HDF5 is a binary self-describing container for scientific data with a filesystem inside the file: groups (folders), datasets (arrays), attributes (metadata). On osm2cdr the .h5 export works honestly like this: each OSM layer becomes an HDF5 group holding longitude and latitude datasets (feature centroids) plus one dataset per attribute field as strings. It is a self-describing container of coordinates and attributes, not a gridded scoring raster or DEM cube — the exporter does not compute such layers. Written via h5py; readable in h5py, HDFView, MATLAB, R, IDL.
Key Features

What Program Opens HDF5 Files
The following programs and applications can open, edit, and work with HDF5 (Hierarchical Data Format v5) (.h5) files exported from OSM2CDR:
Format specifications
- Open standard
- 2D only
- Lossless (no quality loss)
- Stores feature attributes
- Output: 1 file
- One HDF5 group per layer holding lon/lat centroid datasets plus one string dataset per attribute; a self-describing container, not a gridded raster cube. Fallback to gzip-JSON.
Who Uses HDF5 Maps
How to Export HDF5
Popular maps in HDF5
Get HDF5 (Hierarchical Data Format v5) map exports
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