How to use the lat/long map plotter

Display format and markers persist in localStorage. Place search and reverse geocoding call Nominatim (OpenStreetMap) over the network; manual/CSV modes are offline.

Workflow

1. Single point: search an address (Nominatim), type decimal/DMS coordinates, or click the map to drop a pin. Step 1 completes the workflow described on the homepage; repeat or adjust inputs before the next action.
2. Bulk: paste or upload a CSV/TSV with lat/lng columns (auto-detected headers) or one lat,lng per line, then Plot all. Step 2 completes the workflow described on the homepage; repeat or adjust inputs before the next action.
3. Click a marker for address (when reverse-geocoded), decimal + DMS values, and Copy coordinates. Step 3 completes the workflow described on the homepage; repeat or adjust inputs before the next action.
4. Pick two markers in Options to see haversine distance in miles or kilometers. Step 4 completes the workflow described on the homepage; repeat or adjust inputs before the next action.
5. Download CSV or Copy shareable link (lz-string URL hash) so others see the same pins with no server storage. Step 5 completes the workflow described on the homepage; repeat or adjust inputs before the next action.

Worked examples

• Spreadsheet review: Paste latitude and longitude columns to inspect a set of field locations. Use the primary control (Add a point) after setting options appropriate to this scenario.
• Coordinate check: Enter DMS coordinates and compare the plotted marker with a known point. Use the primary control (Add a point) after setting options appropriate to this scenario.

Before you roll

Lat/Long Map Plotter is for checking coordinates, visualizing a small dataset, or comparing points without a paid map account. Add a point by searching, typing decimal or DMS coordinates, clicking the map, or importing a CSV; then inspect markers, measure between two, and export

Confirm everyone agrees what Add a point means for your group before you rely on a single outcome.

Open Options or the sidebar when labels are hidden on small screens.

If something looks wrong

If results look wrong: Map tiles and geocoding depend on third-party services; straight-line distance is not driving distance.

Mobile and keyboard notes

Add a point is reachable from touch and keyboard.

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