Aspect of Map Projection

The aspect describes the mutual position of the axis of the earth and the axis of the projection.


Earth and axes

The axis of the earth (black) and the axis of a projection with transverse aspect (red)

Axis of a Projection

The axis of the earth joins the north pole with the south pole. With any map projection one can associate an axis which joins a distinguished point of the globe with its antipodal point.

Normal Aspect

Normal aspect means that the two axes coincide.

For example, under conical and azimuthal projections the north pole will always be displayed in the centre of the map. On the other hand, cylindrical and pseudo-cylindrical projections display another point in the centre of the map, namely the point (0° E, 0° N), i. e., the point where the meridian of Greenwich meets the equator.

Transverse Aspect

Here the axis of the projection belongs to the plane of the equator.

In all our maps the point off the African coast with geographical coordinates (0° E, 0° N) takes over the role of the north pole.

Aspects

Aspects of our map projections

Oblique Aspect

If the axis of the projection is neither normal nor transverse then one speaks of an oblique aspect.

Our series of pictures are based on axes through one of the following cities:

  • Vienna (16°E, 48°N), Austria
  • Kathmandu (85°E, 28°N), Nepal
  • Dili (126°E, 9°S), Timor-Leste
  • Regina (105°W, 50°N), Saskatchewan, Canada
  • Stanley (60°W, 52°S), Falkland Islands

Other Settings

Rotation

This will rotate the globe about the axis of projection by 0°, 90°, 180° or 270° before it is displayed. The effect is a change of the image, which depends on the chosen projection.

Display

  • Standard: A part of the globe (e. g. a hemisphere) is displayed.
  • Wide: The entire globe is displayed or, if this is impossible, at least a wide part thereof.

For some projections there will be no difference between the two pictures, because both of them display the entire earth.

Source(s) and Link(s): DGGS

PROJECTIONS

Choosing Map Projection

Mercator’s Projection

Classes of Map Projection

Latitude and Longitude

Zenith and Nadir

Right Ascension

 

Advertisements

About Rashid Faridi

I am Rashid Aziz Faridi ,Writer, Teacher and a Voracious Reader.
This entry was posted in Class Notes, earth, Geography Practicals/Lab and Statistical Techniques, map making. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.