These are the parameters that are used in traditional gnomonics: they are based on the use of an intermediate local reference. In Calcad you supply this reference via the Place details, which are optional and can be approximate. While the parameters can take different values, they do form a coherent set that allows you to draw all the lines of the dial identically, except, of course, the horizon line. This reflects the principle of the "sundial out of place" which is well known by gnomonists: a sundial that has been properly designed for a given geographic situation can be used elsewhere provided that you change its orientation appropriately.
o Time zone
The value from the input box if the localization is complete, otherwise 0.
o Longitude
The value of the input box, in other words the real geographic longitude, if the localization is complete. Otherwise the zero meridian of Greenwich is replaced by the one where the mean sun is located at midday (in standard or daylight saving time, corresponding to the time used to record the shadow points). The value is positive if the sundial is to the west of the zero meridian, negative if it is to the east.
o Latitude
The value of the input box when the localization is complete, otherwise the latitude of the equivalent horizontal sundial. The latitude is positive in the northern hemisphere and negative in the southern.
o Declination
Zero if the sundial is not localized, otherwise the orientation of the sundial plane, measured as the angle with respect to south. The declination is positive westwards (0 to 180°) and negative eastwards (0 to -180°).
o Inclination
Its value is 0 if the localization is not complete. Otherwise it the slope of the sundial plane: 0° for a horizontal sundial is 0° and 90° for a vertical sundial. The inclination varies from 0 to +180°.
o Rotation
If you enter the other data in classical sundial software, the result must be rotated by this angle, anticlockwise if the value is positive, clockwise if it is negative.