openseamaps-mbtiles/2017/ostsee.mbtiles Download funktioniert nicht

[IlmariKrebs]

Das Format von openseamaps-mbtiles/2017/ostsee.mbtiles scheint unvollständig zu sein.
Die Tabelle metadata ist leer in der Datei, die routeconverter herunterlädt.
Wenn man diese Tabelle manuell füllt. Erhält man ein funktionstüchtiges Overlay.

Eventuell diese Datei nicht mehr zum Download anbieten oder durch eine neuere ersetzen.

Viele Grüße,

Ilmari

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Ich habe versucht die openseamaps-mbtiles Ostsee herunterzuladen. Am Ende des Downloads kommt eine Fehlermeldung.
Der Eintrag ist aber dennoch vorhanden und wenn man versucht diese auszuwählen erhalte ich diese Fehlermeldung + Copilot Erklärungsversuch

Cannot display map 'openseamaps-mbtiles/2017/ostsee.mbtiles':
java.lang.IllegalArgumentException: 'metadata.format' field was not found. ...

die ostsee.mbtiles Datenbank enthält eine metadata Tabelle die ist aber leer.

Here’s what that error message means, broken down clearly and specific to RouteConverter and MBTiles.

---

What the message says (verbatim)

Cannot display map

Code:

openseamaps-mbtiles/2017/ostsee.mbtiles

:
java.lang.IllegalArgumentException:

Code:

metadata.format

field was not found. Is this an MBTiles database?

---

Plain‑English explanation
RouteConverter did open the

Code:

.mbtiles

file, but then discovered that:
➡️ The file does NOT contain a required MBTiles metadata entry called

Code:

format

.
Because of that, RouteConverter refuses to treat it as a valid MBTiles map and cannot render it.
In short:

The file is either not a valid MBTiles file, or it is an incomplete / non‑standard MBTiles database.

---

Why this happens (important)
MBTiles is not just “tiles in a SQLite file”.
It must contain a table called

Code:

metadata

with specific keys.
RouteConverter (via Mapsforge/MBTiles reader) expects at least:

• Code:

  metadata.name
• Code:

  metadata.type
• ✅
  
  
  Code:

  metadata.format
  ← this one is missing
  
• Code:

  metadata.minzoom
  ,
  
  
  Code:

  maxzoom
  , etc.
  

If

Code:

metadata.format

is missing, Java throws exactly this exception:

Code:

IllegalArgumentException: 'metadata.format' field was not found

[forum.rout...verter.com]

---

Very common causes
1️⃣ File is not actually MBTiles
Some files:

• Are SQLite databases, but not MBTiles
  
• Or are custom MBTiles variants created by older or niche tools
  

RouteConverter is strict and will reject them.

---

2️⃣ File was generated incorrectly
Some tile exporters (especially older OpenSeaMap / OSM tools) omit

Code:

metadata.format

, even though other apps tolerate it.
RouteConverter does not. [forum.rout...verter.com]

---

3️⃣ File is corrupted or incomplete
If the

Code:

.mbtiles

file was:

• Interrupted during creation
  
• Partially copied
  
• Truncated
  

…the metadata table may be missing entries.

---

How to verify (quick check)
If you open the file with any SQLite viewer and run:
SELECT * FROM metadata;
You should see a row like:

Code:

name | format | png

If

Code:

format

is missing → this exact error is expected.

---

What will NOT fix it

• Updating Java
  
• Restarting RouteConverter
  
• Internet connection
  
• OpenStreetMap tile policy (this error is offline, not network‑related)
  

---

Practical solutions
✅ Best solution
Re‑create the MBTiles file using a tool that writes standards‑compliant MBTiles, e.g.:

• Code:

  mb-util
• Code:

  tilemaker
• Code:

  MapTiler
• Code:

  osmosis
  → MBTiles output
  

---

✅ Quick workaround (advanced)
If the file does contain tiles, you can manually add the missing metadata:

INSERT INTO metadata (name, value) VALUES ('format', 'png');
``

(or

Code:

jpg

, depending on the tiles)
⚠️ Only do this if you know the tile image format.

---

✅ RouteConverter‑native alternative
RouteConverter works best with:

• Mapsforge
  
  
  Code:

  .map
  files
  
• Its built‑in online map sources
  

MBTiles support is limited and picky by design. [forum.rout...verter.com]

---

Summary (one‑liner)

RouteConverter cannot display your map because the

Code:

.mbtiles

file is missing the mandatory

Code:

metadata.format

entry, so it does not qualify as a valid MBTiles database.

If you want, you can tell me:

• Where you got
  
  
  Code:

  ostsee.mbtiles
  from, or
  
• Which tool created it
  

…and I can tell you exactly how to regenerate or repair it correctly for RouteConverter.