databasedatabase-designgeolocationsqlalchemypylons

Sqlalchemy: Latitude and Longitude Float Precision?

I'm using Sqlalchemy to define my tables and such and here is some code I came up with:

locations = Table('locations', Base.metadata,
Column("lat", Float(Precision=64), primary_key=True),
Column("lng", Float(Precision=64), primary_key=True),
)

I read somewhere that latitude and longitude require better precision than floats, usually double precision. So I set the precision manually to 64, is this sufficient? Overkill? Would this even help for my situation?

Solution

  • It depends on what you are using your data for. If you use a float it will be ok if the you only need it down to about the meter level of detail. Using the data in graphically applications will cause a jitter effect if the user zooms in to far. For more about jitter and see Precisions, Precisions. Hope this helps.