# -*- coding: utf-8 -*-
"""Membuat web map statis (Leaflet + GeoJSON) dari data KPH Contoh. Penulis: Badar Mubarok Yogaswara
Hanya membuat berkas lokal di folder keluaran/peta_web. Tidak mengunggah apa pun.
Jalankan: python-qgis.bat buat_peta_web.py
"""
import json, math, os
os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
from qgis.core import (QgsApplication, QgsVectorLayer, QgsCoordinateReferenceSystem,
QgsVectorFileWriter, QgsCoordinateTransform, QgsCoordinateTransformContext)
AQ = os.path.dirname(os.path.abspath(__file__))
DATA = os.path.abspath(os.path.join(AQ, "..", "..", "..", "data-sintetis"))
OUT = os.path.join(AQ, "keluaran", "peta_web")
def ke_tile(lon, lat, zoom):
"""Nomor ubin XYZ (skema web: x ke timur, y ke selatan) untuk satu titik."""
n = 2 ** zoom
x = int((lon + 180.0) / 360.0 * n)
y = int((1.0 - math.asinh(math.tan(math.radians(lat))) / math.pi) / 2.0 * n)
return x, y
def ekspor(layer_path, nama_layer, berkas):
lyr = QgsVectorLayer(layer_path, nama_layer, "ogr")
assert lyr.isValid(), layer_path
opsi = QgsVectorFileWriter.SaveVectorOptions()
opsi.driverName = "GeoJSON"
opsi.fileEncoding = "UTF-8"
opsi.ct = QgsCoordinateTransform(
lyr.crs(), QgsCoordinateReferenceSystem("EPSG:4326"), QgsCoordinateTransformContext())
opsi.layerOptions = ["COORDINATE_PRECISION=6", "RFC7946=YES"]
hasil = QgsVectorFileWriter.writeAsVectorFormatV3(lyr, berkas, QgsCoordinateTransformContext(), opsi)
assert hasil[0] == QgsVectorFileWriter.WriterError.NoError, hasil
return lyr.featureCount()
HTML = """
Peta KPH Contoh
"""
if __name__ == "__main__":
app = QgsApplication([], False)
app.initQgis()
os.makedirs(OUT, exist_ok=True)
n1 = ekspor(os.path.join(DATA, "paket-m4", "Petak_KPH.gpkg"), "Petak_KPH", os.path.join(OUT, "petak.geojson"))
n2 = ekspor(os.path.join(DATA, "paket-data", "Hotspot_Nasional.gpkg"), "Hotspot", os.path.join(OUT, "hotspot.geojson"))
with open(os.path.join(OUT, "index.html"), "w", encoding="utf-8") as fh:
fh.write(HTML)
print("petak:", n1, "hotspot:", n2)
for b in ("petak.geojson", "hotspot.geojson"):
d = json.load(open(os.path.join(OUT, b), encoding="utf-8"))
c = d["features"][0]["geometry"]["coordinates"]
while isinstance(c[0], list):
c = c[0]
print(b, "fitur:", len(d["features"]), "koordinat pertama (lon, lat):", c)
print("ubin zoom 0 untuk (0,0):", ke_tile(0, 0, 0), "| zoom 1 untuk (0,0):", ke_tile(0, 0, 1),
"| zoom 10 Jakarta -6.2,106.85:", ke_tile(106.85, -6.2, 10))
app.exitQgis()