- A concise explanation of the problem you are experiencing.
How could I create a polygon?
- An example of a minimum code. If you have found an error, this helps us to reproduce and repair it.
I’ve only seen code already with a rectangle
- Context. Why do you need to do this? We could know a better way to achieve your goal.
to mark areas of interest
- The version of Cesium you are using, your operating system and browser.
Check out this Sandcastle example which shows how to draw lines and polygons. Saving the data to a database is beyond the scope of this group.
Are you sure you’re using Cesium 1.4? That build is from many years ago. Cesium has monthly releases. The current version, 1.55, is very, very different.