Buffers and range rings in Surfer are quite different. Range rings are concentric circles or squares drawn outwards from a user-defined centerpoint, whereas buffers are concentric shapes drawn within or around existing polygons, polylines, points, or other objects. For a more in-depth comparison of the two, see the table below.
|Creation||Add to existing objects (points, polylines, spline polylines, polygons, rectangles, rounded rectangles, and ellipses).||Draw independently of other objects by clicking where centerpoint should be.|
|Properties||Each buffer uses different line/fill properties.||Each ring uses the same line/fill properties. Can change properties of center point, including whether or not it is displayed.|
|Drawing order||Outer (bigger) polygons are drawn over the inner (smaller) polygons.||Inner (smaller) range rings are drawn on top of outer (larger) range rings.|
|Create multiples?||Select multiple objects to create a buffer around all at once.||Draw one range ring at a time.|
|Shape||Mirrors the shape of the selected object (circular for points regardless of symbol chosen).||Square or circle.|
|Combining rings/buffers||Can choose to combine overlapping polygons. Doing so also combines all buffer polygons into one complex polygon.||Must use Union of Polygons to combine overlapping range rings.|
|Concentric rings/buffers||Can specify number of concentric buffers, in map units if part of a map layer.||Can specify number of concentric range rings, in map units if part of a map layer.|
|Distance from||Distance from the edge of the object.||Radius from the center point.|
|Negative distance?||Distance can be negative for all but points and polylines. This denotes the buffer will be drawn inside the object rather than outside.||Radius cannot be negative.|
Circular and square range rings can be displayed around a user-defined center point. All rings share the same fill and line properties, and the line opacity is additive.
Buffers can be added to most object types, including polygons (left), points (middle), and polylines (right). Buffers can have unique line and fill properties (shown here with fill patterns). Fill opacity is additive.
Updated September 18, 2017