How Many Decimal Places Should You Use for Latitude and Longitude to Achieve 50 Feet Accuracy?

How Precisely Should You Store Latitude and Longitude:

The precision of latitude and longitude storage depends on the desired accuracy of location representation. To determine the appropriate storage format, consider the following factors:

Accuracy Requirements:

You aim to maintain an accuracy of within 50 feet from the actual location.

Decimal Point Impact:

Each decimal point increases precision by one order of magnitude. For example:

• 0 decimal places: accuracy of approximately 6000 miles
• 1 decimal place: accuracy of approximately 600 miles
• 2 decimal places: accuracy of approximately 60 miles
• 3 decimal places: accuracy of approximately 6 miles
• 4 decimal places: accuracy of approximately 0.6 miles

Equation to Calculate Decimal Places:

To determine the number of decimal places needed for a specific accuracy, use the following equation:

Decimal Places = log10(Accuracy in meters / 0.0000111)

Calculating for 50 Feet Accuracy:

Given an accuracy requirement of 50 feet, the equation becomes:

Decimal Places = log10(15.24 / 0.0000111) = 4.15

This value indicates that you need approximately 4 decimal places to store the latitude and longitude with an accuracy of within 50 feet.

Recommendation:

For most applications where accuracy within a few meters is sufficient, storing latitude and longitude with 3-4 decimal places is a good balance between precision and storage efficiency. This level of precision corresponds to an accuracy of approximately 1.11 meters (3.67 feet).

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