option("-p", "--project", type="string", help="filename of the chart bundler project file", dest="ProjectFile", default="sample/atlas/osmcb/sea/osmcb-catalog-Adria.xml")
    parser.add_option("-z", "--zoom", type="int", help="zoom level", dest="zoom", default=12)

    options, arguments = parser.parse_args()

    # determine filename of 7z archive with kap data

    # check if file exists
    my_file = Path(options.archivfilename)
    if my_file.is_file():
        archivfilename = options.archivfilename
    elif my_file.is_dir():
        # search for file
        print("parameter --filename points to valid directory".format(options.archivfilename))
        filelist = GetFileList(options.archivfilename, filterval=".mbtiles")
        if len(filelist) is 1:
            archivfilename = filelist[0]
        else:
            print("error invalid parameter for --filename detected 2: {}".format(options.archivfilename))
            sys.exit(1)
    else:
        print("error invalid parameter for --filename detected 1: {}".format(options.archivfilename))
        sys.exit(1)
    # directory exists

    # get timestamp from filename of the kap file archive
    date = archivfilename[-21:-8]
    date = HandleDate(date)

    # get size ( from kap file archive )
    filesize = os.path.getsize(archivfilename)

    # get chart name ( from project file )
    atlas, mapname = ExtractMapsFromAtlas(options.ProjectFile)

    # create polygon ( from project file )
    points = list()
    for chart in atlas:
        # print(area)
        if(chart.zoom >= options.zoom):

            # hack for SouthPacificIslands
            if mapname == "SouthPacificIslands":
                if chart.NE.lon > 0:
                    chart.NE.lon -= 360
                if chart.NW.lon > 0:
                    chart.NW.lon -= 360
                if chart.SE.lon > 0:
                    chart.SE.lon -= 360
                if chart.SW.lon > 0:
                    chart.SW.lon -= 360

            points.append((chart.NE.lon, chart.NE.lat))
            points.append((chart.NW.lon, chart.NW.lat))
            points.append((chart.SE.lon, chart.SE.lat))
            points.append((chart.SW.lon, chart.SW.lat))
        else:
            print("skip chart {}".format(chart.name))

    huell = convexhull(points)
    huell.append(huell[0])

    outfilename = archivfilename[:-7] + 'geojson'

    url = "{}{}/{}".format(
        options.url,
        options.InPath,
        os.path.basename(archivfilename))

    # generate geojson object
    jsonres = Feature(geometry=Polygon([huell]),
                      properties={"name:en": mapname,
                                  "format": "mbtile",
                                  "app": "opencpn",
                                  "app:url": 'https://opencpn.org/',
                                  "url": url,
                                  "date": date,
                                  "filesize": filesize})

    # print created geojson object to output file
    with open(outfilename, 'w') as f:
        f.write(geojson.dumps(jsonres, indent=4, sort_keys=True))