Improvement "Geodata Classification"

[Alec-SE]

The text and content regarding the classification with the purpose of styling a layer are good. However, the topic of data classification and interval selection is not represented. Here are some resources you can check out about this very important topic:

• Choropleth Maps – A Guide to Data Classification
• The Basics of Data Classification
• Data Classification
• DATA CLASSIFICATION METHODS
• Lec 6.4 Data classification](https://www.youtube.com/watch?v=Xcksq9YVu7g)

Besides that here are some more points:

• [x] Use headers to make the navigation easier. Here is how to use headers. Add, headers between sections.
• [x] Add videos
• [x] Add an example of the same dataset classified based on different intervals