Background

The pages in this section explain why a gauge's reading is unusable until its sensor has been surveyed, and what a satellite could change, for a reader who has not spent time around tide gauges or vertical datums, drawing on what the people who run Maine's gauge network have published about it.

The Unsurveyed Gauge starts from why a coastal flood forecast reaches so few Maine towns, explains what a low-cost gauge measures and what its survey supplies, and ends on what a satellite could change.

Once the problem is clear, Data says where each kind of data the comparison reads comes from.