Coordinate Validator
Validate GPS coordinates and check for common errors before your geocaching adventure.
What is a Coordinate Validator?
A coordinate validator checks GPS coordinates for errors before you head out geocaching. It verifies that latitude and longitude values are within valid ranges, detects the coordinate format, and warns about potential issues like swapped values or coordinates pointing to water.
This tool is essential for puzzle cache solvers who need to verify their calculated coordinates are valid before making a trip to ground zero.
Why Validate Coordinates?
Invalid or incorrect coordinates can lead to wasted trips, frustration, and safety issues. Common problems this validator catches include:
- Out of range values: Latitude must be -90° to 90°, longitude -180° to 180°
- Swapped coordinates: Lat/lng accidentally reversed
- Typos: Missing digits or decimal points
- Format errors: Mixed formats or incorrect separators
- Water coordinates: Points in oceans or lakes
Valid Coordinate Ranges
GPS coordinates use the WGS84 datum (World Geodetic System 1984), the standard for GPS navigation. Valid ranges are:
- Latitude: -90° (South Pole) to +90° (North Pole)
- Longitude: -180° (West) to +180° (East)
The equator is 0° latitude, and the Prime Meridian (through Greenwich, England) is 0° longitude. Positive latitude values indicate North, negative values indicate South. Positive longitude values indicate East, negative values indicate West.
Common Coordinate Mistakes in Geocaching
Swapped Latitude and Longitude
One of the most common errors is accidentally swapping latitude and longitude. If your latitude value is greater than 90° (or less than -90°), the coordinates are definitely swapped.
Example: -122.4194, 37.7749 should be 37.7749, -122.4194
Missing Negative Signs
For locations in the Western Hemisphere (Americas) or Southern Hemisphere (Australia, South America), longitude or latitude values should be negative. Forgetting the negative sign can place you on the wrong continent.
Example: San Francisco is at 37.7749, -122.4194, not 37.7749, 122.4194(which would be in China).
Decimal Point Errors
In puzzle caches, calculated values sometimes have decimal points in the wrong place. The validator helps identify when coordinates seem implausible.
Minutes Greater Than 60
In DDM and DMS formats, minutes must be between 0 and 59.999. A value like "N 51° 72.5'" is invalid because 72 minutes is impossible.
Geocaching Coordinate Best Practices
- Always verify: Check coordinates on a map before heading out
- Use the right format: Geocaching.com uses DDM (N DD° MM.MMM')
- Double-check puzzle solutions: One digit error can be miles off
- Consider context: Does the location make sense for a geocache?
- Check terrain: Is the location accessible and reasonable?
Coordinate Precision for Geocaching
Standard geocaching coordinates use 3 decimal places in the minutes value (DDM format), providing accuracy of approximately 2 meters. This is sufficient for finding a geocache.
- 0.001' (minute) ≈ 1.85 meters accuracy
- 0.01' (minute) ≈ 18.5 meters accuracy
- 0.1' (minute) ≈ 185 meters accuracy
If your puzzle solution gives more than 5 decimal places, the extra precision is likely noise from calculations. Round to 3 decimal places for practical use.