Category Archives: Coordinate Geometry

Arc-spline update

Posted on September 9, 2018 by

The input for the first version of the Arcspline function required the coordinates of the centre of each arc, as well as the angle of the tangents at each end of the arc.  I have now added a new version with … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , | Leave a comment

Using VBA Evaluate as an Array Function

Posted on August 24, 2018 by

I recently discovered from a thread at  Chandoo’s Excel Forum that the VBA Evaluate function can be used as an array function.  As a simple example: Range(“A11:A16”).Value = Evaluate(“= B11:B16 + C11:C16”) will add the values in columns B and C, … Continue reading →

Posted in Arrays, Coordinate Geometry, Excel, Maths, UDFs, VBA | Tagged , , , , | 2 Comments

Arcs and arc-splines

Posted on August 17, 2018 by

I have added two user defined functions (UDFs) to the IP2 spreadsheet to generate coordinates for a single  arc, or a series of arcs connected (if necessary) by straight lines.  The new version may be downloaded from: IP2.zip As an example … Continue reading →

Posted in Animation, Charts, Charts, Coordinate Geometry, Drawing, Excel, Maths, UDFs, VBA | Tagged , , , , , , | 1 Comment

Using Section Properties- Group

Posted on June 24, 2018 by

Following a recent comment I have updated the documentation for finding the section properties of groups of shapes in the Section-Properties-Group spreadsheet.  The revised file can be downloaded from: Section Properties07-Group.zip The screenshots below illustrate use of the Group function to … Continue reading →

Posted in Coordinate Geometry, Excel, Maths, Newton, Numerical integration, UDFs, VBA | Tagged , , , , , | Leave a comment

IP2_py Update for Python3

Posted on April 28, 2018 by

The spreadsheet IP2_py provides a large number of geometric functions, including intersection points of lines, circles and planes, interpolation, rotations, and converting between coordinate systems.  Many of the functions are available in VBA and Python versions.  The Python code has now … Continue reading →

Posted in Coordinate Geometry, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , , , , | Leave a comment

xlwSciPy update for Python 3

Posted on April 9, 2018 by

The xlwSciPy spreadsheet allows a wide variety of the science and maths functions in the Python Numpy and Scipy libraries to be called directly from Excel.  The spreadsheet has now been updated for use with Python 3.  The spreadsheet and … Continue reading →

Posted in Coordinate Geometry, Differential Equations, Excel, Link to Python, Maths, Newton, Numerical integration, NumPy and SciPy, Python Pandas, UDFs, VBA, xlwings | Tagged , , , , , , | 1 Comment

More circle fitting options with Scipy

Posted on March 17, 2018 by

A comment on the first post on this topic found that the method used did not work well for short arcs of large radius circles.  An example of the problem can be seen in the screen shots below: The function … Continue reading →

Posted in Coordinate Geometry, Curve fitting, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , | Leave a comment