MAMmodeller

The Method for Aperture Meridians (MAM) has been devised by Richard Kittler and Stan Darula of the Slovak Academy of Sciences.  It provides a way of computing the luminance of the sky as seen through a rectangular window opening (vertically orientated) for any given solar position, window orientation and chosen sky model.

The MAMmodeller program has been developed by Geoffrey G Roy.  The Applet version can be run from the button below.  the standalone application can be downloaded and installed from here.  The stand alone version is freely available for non-commercial use.

A Java Runtime Environment (1.4 or later) is required, this can be downloaded (freely) from http://java.com

The input parameters are described as follows:

Time and Location Settings

Field Description
Lat (deg) The latitude of the location (deg), -ve for southern hemisphere
Lat (min) The minute component of the latitude
Long (deg) The longitude of the location (deg), -ve for west of Greenwich.
Long (min) The minute component of the longitude
Ref Long The reference longitude for the local time zone (deg), -ve for west of Greenwich.
Choose City Choose one of some built-in city locations, sets Lat, Long and Ref Long to match.
Month The Month of the year
Day The day of the month
Hour The hour of the day (24 hour clock)
Minute The minute of the hour
Enter Button Computes the altitude and azimuth of the sun, and transfers these values to the Solar Altitude and Azimuth fields in the Sky Information section.

Sky Information

Field Description
SSLD No The chosen sky model number (1 to 15)
Solar Azimuth The azimuth of the sun measured clockwise from North (deg) in the range -180 to +180
Solar Altitude The altitude of the sun measured up from the horizon (deg) in the range 0 to 180
Dv/Ev Used for overcast skies (SSLD  1 to 6), or if SunShaded is checked
Tv Used for overcast skies (SSLD  7 to 15), and if SunShaded is not checked
Sun Shaded If checked, the sun is presumed shaded for all SSLD models.  In this case the set, or default, Dv/Ev ratio is used.  This selection overrides the default behaviour as determined above.

Window Geometry

Field Description
Height The height of the window opening (m)
Width The width of the window opening (m)
Sill Height The height of the bottom of the widow above the ground level (m)
Window Azimuth The direction of the normal (outward) to the window opening measured clockwise from North (deg)
Distance from window The distance of the point of interest (or viewing point) inside the room from the window measured normal to the plane of the window
Point offset The distance of the point of interest to the right of the centre of  the window when facing the window.
Point Height The height of the point of interest above the ground.
Ext Obstruction Alt The altitude of an infinitely long external obstruction to the sky as measured from the point of interest, and normal to the window plane.
Blind height The height of a semi-transparent blind measured down from the top of the window.
Blind Transmission The visible light transmission of the blind (0% means completely opaque, 100% means fully transparent).

Display Settings

Field Description
Display Width The (maximum) width of the graphics display (pixels).  The height is scaled in proportion to the height of the window opening.  The actual width may be less then the maximum if the True View option is checked.  If the width specified means that the display will be wider or higher than the screen, it will be scaled to fit.
Relative/Absolute values Selects luminance values relative to zenith (when normalized to 1.0), or estimated absolute values.
Smooth/Contoured surface Selects a smooth surface, or a contour-like plot.
Shaded For a contoured surface, if checked the display is shaded, otherwise iso-luminance contour lines are drawn
Retain Samples If checked, point samples marked on the display are retained when the display is redrawn, copied or printed.
Linear/Log Scaling Selects a linear or logarithmic scaling for the surface shading
Fixed Range Fixes the maximum range of luminance values to the value set.
True View If checked, the width of the window is scaled the reflect the viewing angle from the point of interest.
Show Sun Shows the position of the sun (if visible through the window); as a yellow spot for clear skies or a black circle for overcast skies.

Instructions

  1. Click the button above to start the program
  2. Set the required parameter values.
  3. The solar azimuth and altitude can be entered directly in the Sky Information section, or the location and time values can be set for the chosen location, then clicking the Enter button will compute the solar azimuth and altitude and insert these values into the Sky Information section.
  4. A number of city locations have been built-in and can be selected from the combo box.
  5. Click on the Display button - a window showing the luminance distribution on the plane of the window as seen from the viewing point is shown.
  6. To discover the luminance values at any point in the window, click with the left mouse button.  The luminance at the point at the cursor is displayed at the bottom of the display when the cursor is moved.
  7. To clear the display of point values (if Retain Samples is not selected), chose Clear from the File menu
  8. To print the display chose Print from the file menu.
  9. To save the display as a JPEG file, choose Save from the File menu (application version only).
  10. To copy the display to the clipboard, choose the Copy options from the File menu,
  11. To observe a summary of the computational parameters, choose the Statistics option from the File menu.
  12. The Save/Load options available in the menu (of the standalone version) allow particular models/configurations to be saved/loaded for later use.