What you see
Marks near your job show up as small triangles, colored by their last recovery report:
- Green: recovered in good condition recently.
- Amber: reported in poor condition, or not visited in a long time.
- Hidden: marks reported destroyed, so they don't waste your morning.
Tap a triangle for the details: what the disk is, what's stamped on it, what it's set in, its condition and last recovery date, its elevation, and on request the written directions to reach it from whoever set or last recovered it.
The published coordinate, in your job
The card shows the mark's published NAD 83(2011) State Plane coordinate, converted into your job's grid. Create a point from it and that published value goes into your job, untouched by phone GPS. Then you can export it, stake to it, or tie your traverse to it.
That ties your work to the National Spatial Reference System through a disk that may be half a mile from the job.
Works in a dead zone
Marks are fetched once for the area while you have a data signal and stored with the job. After that, they're there with no signal at all.
The official datasheet from NGS remains the authority. Check it before relying on a mark for control, and if you visit one, consider filing a recovery report with NGS so the next crew knows its condition.
How to see the marks near a job
- Open the app and start a job with GPS Start, which puts it on State Plane coordinates with imagery behind it.
- With a data signal, zoom the imagery to your area. The triangles load on their own.
- Tap a triangle to read the card, then Create point & navigate to walk to it.
Questions
How do I find survey benchmarks near me?
NGS publishes its marks online. ChainLink Survey shows the ones around your job on aerial imagery, colored by condition, with directions to each one. Start a job with GPS Start and they appear once you have a data signal.
What is the difference between a benchmark and a horizontal control mark?
A benchmark has a published elevation. A horizontal control mark has a published horizontal position. Many NGS marks carry both, and the card shows what has been published for each one.
Is the coordinate the official NGS value?
It is the published NAD 83(2011) State Plane value converted to your job's grid. For control work, confirm it against the official NGS datasheet.