[Mehulsri07]

A City map tab: the model painted over the whole city, in three modes.

• Ground at a depth: a depth slider (5 ft steps); colour is the likeliest kind of ground there.
• Depth to water-bearing sand: how deep the first water-bearing sand at least 10 ft thick is likely to be, light where shallow, dark where deep.
• Where data is thin: how sure the proposals are at the chosen depth, on their own, so gaps in the records stand out.

In every mode the colour is strong where likely, pale where a rough guess, and clear where there is not enough data. Each mode has its key, and the panel says how big each square is and that these are proposals, not measurements.

How: about 10,000 square cells over the borewells plus 2 km, kept within the ground-height data. They are worked out a few at a time after the tab is first opened, with progress shown, so the screen stays responsive (a few seconds for 500 borewells). The picture lies under the borewell pins. No new libraries.

Checks: 141 unit tests (codes and levels per step, the first water-bearing sand ≥ 10 ft, unknown ground, area margin, staying within the ground data, square cells, painting per mode); the real-app test opens the City map; screenshots of all three modes checked.

Review fixes: "Working out the map…" forever with nothing to map; the map hid the borewell pins; one far-off borewell stretched the map over 100 km; cells were not square; the slider before the map was ready; the mode choice is now real radio buttons; "300+" on the water-bearing key.