OneTaskBy Tim King · Updated
Bubble Map Maker
Paste Latitude, Longitude and Value Rows, Export Sized Circles as SVG or PNG
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the Bubble Map Maker works
This bubble map maker sizes a circle at each place. A bubble map, or proportional symbol map, puts a circle at each location with its area scaled to a value, so city populations, store sales, earthquake magnitudes or sensor readings can be compared by place without the area bias of a choropleth. Paste rows of latitude, longitude and a number, and download the result as SVG or PNG. Nothing is uploaded.
Bubble map maker: what to paste
One row per point with a latitude, a longitude and a value, plus an optional name, separated by commas or tabs. A header row is optional; when present, columns whose names start with lat and lng, lon or long are used for coordinates, the first remaining numeric column is the value, and the first text column is the name. Without a header the first two numeric columns are taken as latitude then longitude and the third as the value. Latitude runs from -90 to 90 and longitude from -180 to 180, decimal degrees, south and west negative; rows outside those ranges or missing a coordinate are dropped. Points with no value are drawn at the smallest size.
Sizing
Circle area, not radius, is proportional to the value, so a bubble for 4 million is twice the width of one for 1 million, not four times, which is how readers judge circles by eye. The Bubble size setting sets the largest circle to 3, 5 or 8 percent of the map's shorter side; pick Small when many points cluster and Large for a sparse set. Bubbles are drawn largest first so small ones are never hidden underneath, and they are semi-transparent so overlaps show as darker patches. Negative values are sized by their magnitude.
Map extent
Fit to points centres the map on your data and zooms an equal-area azimuthal projection to fit, which gives a proper regional map for a country or continent without any settings. When the points span most of the globe the fit falls back to the whole world. World always shows the full Natural Earth projection with graticule. Country outlines are drawn in grey beneath the bubbles for orientation; they are not matched or coloured.
Labels and legend
Largest 10 names the ten biggest bubbles, which keeps the map readable; All labels every point and None removes them. The legend at the bottom-left shows circles for the maximum value and a quarter of it, and takes its title from the value column's header unless you set one. Hover any bubble for its name, value and coordinates.
Reading the stats
Points counts the rows drawn and how many fell outside the visible map. Largest and Smallest name the extremes. Total sums the values, and Centre gives the geographic centre of the points as latitude, longitude.
Exporting
Download SVG gives a vector file with one circle per point and editable labels. Download PNG renders at one, two or three times the preview width. Copy SVG puts the markup on the clipboard.
FAQ
Where do I get latitude and longitude for my places?
Most spreadsheet map add-ons, postcode lookup services and any online map will give decimal coordinates; right-clicking a location in most web maps shows them. Paste them as decimal degrees, not degrees-minutes-seconds. Use negative numbers for the southern and western hemispheres rather than S and W suffixes.
Why is my point in the ocean?
Almost always the latitude and longitude are swapped. Name the columns lat and lng so the tool picks them by name, or make sure latitude comes first in a headerless paste. A longitude with the wrong sign puts a point on the other side of the world at the same latitude.
Can I colour bubbles by category?
Not in this tool; all bubbles use the first colour of the chosen palette. For coloured groups on a plain x, y grid use the bubble chart maker, or export the SVG and recolour circles in a vector editor, where each circle carries its name as a title.
How is the Fit to points map projected?
With a Lambert azimuthal equal-area projection centred on the geographic centre of the points, so areas are true and distances from the centre are not badly distorted. It is the same family of projection national statistics agencies use for continental maps.
See also: all Chart Makers tools, Images, Audio, Video & Screen, PDF, SVG, Simulations & Screensavers, Generative Art, 3D Model Viewers, Drawing Pads, Mockups & 3D Making, Diagram Makers, 3D Science, Tracker Music.
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