How create a new array field with the aggregate framework

Question

I\'m starting to use mongoDb and I\'m stuck with a simple use case.

Let\'s say I\'ve got a collection \'aCollection\' with entries such as this:

Answer 1

Ok, so first of all let us understand what aggregation framework does. It only queries the available data and returns the result. It does NOT modify the original documents! That is why the second piece of code that you have written performs an aggregation, does a projection and displays some result of a successful run of an aggregate query.

To make the changes that you are trying to do, you can either try the 'quick and dirty' approach of Martin Konecny's answer or you can modify the code for uploading the data and perform a fresh upload.

Since I see that instead of using decimal point you are using comma in the lat/long values I would say that if later on in time you will try to query this geo-spatial data, you better upload it again properly.