NetCDF (Network Common Data Form)
Open BetaNetCDF is a self-describing binary format for scientific data and the de facto standard in climate science, oceanography, and satellite remote sensing (ERA5, CMIP6, MODIS). On osm2cdr the OSM to .nc export works honestly like this: for each layer we take feature centroids (longitude/latitude) plus their attributes and write them through xarray as variables sharing a feature-index axis. The result is a compact point dataset with metadata (title, source, bbox), not a ready-made climate density grid cube — that would require a separate aggregation step. The file opens in xarray, Panoply, GDAL, and any NetCDF tool.
Key Features
About NetCDF Format
NetCDF is a self-describing binary container for scientific data: along with the numbers it holds variable names, dimensions and attributes, so the file can be read without external schemas and many years later. In climatology, oceanography and remote sensing it is the working standard — ERA5, CMIP6 and MODIS products are distributed in it.
Exporting OSM into .nc is needed where city objects have to end up in the same pipeline as scientific data: mixing points of interest into a climate sample in xarray, attaching a slice of terrain to a study, practising on real data with CDO, NCO and ncdump.
The export is arranged honestly and simply: for each layer the centroids of the objects (longitude and latitude) and their attributes are taken and written through xarray as variables on a common object-index axis; layers are merged into one file with the global attributes title, source and the area bounds. This is a point dataset, not a ready gridded density cube — a cell grid has to be built by a separate aggregation. The shape of polygons and lines is not preserved in such a transfer: if you need geometry, take GeoJSON or GeoPackage.
What Program Opens NetCDF Files
The following programs and applications can open, edit, and work with NetCDF (Network Common Data Form) (.nc) files exported from OSM2CDR:
Format specifications
- Open standard
- 2D only
- Lossless (no quality loss)
- Stores feature attributes
- Output: 1 file
- A single .nc written via xarray: feature centroids (lon/lat) and attributes share a feature-index axis; a point dataset with metadata, not a density grid cube.
Who Uses NetCDF Maps
How to Export NetCDF
How to Open After Export
- Panoply (free, NASA GISS) — open the .nc and quickly see which variables and how many objects are inside, without writing any code.
- Python and xarray — xarray.open_dataset("map.nc") and then the usual work with a dataset: slices, merging with your own arrays, export into other formats.
- ncdump -h map.nc — show the file structure in a terminal in a second: variables, dimensions, global attributes.
- CDO and NCO — if the file has to be mixed into an existing climate pipeline: merging, cropping, renaming variables.
- QGIS through the GDAL NetCDF driver — a visual check that the points landed where they were expected on the map.
Popular maps in NetCDF
Get NetCDF (Network Common Data Form) map exports
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