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Tile Converter

Prepare big rasters, tile archives and point clouds for DropMaps — convert GeoTIFF and MBTiles to COG and PMTiles, and LAS/LAZ to 3D Tiles, locally.

The DropMaps Converter is a small, free desktop app that prepares large rasters and tile archives for DropMaps. It turns ordinary GeoTIFFs and MBTiles into the cloud-streaming formats the web app reads best — Cloud-Optimized GeoTIFF (COG) and PMTiles — right on your own machine, with no upload and no file-size ceiling.

What it does

  • GeoTIFF / TIFF → COG — adds internal tiling and overviews (and reprojects if needed) so big rasters and drone orthomosaics stream fast in DropMaps. COG keeps the original bands, so you can still restyle imagery and single-band data in the app.
  • MBTiles → PMTiles — repacks an MBTiles archive into a single portable PMTiles file (no re-rendering).
  • PMTiles output (opt-in) — for visual/RGB overlays you can choose PMTiles instead of COG.
  • LAS / LAZ → .3tz — tiles a point cloud (in any coordinate system that’s recorded in the file) into a 3D Tiles archive that DropMaps streams with level of detail. DropMaps doesn’t load raw LAS/LAZ, so convert point clouds here first.
  • 3D Tiles → .3tz — packs a 3D Tiles tileset (a folder, a .zip or an existing .3tz) into one indexed .3tz file to drop into DropMaps.
  • Runs locally — everything converts on your computer. Nothing is uploaded, and there’s no file-size limit, so it handles multi-gigabyte rasters the in-browser tools can’t. Output files are written next to the source.

Why convert?

DropMaps streams COG and PMTiles over the web via HTTP range reads, so only the part of the map you’re looking at is fetched. Converting a plain GeoTIFF to COG (or an MBTiles to PMTiles) up front means the layer loads quickly in the browser and can be backed up to the cloud and streamed to your other devices. See Supported formats for how each format is read.

Get the Converter

Installers for Windows, macOS (Apple Silicon) and Linux are on the Tools page. It’s free, needs no account, and works offline once installed.

Files that are already COG, PMTiles or .3tz can be dropped straight into the app — no conversion needed.

Good to know

  • Conversion is local and free — there’s no server cost, so there’s no file-size cap.
  • A raster needs a coordinate system to be placed on the map. If a GeoTIFF relies on sidecar files (.prj, .tfw/.wld), keep them in the same folder as the .tif.
  • COG is the default for rasters because it preserves bands and stays close to the original size; PMTiles bakes in RGB and is best reserved for visual overlays.

Next steps