Data types and management

PRAGA supports two main meteorological data types: point data and gridded data. Several gridding procedures are included for interpolating point data to gridded datasets. Point and gridded data share climatological analysis tools and most of the statistics tools. Two data frequencies are currently supported: hourly and daily.

In Praga distribution data folder examples of DEM, point data DB, grid data XML files, interpolation proxy maps and Projects are available for testing.

Meteo data

Point data

Point data are locally stored in SQLite databases. You can create new point databases using the template /DATA/TEMPLATE/template_meteo.db. Station metadata are listed in the point_properties table, variables are described and coded in the variable_properties table, while data for each station are stored in separate XXXX_Y tables, where XXXX is the station ID and Y is the frequency code (D for daily, H for hourly data). Following these templates, you can create and populate your own database.

Point data are also downloadable from Arkimet within Arpae network, by using the template /DATA/TEMPLATE/template_meteo_arkimet.db.

Gridded data

Gridded data are stored in MySQL databases. Grid datasets are managed by PRAGA by using XML files, which contain information on database server, grid geometry, and data structures for each data frequency. Examples of XML file are found in the the distribution meteogrid folder.
The main information included in a XML grid file are the following:

• connection: information for connecting to the mySql database
• gridstructure: information on grid structure. isregular, isutm, istin specify whether the grid has a fixed resolution in x and y, whether it is in metric (UTM) or geographic (latitude and longitude) coordinates, whether is a Triangular Irregular Network (TIN) grid, respectively. isfixedfields specifies whether the tables containing data have fixed fields (one fixed field for each variable) or they include a varCode field containing variable codes.
• tabledaily: information on tables containing daily data. If isfixedfields is false, you have to specify variable codes and PRAGA names for each variable.
• tablehourly: same as above for hourly data.

PRAGA contains several function to interpolate point data to grid (gridding), using spatial interpolation specifically devised for each variable. See Gridding for a detailed documentation.

Geographical data

Geographical data are read by Praga as raster files (e.g. in ESRI .flt binary format) in EPSG 32632.

Digital Elevation Model

Praga uses Digital Elevation Model (DEM) for several meteorological analysis (e.g. gridding point data, estimating solar radiation).

Other layers

Other GIS maps could be read by Praga for example if additional geographical layers are to be used for detrending point data, when gridding.