In the following maps the same base information has been used throughout. The ONLY difference is presentation.
(This blog will be very useful for all students who may be asked about data presentation in their exams.)
North is at the top of all the maps/images.
Here have three maps of the seafloor plotted with contours. The top map shows every 100m, the middle map has a ‘fat’ contour every 200m with 50m contours inbeween, the bottom map is coloured by height with contours every 100m.
Above: Contours every 100m – steep slopes are very obvious here.
Above: Bold contours depicted every 200m with 50m contours inbetween. The round volcanoes can be seen more clearly here.
Above: Contours every 100m shaded by height.Red is high and blue is low. The contrast between high and low areas of bathymetry (seafloor) can be clearly seen in this map.
The next three maps show shading without contours:
Above: This is black and white shading. Really not very useful at all.
Above:Shading by height, better than the black and white image but lacks visible detail.
Above: Coloured map to nearest 100m blocks. The shape of the bathymetry is starting to to become more defined but detail and clarity are still missing.
Above: Image is illuminated from N/W at 50 degrees above the horizon. Ridges are clearly seen and the roughness of the seafloor is starting to become apparent.
Above: Image is illuminated from N/W at 50 degrees above the horizon but with a brighter light than the image above. The roughness of the seafloor is clearer. Ridges look white on one side and dark on the other. Volcanoes cannot be clearly seen. The smooth dome of the Ocean Core Complex stands out.
Above: This image has been illuminated from the N/E and 70 degrees above the horizon. Different features stand out compared to the image above. Volcanoes cannot be clearly seen.
These are coloured by height. The darker the shade the steeper the slope.
Above: Lightly shaded – round volcanoes can be seen quite clearly, though the roughness of the seafloor is not obvious.
Above: The shading in this map is greater. Steep slopes can be clearly seen as can the circular volcanoes. The roughness of the seafloor is more apparent.
Above: Here the shading is greater still. The steepness of slope, roughness of seafloor and volcanoes all stand out clearly. The smooth dome of the Ocean Core Complex with it’s distinct striations (scratches) can be seen with ease.
Each map type has advantages and disadvantages. With contours precise height variations can be calculated. Illuminations can give a real idea of the bathymetry, it is easy to understand – one can imagine standing in the valleys looking up at the Ocean Core Complex. Shading shows great detail in the bathymetry. All of these maps and images are useful to scientists. The least useful are probably the colour maps which the lack detail needed to give an understanding of the bathymetry of the area.
My view whist I had a cup of coffee earlier:
Nigel asleep 🙂 Not headless!!