An extract refers to the process of obtaining data from DSS files or a WISKI database (KiWIS Write Extension) and mapping that data to a model alternative's required input record. The extract retrieves the source data and copies the data into records stored in a centralized DSS file called the forecast.dss file. The forecast.dss file is then used to provide input data during the forecast compute process. Extracts can contain both gridded data and time series data.