Minutes of Meeting, Web Coverage Tile Service SWG

Attendees

• Roger Brackin (RB) Envitia Ltd
• Chris Little (CL) MetOffice
• Jeff Yutzler (JY) Image Matters LLC

Discussion

GeoPackage Encoding of Terrain

JY described the plans to move forward with a terrain encoding for GeoPackage. Currently TIFF is the preferred option. Only 2D scalar properties will be supported. JY is preparing a paper summarising the proposed implementation.. RB also engaged in the GeoPackage SWG discussions. JY will assemble an initial strawman in the next few weeks. Synergies were likely so the two groups should stay close in terms of discussions.

Use Cases

It was agreed that we should look at the WCS MetOcean extension use cases (Pete Trevelyan) as there may be key elements in these. It was agreed that the SWG should start slowly through the key requirements:

• Scalars
• Vectors
• Single level, multilevel
• Single time to multi-time
• Asynchronous aspect

One key performance requirement is a URI for each tile (so its cachable in the web fabric)

Encoding Discussion

Possible encodings include:

• TIFF
• NetCSV
• GRIB
• CSV
• JSON *JPEG/JP2000

Other Points

Any service should be WMTS Friendly - Align where possible. We may stick to one tileset though. We also need to look at WMTS Simple Profile.

GeoPackage

- In Geopackage the proposal is to register Gridded values, Null value Value No data value. Missing. - Masks - Tiff images do support these to minimise irrelevant data. Discuss (Tiff image masks).