Isarithm Interval Round Number Picker
Round a positive raw isarithm interval upward to 1/2/5 times a decade; no automatic scientifically suitable contour interval.
Description
Round a positive proposed contour interval upward through the 1, 2, 5 decimal series.
A contour interval is easier to read when its numerical step has a simple decimal form. This picker rounds a proposed positive interval upward to a value from a fixed decimal series.
When to use this tool
Round a positive proposed contour interval upward through the 1, 2, 5 decimal series. Use it when the input measurements and conventions below match the operation you need.
- Prepare rawInterval, 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 finds the interval's power-of-ten decade and chooses the first adequate multiplier from 1, 2, 5 and 10. The returned roundedInterval is therefore at least the supplied rawInterval, subject to ordinary floating-point arithmetic.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| rawInterval | Raw interval. | Finite number; greater than zero |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.roundedInterval | Rounded interval; use the stated units and sign convention. |
{
"input": {
"rawInterval": 3
},
"output": {
"result": {
"roundedInterval": 5
}
}
}Limitations and assumptions
- This is a numerical rounding convention, without terrain, depth, accuracy or map-scale analysis. Extremely small values whose decade underflows are rejected rather than assigned a misleading interval.
- 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
- Bathymetric Depth Contour Interval Selector
Qualified caller-reference registry: actual survey depth range, scale, charting standard and independently reviewed contour interval. Requires independently applicable source/context/date evidence; not an authoritative table, omitted predictive model, diagnosis, permission, safety or compliance determination.
- Contour Interval Selection by Relief Lookup
Qualified caller-reference registry: actual relief, scale, intended map use and independently reviewed contour-interval specification. Requires independently applicable source/context/date evidence; not an authoritative table, omitted predictive model, diagnosis, permission, safety or compliance determination.