The data access is handled by a system of plugins. They all offer the same interface, meaning that a plugin can transparently be replaced by another one. Since they might rely on third party libraries for accessing the data, they have been created as plugins, that is they are only compiled if requested when configuring the compilation with cmake. A plugin can therefore fail to run if it has not been compiled.

Writing a file happens via a wrapper for std::ofstream ofilestream that adds some functionality, like limiting the write access.

Please have a look at the support for coordinate systems.

Data sources categories

Several data sources categories have been defined that can be provided by a different plugin. Each data source category is defined by a specific key in the configuration file (usually, io.ini):

METEO, for meteorological time series
DEM, for Digital Elevation Maps
LANDUSE, for land cover information
GRID2D, for generic 2D grids (they can contain meteo fields and be recognized as such or arbitrary gridded data)
POI, for a list of Points Of Interest that can be used for providing extra information at some specific location (extracting time series at a few selected points, etc)

A plugin is "connected" to a given data source category simply by giving its keyword as value for the data source key:

METEO = SMET

DEM = ARC

Each plugin might have its own specific options, meaning that it might require its own keywords. Please check in each plugin documentation the supported options and keys (see links below). Moreover, a given plugin might only support a given category for read or write (for example, PNG: there is no easy and safe way to interpret a given color as a given numeric value without knowing its color scale, so reading a png has been disabled). Finally, the plugins usually don't implement all these categories (for example, ArcGIS file format only describes 2D grids, so the ARC plugin will only deal with 2D grids), so please check what a given plugin implements before connecting it to a specific data source category.

Available plugins

So far the following plugins have been implemented (by keyword for the io.ini key/value config file). Please read the documentation for each plugin in order to know the plugin-specific keywords:

Plugin keyword	Provides		Description	Extra requirements
	Input	Output
A3D	meteo, poi	meteo	original Alpine3D meteo files
ALPUG	meteo		data files generated by the ALPUG meteo stations
ARC	dem, landuse, grid2d	grid2d	ESRI/ARC ascii grid files
ARGOS	meteo		ARGOS satellite raw files - plugin not functional yet!
ARPS	dem, grid2d, grid3d		ARPS ascii formatted grids
BUFRIO	meteo		BUFR meteo files	ecCodes
COSMOXML	meteo		MeteoSwiss COSMO's postprocessing XML format	libxml2
CSV	meteo		flexible reading of CSV files
DBO	meteo		connects to SLF's DBO web service interface	libcurl
GEOTOP	meteo	meteo	GeoTop meteo files
GOES	meteo		Meteo files transmitted by the GOES satellites
GRASS	dem, landuse, grid2d	grid2d	Grass grid files
GRIB	meteo, dem, grid2d		GRIB meteo grid files	ecCodes
IMIS	meteo		connects to the IMIS database	Oracle's OCCI library
METEOBLUE	meteo		connects to MeteoBlue's web API	libcurl
MYSQL	meteo		connects to a MySQL database, various schemas are supported	MySQL's C API
NETCDF	meteo, dem, grid2d	meteo, grid2d	NetCDF grids and timeseries	NetCDF-C library
iCSV	meteo, poi	meteo	iCSV data files
OSHD	meteo		OSHD generated binary Matlab files	libmatio
PGM	dem, grid2d	grid2d	PGM grid files
PMOD	meteo		Raw data files from Pmod/Wrc (experimental!)
PNG		grid2d	PNG grid files	libpng
PSQL	meteo	meteo	connects to PostgreSQL database	PostgreSQL's libpq
SASE	meteo		connects to the SASE database	MySQL's C API
SMET	meteo, poi	meteo	SMET data files
SNOWPACK	meteo	meteo	original SNOWPACK meteo files
SYNTH	meteo		synthetic data generation
ZRXP		meteo	WISKI database input files

Note: In order to optimize the data retrieval, the raw data is buffered. This means that up to BUFFER_SIZE days of data will be read at once by the plugin so subsequent reads will not have to get back to the data source (this key is in the [General] section). It is usually a good idea to configure BUFFER_SIZE to the intended duration of the simulation (in days).

Multiple data sources

It is possible to use multiple plugins to read meteorological timeseries from multiple sources and combine them into one stream of data. This is achieved by declaring as many [Input#] sections as necessary (where # represent any number, to make sure that not two sections have the same name) and declaring METEO plugins in each of them. Please make sure that all required keys are defined within each new such section (such as TIME_ZONE) because the plugins created this way won't have access to the other [Input] sections. The other plugins (such as for reading grids, dem, etc) will only be read from the standard [Input] section and performed as usual after the data has been provided by the plugins.

If reading the same station from multiple sources (for example providing different time coverage), it might be useful to use the EditingAutoMerge feature to merge all streams belonging to a station into one single stream. In this case, the data coming from [Input] has priority over the various [Input#] data sources.