Philosophy of science, and maps as important scientific tools.

What activities characterize science?

Journal writing exercise: Can your dog do science? A dog can follow a scent trail. The dog collects information with his nose. The various scents have to be classified at least into two categories, quarry and not quarry. Their behavior, e.g. following the more recent trail, suggests they can make decisions based on the input. With barks the dog can convey information to other dogs and humans. The dogs can learn from their experience. How, fundamentally, is what a dog does when following a scent different from science conducted by humans?

Some useful concepts in considering science:

Science is a human activity, and that context is especially important for this linked course. What is shared by a scientific community? Kuhn's suggestion as to four critical components are:

A flow diagram for the scientific method of development of exemplars.

What do you do if you don't like the answer, or explanation, or model that results from a scientific investigation?


Data is the lifeblood of science. Data has different value in different contexts. It is the data-question pairing that is crucial, that can produce answers.

Types of symbolic data:

What are fundamental measures in physical science:

Examples of environmental data?


In class exercise: You will get into groups of 4-5 and be given a map, or you can bring one to class. Use it and the material discussed so far to answer the following questions (We plan for this to take about 15-20 minutes).

Be prepared to discuss your results in class.


Why are maps important in environmental science and endeavors?

Definitions of a map:

Clarke: "A depiction of all or part of the earth or other geographic phenomenon as a set of symbols and at a scale whose representative fraction is less than 1:1."

Glossary of geology: " A graphic representation , usually on a flat surface, of selected physical features (natural, artificial or both) of a part of the whole of the surface of the earth, some other planet, the Moon, or any desired surface or subsurface area, by means of signs and symbols and with the means of orientation indicated, so that the relative positiona and size of each feature on the maps corresponds to is correct geographic situation according to a definite established scale and projection."

Webster dictionary: "a representation, ususally on a flat surface, of the whole or part of an area."

Harley and Woodward: "graphic representation that facilitate a spatial understanding of things, concepts, conditions, processes or events in the human world."

Harmon's: An image depicting the distribution and or position of a feature or features in some sort of space.

Genetic maps, geologic maps, geographic maps, phase maps, computer maps, mental maps - the list goes on. How many more maps types can you add?

Graphs as maps or maps as graphs?

Link to 321 definitions of the word 'map'.


What is your space, your coordinate system?

What is being mapped?


Spatial patterns of point distributions:


Contouring a continuous surface from point sampling:

The most common type of contour map of a continuous surface you might be familiar with are USGS topographic maps. These are widely used and distributed. However, there are many other examples of contour maps.

Imagine you would like to know what the distribution of a toxic compound is in ground water in an area. You can drill wells and take samples and have them analyzed for how concentrated a given toxin was in a sample from a given well. But what is the larger hidden pattern of toxin concentration invisible to the eye, but sampled by the wells. You might imagine putting a drop of dye in water to represent a point source of toxin in the ground. The dye spreads with time. The concentration of the dye and the color of the water will at first be greatest right at the source, and diminish with distance. A contour line is simply a line that separates one part of a surface where values are higher than the contour line value from the other part where values are lower. Contour lines of concentration and/or color would produce a bullseye pattern around the source. Contaminants in groundwater can move in additional ways to simple diffusion (which is what happens in the case above), and thus the pattern of the contours can vary from this pattern. We can contour the values of the toxin concentration for the wells to visualize what is happening in the ground. A simple rule is that a given contour line for a given concentration needs to consistently separate wells (points) that are higher than the contour line value from those that are lower. In addition, contour lines can't cross. It is useful to practice hand contouring to gain real understanding. This is a link to a practice exercise.

Surfer and other software programs will contour more systematically than doing it by hand.

DEMs (Digital Elevation Models) are gridded files of elevation, and are used for better understanding topography and earth processes. Computer programs can turn them into shaded relief images.

Above is a shaded relief image of elevations from part of Nebraska. From the top to bottom boundary of the image is about 8.8 miles. Where in Nebraska do you think this comes from? Why? What type of landscape features are depicted here? What environmental significance does this landscape have?

Some examples.

More detailed notes from the Geodata course for the curious.


References:

Clarke, 2000, Getting Started with Geographic Information Systems; Prentice Hall, 352 p..