The island of Ireland comprises a large central lowland of limestone with
a relief of hills surrounded by a discontinuous border of coastal
mountains which vary greatly in geological structure. The mountain ridges
of the south are composed of old red sandstone separated by limestone
river valleys. Granite predominates in the mountains of Galway, Mayo and
Donegal in the west and north-west and in Counties Down and Wicklow on
the east coast, while a basalt plateau covers much of the north-east of
the country. The central plain, which is broken in places by low hills,
is extensively covered with glacial deposits of clay and sand. It has
considerable areas of bog and numerous lakes. The island has seen at
least two general glaciations and everywhere ice-smoothed rock, mountain
lakes, glacial valleys and deposits of glacial sand, gravel and clay mark
the passage of the ice.
Two visualization methods were combined to produce this image: shading and
color coding of topographic height. The shade image was derived by
computing topographic slope in the northwest-southeast direction, so that
northwest slopes appear bright and southeast slopes appear dark. Color
coding is directly related to topographic height, with green at the lower
elevations, rising through yellow and tan, to white at the highest
elevations.
Elevation data used in this image were acquired by the Shuttle Radar
Topography Mission aboard the Space Shuttle Endeavour, launched on Feb.
11, 2000. SRTM used the same radar instrument that comprised the
Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)
that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed
to collect 3-D measurements of the Earth's surface. To collect the 3-D
data, engineers added a 60-meter (approximately 200-foot) mast, installed
additional C-band and X-band antennas, and improved tracking and
navigation devices. The mission is a cooperative project between NASA,
the National Geospatial-Intelligence Agency (NGA) of the U.S. Department
of Defense and the German and Italian space agencies. It is managed by
NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth
Science Enterprise, Washington, D.C.
Location: 53.5 degrees North latitude, 8 degrees West longitude
Orientation: North toward the top, Mercator projection
Image Data: shaded and colored SRTM elevation model
Date Acquired: February 2000
