How numbers change – over time and space

What to do if the data on the maps is constantly changing? You can also visualise the changes! For example: Where are the countries whose population has not increased in recent years? This question can be answered graphically using maps.

Open the following page:

https://www.arcgis.com/apps/mapviewer/index.html?webmap=f5e6469be6c34f2194758b7af02109f3

On the right-hand side you will find the ‘Styles’ menu:

The expression ‘pop2015’ can be deleted here (by clicking on the x symbol). A new expression is then selected for display. To do this, click on the ‘+ Expression’ button. A window opens that reminds us of a code editor:

On the right-hand side we find the menu item for inserting variables:

Here we enter the expression to determine the change in population (2010 vs. 2015):

Finally, we need to improve the display. To do this, we will again use the menu items on the right-hand side:

Pick a style:

Color and Size

Theme:

Above and below

Symbol pair:

Circles with arrows

We can now easily identify those countries on the map where the population fell between 2010 and 2015: