Description
Return marker displacement and average migration speed.
Microscopy coordinates require scale, origin, orientation and often optical correction. A normalized landmark coordinate or refractive-index ratio is one geometric term rather than a complete image registration or validated biological measurement.
Return marker displacement and average migration speed.
When to use this tool
Use Gastrulation Marker Migration One Step when checking a supplied developmental-image coordinate transformation.
How to use the tool and how it works
- Enter startX, startY, endX, endY, elapsed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read dx, dy, speed. Use the output convention below.
Return marker displacement and average migration speed. Require elapsed > 0; dx,dy subtract initial from final coordinates, and speed = hypot(dx,dy)/elapsed.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| startX | Start X | Required. Finite number. |
| startY | Start Y | Required. Finite number. |
| endX | End X | Required. Finite number. |
| endY | End Y | Required. Finite number. |
| elapsed | Elapsed | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| dx | Dx | Required. Finite number. |
| dy | Dy | Required. Finite number. |
| speed | Speed | Required. Finite number. |
{
"input": {
"startX": 1,
"startY": 2,
"endX": 4,
"endY": 6,
"elapsed": 2
},
"output": {
"dx": 3,
"dy": 4,
"speed": 2.5
}
}Limitations and assumptions
- Use calibrated length/time units; this chord speed does not recover a curved trajectory or mechanism.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use calibrated imaging and suitable full shape or optical models when geometry and measurement accuracy matter.
References
Similar or alternative tools
- Embryo Landmark Procrustes One Coordinate Gap
Compare one centered, scaled landmark coordinate.
- Embryo Image Zdepth Refractive Factor
Apply a supplied refractive-index depth scaling.