In DataPicta, you can visualize data on a wide range of predefined geographic regions, such as continents, countries, states, and provinces. However, there may be instances where you want to create your own custom geographic region or modify an existing one to better suit your data visualization needs. In this tutorial, we will guide you through the process of adding the 'Ijsselmeer' lake to the Netherlands region.

Start with the Netherlands

• Open the DataPicta app by going to app.datapicta.com (this will open a separate browser tab).
• If you have used DataPicta before, click on 'New blank chart' in the menu in the top right corner.
• Click on the plus icon (+) next to 'Data'.
• In the 'Add data' dialog, click 'Use geographic data'.
• Choose 'Countries' as the preset.
• Now search for 'Netherlands' in the list of countries and select it.

The Netherlands is a country in Western Europe, but it also has several overseas territories in the Caribbean. DataPicta includes these territories when you select the Netherlands. Let's fix that by removing these overseas territories.

Remove overseas territories

• In the geographic data table, click on the trash can icon next to 'Saba' and delete this island from the data table.
• Do the same for 'Sint Eustatius'.
• Above the data table, there is an icon to switch to the chart view, click it

You should now have a chart showing data for the Netherlands only.

Add the Ijsselmeer lake

If you are familiar with the geography of the Netherlands, you may notice that the Ijsselmeer lake is missing from the map. The Ijsselmeer is a large freshwater lake in the central Netherlands, and it is an important geographic feature of the country. Let's add it to our map.

• With the geographic data table still open, you see an icon of the earth, click it to open the geojson.io website with the current geographic data.
• On the geojson.io website, you can see the map of the Netherlands. Now we need to add the Ijsselmeer lake to this map.
• We do this by 'shrinking' the land area of the lake to create a hole in the map.
• Click on the icon with the pencil in the toolbar on the right side of the screen to enter edit mode.
• Start by dragging the corners of the 'Noord Holland' province to create some space for the lake.
• Do the same for the 'Flevoland' province.
• Finally, adjust the corners of the 'Friesland' province to create more space for the lake.
• Now that we are done we can save the modified geographic data, click on the 'Save' button in the top right corner of the screen.
• Choose 'GeoJSON' as the format and save the file to your computer.
• Go back to the DataPicta app and click on the plus icon (+) next to 'Data' again.
• Start with a new blank chart by clicking on 'New blank chart' in the menu in the top right corner.
• Click on the plus icon (+) next to 'Data'.
• In the 'Add data' dialog, click 'Use geographic data'.
• This time, instead of choosing a preset, click on 'Upload a GeoJSON file' and upload the modified GeoJSON file that you just saved.
• After uploading, you will see the modified map with the Ijsselmeer lake included.