GeoMiner Free earth-science tools

Built by a geologist

Free Stereonet Plotter

A stereonet is a two-dimensional projection of three-dimensional orientation geometry. Structural geologists use stereonets to display planar features such as bedding, foliation, cleavage, faults, joints, veins, dikes, and excavation surfaces, and linear features such as fold axes, mineral lineations, slickensides, and intersection lines. GeoMiner provides a lower-hemisphere equal-area, or Schmidt, projection for planar right-hand-rule strike and dip measurements. It draws each plane as a great-circle arc, optionally draws its pole as a point, preserves input order through colour, reports simple descriptive dip summaries, provides a normalized table, and exports the visible plot as a standalone SVG. It does not require an account. Start with the convention. Strike is the azimuth of a horizontal line on a plane, and the same unoriented strike line has two reciprocal bearings. A strike value is incomplete unless the convention or dip direction is known. This plotter uses right-hand-rule strike. Looking along the entered strike azimuth, the plane dips to the right. Dip direction is therefore strike plus 90 degrees clockwise, normalized to the range from 0 through less than 360 degrees. Dip is the maximum downward inclination of the plane measured perpendicular to strike. GeoMiner accepts strike from 0 through 360 degrees, treats 360 as 0, and accepts dip from 0 through 90 degrees. Do not paste quadrant notation, dip-direction-and-dip pairs, trend and plunge, rake, or azimuths referenced to an unstated north system and assume they are equivalent. Convert them deliberately first. Paste one strike,dip pair per line. Commas, tabs, semicolons, and spaces are accepted, which supports ordinary spreadsheet columns and copied CSV rows. A first header row containing strike and dip is ignored, as are blank lines and comment lines beginning with . Every other row must contain exactly two finite numeric values inside the allowed ranges. If any row is invalid, the calculator does not keep a stale plot or silently omit that row. It lists row-specific errors and asks for correction. The dataset is bounded at 250 measurements to keep the interactive plot responsive and the table inspectable on field devices. The geometry begins with a reference sphere centred on the observation point. A plane through that centre intersects the sphere along a great circle. Only the lower-hemisph

Verification resources

Cross-check terminology, classification, methods, and safety with these authoritative external resources.

  • undefined. Shows lower-hemisphere equal-area stereonets used for poles to planar structures, contoured orientation populations, mean great circles, and structural interpretation.
  • undefined. Explains lower-hemisphere Schmidt-net conventions: planar structures plot as great circles, linear structures plot as points, and poles are lines perpendicular to planes.
  • undefined. Documents right-hand-rule strike, dip, lineation, and apparent-dip geometry, including the importance of internally consistent structural measurements.
  • undefined. Provides a published lower-hemisphere equal-area pole plot and states that strike is normalized so dip direction is 90 degrees clockwise from strike.

Read GeoMiner's editorial methodology.

Common questions

What does a plane look like on a stereonet?
On a lower-hemisphere stereonet, a plane plots as a great-circle arc. Its pole plots as the point where a line perpendicular to that plane intersects the lower reference hemisphere.
Is this an equal-area or equal-angle stereonet?
GeoMiner uses a lower-hemisphere equal-area, or Schmidt, projection. Equal-area projection preserves area density and is commonly used to inspect orientation populations. It is not interchangeable with an equal-angle Wulff net for every graphical construction.
Which strike convention does the plotter use?
Every input row uses right-hand-rule strike. Looking along the entered strike azimuth, the plane dips to the right, so dip direction is 90 degrees clockwise from strike.
Can spreadsheet data be pasted?
Yes. Paste one strike,dip pair per line with comma, tab, semicolon, or space separators. A strike,dip header and lines beginning with # are ignored. The plot is limited to 250 measurements.
Does the plotter calculate structural sets or stability?
No. It plots entered planes and poles and reports descriptive dip summaries. It does not contour density, fit girdles, calculate eigenvectors, identify sets, perform kinematic analysis, or determine slope, tunnel, wedge, or excavation stability.
Are structural measurements uploaded?
No. Pasted measurements, projected coordinates, and the exported SVG are processed locally in the browser. Product analytics retain only bounded action, display-mode, result-status, and dataset-size categories.

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