Point List Duplicate and Gap Checker
Scans survey point lists for duplicate numbers, missing ranges and coincident coordinates.
Paste your point list
First column is the point number, then easting and northing. A header row is detected and skipped. Runs in your browser — nothing is uploaded.
Report
Paste a point list to check it.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Paste your point list with the point number first, then easting and northing.
- A header row is detected and skipped automatically.
- Read the report: duplicate numbers, missing ranges, coincident coordinates and invalid rows.
How it works
The checker reads each row, then cross-checks the set: point numbers that repeat, integer point numbers with gaps in the sequence, and different points sharing the same coordinate within a small tolerance.
Rows with a missing point number or non-numeric easting/northing are listed separately so you can fix the source data before importing.
Worked example
A list with point 2 twice and 3–4 missing. For points 1, 2, 2, 5 the tool flags point 2 as duplicated, reports the missing range 3–4, and notes any two points sharing the same coordinate.
Frequently asked questions
What counts as a coincident coordinate?
Two different point numbers whose easting and northing match within about a millimetre. That usually means a point was recorded twice under different numbers, or a typo.
Why does it skip my first row?
If the first row has non-numeric coordinates it's treated as a header and ignored. Remove the header if your first line is real data.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
- Survey CSV Cleaner
- Coordinate Import Template Generator
- Easting/Northing Distance Calculator
- Point List Renumber Tool
- Coordinate CSV Schema Builder
- Point Code Parser
Explore more in Surveying, Coordinates, GIS & CAD.
Cite this tool
Zerdly. (2026). Point List Duplicate and Gap Checker. Retrieved from https://www.zerdly.com/tools/point-list-duplicate-and-gap-checker/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.