I am interested in understanding and applying practical geo-spatial examples for some of the transportation data that I have. I have several geocodes that I will pull from the database, and display in maps - as map clusters and points, similar to Redfin.
I want to unlock more value of my data - for instance allow the user to draw a ploygon and compute the number of points inside the polygon. Click on 2 markers and display distance etc. This makes the map more feature rich as opposed to a simple cluster of markers.
I like what leaflet offers and the abilities in Postgres/PostGIS to issue geospatial queries, and I am looking to build UI where users can query in a more intuitive mouse click and drag operations. Please point me to some good examples or sites that have implemented this.