Improving the visualisation of statistics: The need for an SDMX-based visualisation framework Xavier Sosnowska Luxembourg, 6 May 2008

2 ECB developments in visualisation tools (exchange rates, yield curves) Improved communication towards the public (improved visualisation, accessibility and understanding of data). Very popular (rather high usage). But "ad hoc" applications (structure of data is "hard coded" into the application). Inefficient, low code reusability and scalability issue. => Need for a generic reusable visualisation framework

3 The ECB SDMX visualisation framework From May 2007 to February 2008 Based on the SDMX standard: –ISO standard (ISO/TS 17369), sponsored by 7 international institutions (including the ECB) –SDMX information model describes all artefacts needed –Already in use in all layers of the ECB Statistical environment –Supports for various XML formats (SDMX-ML)

4 The ECB SDMX visualisation framework Approx lines of code, covered by more than 700 unit tests Based on 3 layers: 1.The readers: Reads the Data Structure Definitions and the data files (SDMX-ML Structure and Compact formats) 2.The model: translation of the extracted data into artefacts of the SDMX Information Model 3.The views: visualisation of the objects of the SDMX information model

5 The SDMX-ML readers (1) Parses SDMX-ML structure files and extracts code lists, concept schemes, organisation schemes, data flows and key families. Parses SDMX-ML data files and extracts data sets, groups, series and observations. Uses the information available in the structure file to interpret the data. Translates the extracted data into objects of the SDMX information model Around 30 classes and 2500 lines of code Modular code: possibility to add readers for other SDMX-ML formats (e.g.: SDMX-ML Generic format)

6 The SDMX-ML readers (II)

7 The SDMX Information model (I) Stores in memory the data extracted from the SDMX-ML files Represents the extracted data as artefacts of the SDMX information model (codes and code lists, key families, series, observations, etc.) A bit more than 100 classes and 5500 lines of code

8 The SDMX Information model (II)

9 The visual display (I) Visually displays the objects of the SDMX information model Various views are possible (Line charts, column charts, tables, metadata panels, various filters, etc). Possibility to combine views on a screen Follows the Model-View-Controller pattern and implements a few other design patterns (Command, Abstract Factory, Singleton, Observer, etc.) Around 50 classes and 5500 lines of code

10 The visual display (II)

11 SDMX framework: Expected uses Development of a quick prototype (“proof-of- concept”) on top of the ECB Flex SDMX framework: The SDMX browser. Could potentially become an SDMX Web services client. The SDMX browser Other expected uses (later in 2008): –ECB Statistics Dashboard (e.g.: inflation) –Charts on the Statistical Data Warehouse and the ECB website ECB website