GIS Storage Precision BC Environment GIS Storage Precision See Scale, Accuracy, and Resolution in a GIS for a general discussion of related topics.
Double precision requires twice the storage space, but carries more accuracy.
Typically, double precision preserves about 14 decimal digits, while single precision preserves about 7. For example, the '.32' in the number '5,523,470.32' is lost when it is stored in single precision. The '4.78' in the number '8,452,984.78' is lost when it is stored in single precision. Long integers store numbers from -2,147,483,648 to 2,147,483,647 preserving 9 decimal digits of precision. Therefore, UTM or Albers coordinates for all of BC can be stored in metres or even centimetres in these systems.