About MobGIS
What MobGIS is
MobGIS is a small, independent site for anyone who touches maps or coordinates — students, field surveyors, hobbyist mappers, and working GIS analysts alike. It is a set of free browser tools plus a museum of cartography, and nothing more than that.
The tools
Six calculators live here: the Coordinate Converter (decimal degrees to degrees/minutes/seconds and back), the Distance Calculator (haversine great-circle distance between two points), the Bearing Calculator (initial great-circle bearing plus 16-point compass direction), the Map Scale Calculator (map distance to ground distance from a representative fraction), the Area Unit Converter (square metres through square miles and acres), and the GPS Precision Calculator (what each decimal place of a coordinate resolves to on the ground). Each one solves a single, specific problem rather than trying to be a full GIS suite.
How they work
Every calculator runs in your browser using standard geodetic formulas — haversine for distance, initial-bearing trigonometry for direction, plain ratio math for map scale and area conversion. Nothing you type is uploaded anywhere; there is no account, no file upload, no server round-trip to wait on.
Where the numbers come from
The methods behind these tools — the haversine formula, degrees/minutes/seconds notation, representative-fraction map scales, standard area units — are established geodetic and cartographic conventions, not something invented here. We keep the formulas recognizable rather than hiding them behind a black box.
The museum
Alongside the tools sits the Maps & Cartography Museum, a browsable history of charts and atlases, the instruments that measured the Earth, the satellites and GIS that map it today, and the geography of the planet itself. Every entry, image, and fact in it is drawn from Wikipedia and Wikimedia Commons.
Guides and articles
The blog and learn sections cover the same ground in plain language — coordinate systems, field workflows, map scale, and the rest — for when a calculator answer needs a bit more context around it.
Who this is for
If you need to convert a coordinate before an import, check how far apart two points are, work out what a map scale actually means, or decide how many decimal places your GPS data needs, these tools are built for that specific moment, not for a full workflow.
Straight talk about ads & advice
MobGIS is independent and supported by advertising. It is not affiliated with Esri, the USGS, or any mapping-standards body it discusses. Every result here is an estimate based on general geodetic conventions — not a substitute for professional surveying, engineering, navigation, or legal-boundary work. Verify anything that matters against authoritative sources and proper equipment before you rely on it.
Questions?
If something is wrong, confusing, or missing, get in touch.