Plot a CSV on a map
MapGeoData plots a CSV of latitude and longitude straight onto a map in your browser. Drop the file in and the points appear, colored by any column you pick. No account, no install, and no tracking cookies.
A spreadsheet is not a map, until it is
Coordinates arrive in spreadsheets constantly: sensor readings, sample sites, store locations, asset registers, survey results, anything exported from a database with a lat and a long column. The data is right there, and seeing it still means either desktop GIS or an account with someone.
MapGeoData plots it directly. Drop the CSV on the map and each row with a usable pair of coordinates becomes a point.
How to map your CSV
- Check you have two coordinate columns. Latitude and longitude in decimal degrees is the common case, and the usual column names are recognized automatically.
- Drop the file onto the map, or use the Add menu. The delimiter is worked out from the file, so comma, tab, and semicolon files all open.
- Color by a column. Pick any numeric column for a continuous ramp, or a text column for categories, and the legend follows.
Every other column comes along as an attribute. Click a point to read its row, or open the data table to sort, filter, and edit.
When the points land in the wrong place
Two things put a CSV somewhere unexpected, and both are common enough to be worth naming.
Latitude and longitude swapped puts your data at right angles to where it should be, usually in an ocean. The fix is to swap the columns, or rename them so the intended pair is obvious.
Projected coordinates are the other. A CSV has nowhere to record a coordinate system, so a file of eastings and northings looks like ordinary numbers, and treating them as degrees puts everything near the middle of the map. MapGeoData spots values outside the lat/long range and offers to assign the right system, with the map as the check: pick a candidate, see where the data lands, keep it if it's right.
What you can do once it's plotted
- Style by column, with ramps, categories, graduated point size, and labels.
- See density by switching to a heatmap or hexbin view, which is what large point sets usually need.
- Filter to a value range, or select rows by expression.
- Measure distance and area.
- Join another CSV of values onto the points by a shared key.
- Export as GeoJSON, a Shapefile ZIP, or FlatGeobuf.
Runs in your browser
Your CSV is parsed and drawn by code running in your browser, so the file never leaves your machine. There's nothing to install and no account to create. It sets no tracking cookies, and we never sell or share your data.