Territory > The municipality in figures > Google Public Data Explorer: questions and answers

Google Public Data Explorer: questions and answers

Google Public Data Explorer

To facilitate the exploration of the information in The municipality in figures, Idescat has created a Catalan municipalities indicators dataset on the Google Public Data Explorer platform. Considering the strength, flexibility and complexity of this data visualisation tool, there is probably a need for a guide to help users to take full advantage of its functionality, and also to avoid the most frequent problems. The following is a presentation of solutions for common problems and examples of the charts that this tool can be used to generate.

1. How to access data on Catalonia using Google Public Data Explorer

On Google Public Data Explorer you can find datasets available from different institutions in the directory: including Idescat’s Catalan municipalities indicators.

2. How information is organised in Google Public Data Explorer

The Google Public Data Explorer shows metrics (farms, fleet of vehicles, Gross disposable household income…) and dimensions (age group, asset type, birth place…). If you select a dimension, such as "sex", you will see all of the metrics broken down by sex. If you choose a metric, such as "registered unemployment", you must select a municipality (Location) and can show the evolution in that municipality of registered unemployment by sex (line chart) or the distribution of its components (bar chart).

If rather than starting by selecting a dimension, you select a metric, such as "population", you can represent its municipal (bar chart) or spatial (map chart) distribution, its relation with another metric (scatter plot) or its evolution in your chosen municipalities (line chart). You can also filter the chosen metric by a category (for example, "women") of a dimension ("sex") and represent the same charts for a filtered metric ("female population").

3. How to display a chart when the browser shows a warning

Catalonia has more than 900 municipalities: sometimes, the representation of such a large amount of information can temporarily collapse the browser. In the case of Internet Explorer, you may receive a warning asking you whether you want to stop the execution of the charts’ script. If you stop it, the chart will never be generated. Always answer that you do not want to stop the execution of the script.

4. How to use Google Public Data Explorer charts on your website

If you would like to refer to a chart in Google Public Data Explorer (in your blog, in an e-mail, in a tweet…), use the Link tool that’s at the top of all charts: you will obtain the address (http://www.google.com/publicdata/…), and also the embeddable HTML code (<iframe…), which you can use to insert the chart in your website. In the code, adapt the height and width attributes according to your needs.

5. How to change the language of the chart if it is not in your chosen language

The Idescat information in the Google Public Data Explorer is available in three languages: Catalan, Spanish and English. If the language is not expressly specified, the Google platform will try to deduce the preferred language: for this reason, the information might appear in a different language to the one you want. You can use the following form to obtain the version in a different language of a link or an embeddable code.

6. How to let your users modify a chart without leaving your webpage

You can embed a Google Public Data Explorer chart in your webpage, but you can also embed this visualisation tool with its full functionality: users will be able to modify an embedded chart in your webpage without leaving it, or even generate a completely new one. Remember that embedding Google Public Data Explorer with its full functionality will take up more space on your webpage: properly adjust the height and width attributes.

7. How to monitor the trend over time of a variable in various municipalities or counties

Line charts can be used to represent the trend over time of a variable for different municipalities. First select the metric (for example, "registered unemployment") and the type of chart (lines) and finally the geographical areas you would like to show.

For example: registered unemployment in the municipalities of the Alta Ribagorça county.

8. How to compare the trend over time of the categories of a variable in a municipality or county

Line charts can be used to compare the trend over time of the categories of a variable in a municipality or county. First select a dimension (for example, "place of birth") and then the metric (for example, "population"). Finally, select the geographical area (Location).

For example, population of a municipality by place of birth.

9. How to display changes over time in the structure of a variable in a municipality or county

Bar charts can be used to represent, for a municipality or county, the value of the categories of a variable (height of the bars) and view an animation over time. Remember that bars are shown ordered by value. You can also compare the trend of another variable (colour of the bar).

For example, structure by ages of the population in a municipality and the weight of women.

10. How to analyse the distribution of a variable among Catalan counties or municipalities

Bar charts show municipalities (or counties) ordered in accordance with the value of a variable and make it possible to observe the trends over time of this order (animation), highlighting, if desired, a municipality (or county).

For example: municipal distribution of the IRPF taxable base by declarer.

11. How to explore whether the municipal distribution of a variable is related with another variable

Bar chart can show municipalities or counties ordered in accordance with the value of a variable (height of the bars). The colour of the bar can be used to represent the value of a second variable.

For example: distribution of GDP per capita and the weight of the industrial sector on GVA.

12. How to represent the distribution of two variables in space

Maps can display the distribution of two variables (diameter and colour of bubbles) in space, and can also show the trends of this distribution over time (animation).

For example: map of the population born abroad (absolute and relative value).

13. How to discover relations between different variables

Scatter plots make it possible to show evidence for relations between up to four variables (axis of abscissas, axis of ordinates, diameter of bubble, colour of bubble) over time (animation).

For example, population by place of birth and nationality in the municipalities of Catalonia.

14. How to show different models of change over time

Scatter plots can display different trajectories of change over time (routes) of four variables (axis of abscissas, axis of ordinates, diameter of bubble, colour of bubble).

For example: hotels and hotel spaces in a selection of municipalities in Catalonia.

15. How to represent variables that have a very broad range of values

When the absolute magnitudes of some variables are represented, the diversity in size of Catalan municipalities can make it hard to clearly view the relation between them. One way of reducing the range of values of the original variables consists of expressing them on a logarithmic scale. By default, the charts are shown using a linear scale. You can change the scale on a line chart, bar chart or scatter plot that you made by selecting one of the metrics represented (for example, number of contributors to the General Social Security Regime) and choosing the Scale option.

For example: number of contributors to the General Social Security Regime and registered unemployment, both on logarithmic scale.

16. How to visualise your data in the Google Public Data Explorer

Anyone can upload their datasets onto Google Public Data Explorer. To do so, it must be previously authenticated with a Google account (for example, Gmail) and using the My Datasets option in Google Public Data Explorer.

The datasets have to be formatted in accordance with the Dataset Publishing Language (DSPL) standard. A DSPL dataset consists of a compressed ZIP format package that contains an XML document and different files in CSV format. Remember that DSPL is a standard in development and is gradually incorporating new functionality.

If you want to see an example, you can download Idescat’s DSPL format dataset for the Catalan municipalities indicators (5 Mb). This dataset does not necessarily contain up-to-date statistics nor does it reflect the information that Idescat currently has available on Google Public Data Explorer and is only offered as a sample of a DSPL dataset. Remember that some statistical series are updated retrospectively when more information becomes available: a non-updated dataset may contain not only shorter series, but also historical values that are no longer correct.

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12.12.2014