Convert XYZ to TMS

xyz_to_tms_converter.py

import os
import shutil
from xml.etree.ElementTree import Element, SubElement, ElementTree
import argparse

# Mercator projection measures the Earth in meters, and the TMS format uses a specific tiling scheme.

EARTH_CIRCUMFERENCE = 40075016.68557849  # in meters
TILE_SIZE = 256  # in pixels

def convert_xyz_to_tms(xyz_dir, tms_dir, max_zoom, inplace=False):
    for z in range(max_zoom + 1):
        z_path = os.path.join(xyz_dir, str(z))
        if not os.path.isdir(z_path):
            continue

        print(f"[Z={z}] Processing...")
        for x in os.listdir(z_path):
            x_path = os.path.join(z_path, x)
            if not os.path.isdir(x_path):
                continue

            for y_file in os.listdir(x_path):
                y_name, ext = os.path.splitext(y_file)
                if not y_name.isdigit():
                    continue

                xyz_y = int(y_name)
                tms_y = ((1 << z) - 1) - xyz_y # 2^z - 1 is the maximum y value at zoom level z
                new_file = f"{tms_y}{ext}"

                src_path = os.path.join(x_path, y_file)
                dst_x_path = os.path.join(tms_dir if not inplace else x_path, str(z), x) if not inplace else x_path
                dst_path = os.path.join(dst_x_path, new_file)

                os.makedirs(dst_x_path, exist_ok=True)

                if inplace:
                    if src_path != dst_path:
                        os.rename(src_path, dst_path)
                else:
                    shutil.copy2(src_path, dst_path)


def generate_tilemapresource_xml(output_path, tile_format, max_zoom):
    root = Element("TileMap", version="1.0.0", tilemapservice="http://localhost/")
    SubElement(root, "Title").text = "TMS Tiles"
    SubElement(root, "Abstract")
    SubElement(root, "SRS").text = "EPSG:3857"
    SubElement(root, "BoundingBox", minx="-20037508.34", miny="-20037508.34",
               maxx="20037508.34", maxy="20037508.34")
    SubElement(root, "Origin", x="-20037508.34", y="-20037508.34")
    SubElement(root, "TileFormat", attrib={"width": str(TILE_SIZE), "height": str(TILE_SIZE), "mime-type": f"image/{tile_format}", "extension": tile_format})

    tilesets = SubElement(root, "TileSets", profile="global-mercator")
    for z in range(1, max_zoom + 1):
        #upp = 156543.03392804097 / (2 ** z)
        upp = EARTH_CIRCUMFERENCE / (TILE_SIZE * (2 ** z))  # Units per pixel at zoom level z
        SubElement(tilesets, "TileSet", attrib={"href": str(z), "units-per-pixel": str(upp), "order": str(z)})

    tree = ElementTree(root)
    tree.write(output_path, encoding="utf-8", xml_declaration=True)
    print(f"Generated tilemapresource.xml at {output_path}")


def main():
    parser = argparse.ArgumentParser(description="Convert XYZ tiles to TMS format.")
    parser.add_argument("input_dir", help="Path to the XYZ directory")
    parser.add_argument("max_zoom", type=int, help="Maximum zoom level")
    parser.add_argument("--inplace", action="store_true", help="Convert in place")
    parser.add_argument("--output-dir", help="Output directory (if not inplace)")
    parser.add_argument("--tile-format", default="png", choices=["png", "jpeg", "jpg"], help="Tile image format")

    args = parser.parse_args()

    if args.inplace:
        tms_dir = args.input_dir
    else:
        if not args.output_dir:
            parser.error("Must specify --output-dir when not using --inplace")
        tms_dir = args.output_dir

    convert_xyz_to_tms(args.input_dir, tms_dir, args.max_zoom, inplace=args.inplace)

    xml_path = os.path.join(tms_dir, "tilemapresource.xml")
    generate_tilemapresource_xml(xml_path, tile_format=args.tile_format, max_zoom=args.max_zoom)


if __name__ == "__main__":
    main()