The Menu »Projection Data«

 Menu »Projection Data«

After selecting the menu item »Change Projection Data ...« the dialog field »Projection Data of ...« will appear. Here you can vary diverse projection data.
Please click onto the part of the dialog field to which you want get informations.

  
 dialog field »Projection Data«
 Projection Radius  Point of Perspective
 dialog field »Projection Data«
 Location of Projection Axis  Standard Parallels
 dialog field »Projection Data«
 Renumeralisation
 dialog field »Projection Data«

Projection Radius

For fixing the radius the measuring units »inches«, »millimeters« (mm) and »pixels« are available. In this matter inches and millimeters (mm) regulate the proportions of any printer output of the map.

Point of Perspective

The input of the distance between the point of perspective and the centre of the Earth for vertical perspective projections takes place as a multiple of the radius.

Location of Projection Axis

If the projection axis is identical to the pole axis, the chosen projection is called regular- or normal-axial.

This is normally the preset location of the projection axis (marker ).

You can locate the projection axis at a general position if the selected projection allows this. Then we talk about a so-called oblique-axial projection.

If the projection axis joins the equatorial plane (geographic latitude v = 0 degrees / geographic longitude u any choice), it is a matter of transverse-axial projection.

Standard Parallels

Here you are able to select the standard parallels, if there are any for the chosen projection. In this case you have to note the special facts of the cylindrical resp. the conic projection concerning valid standard parallels.

Renumeralisation

If you are just working with a renumeralised projection you are able to vary the »scale constants« and the »grid numeral constants« on trial. Nevertheless, you will recognize that as a result the constructed projection is not allways a »beautiful« one.

Please note:
For equal-area renumeralisation the product of the constants C1, C2, C3 and C4 is equal to 1.

  
See also
  
 Systematics of Map Projections Systematics of Map Projections
  
To the beginning of the chapter
  
 The control system of GridMaps The control system of GridMaps