Geodetic to Plane Scale Factor Point Check
Compare observed local projected/ground distance ratio with independently established point scale factor; no projection model or geodetic correction.
Description
Flag a map-to-ground distance ratio outside the tolerance of a supplied point scale factor.
A point scale-factor screen compares the ratio of map distance to ground distance with a supplied reference factor. Both distances must use the same units.
When to use this tool
Flag a map-to-ground distance ratio outside the tolerance of a supplied point scale factor. Use it when the input measurements and conventions below match the operation you need.
- Prepare mapDistanceM, groundDistanceM, callerScaleFactor, callerTolerance, respecting the measurement basis and boundaries below.
- Compare the worked example with your intended operation before reusing its result.
How to use the tool and how it works
- Enter every field in the input table using the stated units and exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
The tool requires positive map distance, ground distance and caller scale factor, plus nonnegative tolerance. It computes mapDistance divided by groundDistance and flags an absolute difference from the caller factor that exceeds tolerance.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| mapDistanceM | Map distance m. Meters. | Finite number; greater than zero |
| groundDistanceM | Ground distance m. Meters. | Finite number; greater than zero |
| callerScaleFactor | Caller scale factor. | Finite number; greater than zero |
| callerTolerance | Caller tolerance. | Finite number; zero or greater |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.callerReviewFlag | Caller review flag flag under the exact conditions described above. |
{
"input": {
"mapDistanceM": 100,
"groundDistanceM": 100,
"callerScaleFactor": 1,
"callerTolerance": 0.01
},
"output": {
"result": {
"callerReviewFlag": false
}
}
}Limitations and assumptions
- The tolerance applies to the dimensionless ratio. No projection parameters, height correction or geodetic scale factor are independently derived.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
For a map-layout decision, inspect the rendered map at its intended size as well as its numerical dimensions. For classification or coordinate work, retain the chosen boundary and coordinate conventions with the result. Compare the scope of the nearby tools below before substituting one.
References
Similar or alternative tools
- Best Fit Scale for Paper Size Finder
Minimum continuous denominator fitting projected extent to actual usable print dimensions, fixed orientation; no standard-scale rounding.
- enlargement new scale
New 1:N scale denominator after enlarging a map by a linear factor greater than zero.