Free GIS tools

Quick answers for everyday GIS work.

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Coordinates

Coordinate converter

Paste a coordinate in any common format, or switch to UTM, to get decimal degrees, degrees-minutes-seconds, degrees and decimal minutes, and UTM (WGS84).

Need coordinates cleaned up for a whole dataset? We can help.

Map scale

Map scale converter

Turn a representative fraction like 1:24,000 into a verbal scale ("1 inch = 2,000 feet"), or the other way round. Add a ground distance to see how long it will be on the map.

Planning a printed map series or atlas? See our mapping services.

Distance and area

Distance & area calculator

Find the straight-line (great-circle) distance and bearing between two points, or the area covered by a radius, such as a 5-mile service area.

Need drive-time areas or real network distances? Ask about site selection and access analysis.

Distance between two points

Area of a radius

For students and cartographers

Classification breaks

Paste the values you want to map, such as population density by county, and get class breaks for a choropleth map by natural breaks (Jenks), quantile or equal interval, with the number of features in each class.

Natural breaks groups similar values and maximises the difference between classes. The goodness of variance fit (GVF) runs from 0 to 1; closer to 1 is a better fit.

Mapping a whole dataset? See our demographic and census maps.

For students and field work

Slope & gradient

Work out slope from a rise and a horizontal distance, or straight from a topographic map: enter the contour interval you crossed, the distance you measured on the map, and the map scale.

Slope = rise ÷ run. 100% is 45°, not vertical.

New to slope? Read What is a slope map?

Slope

Measured on a map? Fill these instead of the run:

Vertical exaggeration for profiles

For students and data checks

Degrees to metres

How far is 0.0001°? It depends on where you are. A degree of latitude is always about 111 km, but a degree of longitude shrinks toward the poles. Enter a latitude to see real distances on the WGS84 ellipsoid.

Useful for choosing how many decimal places to keep, setting tolerances, and sanity-checking buffers made in degrees.

More on coordinates: Latitude, longitude and UTM explained

For students and map readers

Map distortion (Mercator)

Web maps use the Mercator projection, which keeps shapes locally true but stretches everything away from the equator. Enter a latitude to see how much bigger places are drawn there than at the equator.

Scale factor = 1 ÷ cos(latitude). Areas grow by the square of that. Web Mercator stops at about 85.05° north and south.

Why scale changes on screens: How to read a map scale

For planning and economic geography

Location quotient

Is an industry more concentrated in your area than in the nation, or another reference region? Enter employment for the industry and for all industries, locally and in the reference region.

LQ = (local industry ÷ local total) ÷ (reference industry ÷ reference total). Above 1 means a bigger share than the reference.

Need an economic base study? See our planning analysis services.

Employment

For planning students

Population projection

Project a population forward from two census counts using linear, geometric and exponential growth, and see the growth rate and doubling time.

Fitted to the same two counts, geometric and exponential growth give the same projection. They just express the rate differently: compounded each year, or continuously.

Planning for growth? See our demographic maps.

Census counts

For spatial statistics

Nearest neighbour index

Is a point pattern clustered, random or dispersed? Enter the number of points, the study area and the mean distance from each point to its nearest neighbour, or paste the points' x,y coordinates and let the tool measure them.

Clark and Evans index: R = observed ÷ expected mean distance. R below 1 is clustered, about 1 random, above 1 dispersed (2.15 is perfectly even). Use projected coordinates in metres or feet, not latitude/longitude.

Mapping hot spots for real? Talk to us.

Bigger than a quick calculation?

Let's map it properly.

From cleaning thousands of coordinates to full spatial analysis, we can take it from here.

Contact PentoGIS