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ENU Local Tangent Plane Component Converter

Rotate an ECEF displacement vector into ellipsoidal East/North/Up at an explicit origin latitude/longitude; input is a delta, not an absolute position or a datum transformation.

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Description

Rotate an ECEF displacement into local east, north and up at a supplied origin direction.

Geodesy distinguishes a mathematical reference ellipsoid, a realized coordinate datum and the physical gravity field. Geodetic latitude follows the ellipsoid normal; geocentric latitude follows a radius from the center. Ellipsoidal height, orthometric height and geoid undulation are separate signed quantities. Keep the declared ellipsoid, coordinate axes, angular units and time scale with a result.

Rotate an ECEF displacement into local east, north and up at a supplied origin direction.

When to use this tool

Use this tool when you need to rotate an ECEF displacement into local east, north and up at a supplied origin direction.

How to use the tool and how it works

  1. Enter latitudeDegrees, longitudeDegrees, ecefDeltaMeters using the definitions below.
  2. Run the operation. Resolve input-format errors before interpreting an output.
  3. Read result.enuMeters, using the stated boundary, ordering, sign and absence conventions.

Rotate the supplied ECEF displacement [dX,dY,dZ] into local east, north and up at the given geodetic latitude/longitude, using the orthonormal tangent-frame matrix.1

Input fieldMeaning and unitsAccepted input
latitudeDegreesGeodetic latitude in degrees, north positive; the operation’s pole restrictions apply.Finite numeric value satisfying the stated comparisons.
longitudeDegreesEast-positive longitude in degrees from −180 through 180.Finite numeric value satisfying the stated comparisons.
ecefDeltaMetersThree Cartesian displacement components [dX,dY,dZ] in meters, each magnitude≤10⁹.Dense list of at most 128 finite numbers, under the stated integer/range rules.
Output fieldInterpretation
resultObject containing the fields below.
result.enuMetersRotated displacement [east,north,up] in meters.
json
{
  "input": {
    "latitudeDegrees": 0,
    "longitudeDegrees": 0,
    "ecefDeltaMeters": [
      1,
      2,
      3
    ]
  },
  "output": {
    "result": {
      "enuMeters": [
        2,
        3,
        1
      ]
    }
  }
}

Limitations and assumptions

  • The vector is already a displacement in meters, with three entries within ±10⁹. Absolute ECEF positions require subtracting an origin first; the tool performs no origin translation or geodetic datum conversion.
  • All quantities are finite and retain the units stated for this operation. Ellipsoid-parameter tools use semi-major axis 1–10⁸ m and dimensionless flattening 0–0.02; explicit-axis tools use 0.9a≤b≤a unless a tighter bound is stated. These tools do not fetch datums, geoid grids, satellite observations or Earth-orientation updates.
  • Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
  • Numeric results must be finite. Large physical magnitudes are allowed by the output evidence checks, while integer fields and source schemas retain their exactness rules. Source indexes are zero-based. Floating-point residues can remain even where an ideal formula gives an exact zero.

Alternative or Complementary methods

Use a coordinate transform for a change of representation and explicit datum parameters for a change of reference frame. Preserve model and convergence metadata, and use observation and datum information appropriate to a real survey before interpreting a computed tolerance as accuracy.

References

  1. Tool behavior and example: ENU Local Tangent Plane Component Converter — tool.io

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