Improving the visualisation of statistics

The use of SDMX-ML as input for dynamic graphs

Gérard Salou, Xavier SosnovskyEuropean Central Bank

Brussels, 2009-02-19

2

Agenda

• Objectives of the developments• The 1st phase - Initial applications (2007)• The 2nd phase - The need for an SDMX-based

visualisation framework (2008)• The 3rd phase - The ECB inflation dashboard (2008)• The road ahead

3

Objectives of the development

Further improve our communication on statistics

Improve data visualisation in order to facilitate understanding of statistics

Leverage IT usage: new web technologies as well as users’ computers.

4

The situation in 2007

Two interactive visualisation applications (using Adobe Flash) published on the ECB web site in 2007:

• Bilateral exchange rates (2007-04)• Euro area yield curves (2007-07)

Data published in SDMX-ML v2 Compact format

5

Exchange rates: Improvements

Most popular section on the ECB website. Improved both data accessibility and visualisation.

• More information (latest observation, growth rates)

• Hovering functionality that shows the value for each

observation

• Possibility to view data for predefined periods

• Possibility to define own period (period slider)

• Possibility to switch base currency

6

Basic calculations

Change base

ValuesZoom

Zoom and slide

7

Euro area yield curves

Second Adobe Flex application in production since July 2007.

8

Multiple choices

Animation

Table view

Zoom

9

Animation parameters

10

Advantages and disadvantages

• 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

11

Solution? An SDMX visualisation framework

• Develop libraries that can be used to build visualisation tools for statistical data and metadata

• Written in ActionScript 3 (Flex/Flash applications)

• Based on the SDMX information model v. 2

11

12

Why SDMX?

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)

13

SDMX framework: Basic organisation

13

Data

SDMX-ML data files(data sets, series, observations, etc)

SDMX-ML data structure definitions (concepts, code lists, data structure definitions, etc)

ECB SDMX Framework

SDMX-ML Readers

SDMX Information model

Visual display

Applications

Application 1

Application 2

Application 3

Application 4

Read

View

Use

Translate

Access

Users

14

SDMX framework in a nutshell

3 layers:

1. The readers: Reads the Data Structure Definitions and the data files (SDMX-ML Compact and Structure formats, v. 2)

2. The model: translation of the extracted data into objects of the SDMX Information Model

3. The views: visualisation of the objects of the SDMX information model (charts, tables, metadata panels, etc)

15

Why open source?

15

• Rapid, robust development• Reduced institutional costs• More thorough code review• Better code support

16

Logistics and License

16

• ECB, NY FED, BOC• Code hosted and publicly available on Google Code• Strict commit policy and change management

procedures• BSD license• Roles

– Leadership roles (Project Manager, Project Advisor and Project Architect)

– Committers: three individuals– Contributors: contributions are welcome from all

– Users: the code is available to all

17

The Plan for 2009

17

• Test code with data from sources other than ECB• Add readers for additional SDMX formats• Remove hard coded concepts• Move style information to its own library• Create high level developer documentation• Improve test coverage

18

ECB inflation dashboard

• Visual display of key ECB statistics

• Analytical dashboard, to support data analysis

• Offers context, history and compare functionalities

• Support interaction (e.g.: data drill-down)

• Customisable

http://www.ecb.europa.eu/stats/prices/hicp/html/

inflation.en.html

19

ECB inflation dashboard

20

Generalisation: ECB website and SDW

• Generalise the use of this technology to other sections

of the ECB website (e.g.: effective exchange rates,

HCIs, Eurosystem joint dissemination sections, etc.)

• Replace charts of the ECB Statistical Data Warehouse

with similar interactive visualisation tools

• Add new statistical domains to the ECB dashboard

21

Links to experiment with…

• Inflation dashboard (test environment):

http://www.ecb.europa.eu/stats/prices/hicp/html/inflation.en.html• Foreign exchange rates:

http://www.ecb.europa.eu/stats/exchange/eurofxref/html/eurofxref-graph-usd.en.html

• Euro area yield curve: http://www.ecb.europa.eu/stats/money/yc/html/index.en.html

• SDMX Browser: http://stats.ecb.europa.eu/stats/dtf_test/browser.html

(test data file: http://stats.ecb.europa.eu/stats/dtf_test/hci.xml)• Flex-CB project: http://flex-cb.googlecode.com/