This question already has an answer here:
I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and its services like the Geocoder. I'm working with data in America and the main calculations are for nearest neighbors. Results will be plotted back on a web map (eg: via Google maps API or leaflet)
Question: What spatial reference system is Google map using? I figured out so far that its the WGS 84 datum with the Mercator projection in the geographic coordinate system. Should I store the location data as it is, or transform to US National Atlas Equal Area EPSG:2163?
Since I will be calculating distances and finding nearest neighbors, if I guess correctly that doing nearest neighbor search requires transforming the entire table to EPSG:2163, then will the solution be to store the data in both Mercator and EPGS:2163?