Resection Calculator

Determine the coordinates of an unknown point by measuring angles from known reference points

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Known Point A

Known Point B

Known Point C

Angle Measurements

Resection Results

Unknown Point Coordinates:
Distance to Point A:
Distance to Point B:
Distance to Point C:
Internal Angle Check:

Frequently Asked Questions

What is resection in surveying?

Resection is a method for determining an unknown position (point P) by measuring angles to at least three known points. It’s commonly used in surveying when you need to establish your position based on visible landmarks or control points.

How many known points do I need for resection?

You need a minimum of three known points to perform a resection calculation. However, using more points can improve accuracy and provide redundancy to check your results.

What coordinate system should I use?

This calculator works with any consistent coordinate system. You can use local grid coordinates, state plane coordinates, or UTM coordinates as long as all points use the same system.

What if I get an error in my calculation?

Errors can occur if your known points are colinear (in a straight line) or if your angle measurements are inconsistent. Double-check your input values and ensure your known points form a good geometric configuration.

Can I use this for GPS coordinates?

Yes, but you’ll need to convert latitude/longitude to a projected coordinate system (like UTM) first, as angular calculations require Cartesian coordinates.