Description
Convert nonnegative pixelArea using squared scaleLength/scalePixels, then divide projectedArea by cosine(obliquityRadians), with angle strictly within ±π/2.
Reptile and amphibian morphometrics use landmarks, measurement paths, image scales, and supplied correction models. A numeric adjustment does not establish anatomy, growth, health, or animal welfare.
Convert nonnegative pixelArea using squared scaleLength/scalePixels, then divide projectedArea by cosine(obliquityRadians), with angle strictly within ±π/2.
When to use this tool
Use Turtle Shell Photo Area Factor when you need one documented animal measurement component.
How to use the tool and how it works
- Enter pixelArea, scaleLength, scalePixels, obliquityRadians. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read projectedArea, correctedArea. Use the output convention below.
Convert nonnegative pixelArea using squared scaleLength/scalePixels, then divide projectedArea by cosine(obliquityRadians), with angle strictly within ±π/2.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| pixelArea | Pixel Area | Required. Finite number; minimum 0. |
| scaleLength | Scale Length | Required. Finite number; strictly above 0. |
| scalePixels | Scale Pixels | Required. Finite number; strictly above 0. |
| obliquityRadians | Obliquity Radians | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| projectedArea | Projected Area | Required. Finite number. |
| correctedArea | Corrected Area | Required. Finite number. |
{
"input": {
"pixelArea": 10000,
"scaleLength": 10,
"scalePixels": 100,
"obliquityRadians": 0
},
"output": {
"projectedArea": 100.00000000000001,
"correctedArea": 100.00000000000001
}
}Limitations and assumptions
- The angle is tilt from a face-on planar view; a curved shell, lens distortion, perspective variation, and actual animal size require separate modeling.
- 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
Check measurement conventions, species-specific evidence, uncertainty, and appropriate animal-care expertise before biological or welfare decisions.
References
Similar or alternative tools
- Turtle Carapace Straight Curved Ratio
Return curved/straight, their absolute and relative excess, and uncertainty/straight.
- Slide Scanner Microns Per Pixel Factor
Multiply positive baseMicronsPerPixel by positive downsample for levelMicronsPerPixel, then by nonnegative pixels for lengthMicrons.