Tag Archives: Interpolation

Daily Download 22: Splines and Curves

Since it was first published in 2009 my CSpline function has been the most popular download from this site.  CSpline (and various associated functions) is used to fit a series of cubic curves through specified points, allowing interpolation along a smooth … Continue reading

Posted in AlgLib, Beam Bending, Charts, Charts, Coordinate Geometry, Excel, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , , , , | 7 Comments

Spline Interpolation Alternatives

A recent post at Jon Peltier’s Blog looks at an “on-sheet” method of performing linear interpolation on a set of tabular data, and the following comments include a number of alternative ways of carrying out the same process, and also some … Continue reading

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 7 Comments

Interpolation Update

The interpolation functions in IP2.xls have been given an overhaul: The linear and quadratic interpolations routines have been modified to accept negative values. All the routines have been modified to convert the table range to an array, rather than using a … Continue reading

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , | 4 Comments

Another update to IP.xls

Following some suggestions from Mike Seymour I have modified my polyline intersection function, and added a new version. The changes are: The data ranges for the new function, IP4(), are entered as four separate ranges, so the X and Y … Continue reading

Posted in Excel, Maths, UDFs, VBA | Tagged , , , , | 1 Comment

Intersections, interpolations, and rotations

Amongst the many and varied functions provided by Excel (or as far as I know any other spreadsheet) there are none that provide a one step process for linear interpolation, finding the intersection points of lines, or conversion between polar … Continue reading

Posted in Coordinate Geometry, Excel, UDFs, VBA | Tagged , , , , , , | 37 Comments