The surface of the water is now at a 2” vertical height, and the line that is formed by the water on the surface of the object denotes the 2” contour. Now continue pouring liquid into the container until you reach the next inch mark. This line denotes an increment of elevation along the shaped surface of the object. Where the liquid meets the surface of the object, a line is formed that demarcates wet (below the line, in the liquid) and dry (above the liquid). Now pour a liquid into the container up to the first inch mark. Each one inch increment that you marked on the side of the tray represents a successive rise in elevation: 1”, 2”, 3” and so on. The best would be an object with a wavy, undulating surface, like a human face or the like.Īssign a zero value to the bottom of the container. A sphere would work, but it would work less well than a cone, for instance. The object should have an obvious bottom, top, and sides. Place an object in a deep container with one inch increments marked on the side wall of the container. It goes like this (you can do this, or just imagine doing it) : Of course, this is not actually the exact work and process that goes into developing a contour map, but it’s an easy way to think about it on the way to grasping the concept.Ī Thought Experiment for Comprehending ContoursĪnother way to think about it involves a kind of thought experiment. A contour line emerges at the edge perimeter of each cut, and once all the edge perimeters of all the cuts are perfectly overlaid, one onto the next, into a system of contours, then you have the basis of a contour plan or map. If you grasp the concept of a floor plan as representing a level horizontal section cut though a building at a static height above a datum (ie the floor surface), then you will grasp the concept of a contour map representing a series of successive, level, horizontal cuts at regular intervals through the ground. Sometimes elements that are beneath the surface of the floor are also shown dashed, but for the most part there is not a substantial presence of vertical information provided in a floor plan. Anything shown below the plane of the “cut” is shown as a solid line. There is a drawing convention that permits things above the plane of the plan to be represented by a dashed line. A floor plan handles the problem be representing two dimensions, the x and the y, on a static, level plane in space, usually at a height of three feet above the floor. The abstraction of a drawing arises from the fact that while every worldly thing manifests itself in (at least ) three dimensions, a drawing can only host two, and so something must be done with that third one. The datum may be mean sea level, but more likely in the present day the datum is a geodetic reference.Įach contour line represents an interval of vertical elevation, or height, and the spacing of the lines represent the steepness or gentleness (or flatness) of sloping land.Īny drawing or map is an abstraction of the three dimensional world in which we live, and some are more abstract than others. The conceptual beauty comes from the contour line itself.Ī contour is a line, very often curved, that is shown on a topography plan connecting points of equal height as related to a datum. The literal beauty stems from the shapes that can seem to pop off the page and the color combinations that some maps are created with. They are not only informative, but also quite beautiful, both literally and conceptually. Have you seen maps covered with swirling, curly lines and wondered what that’s all about? Contour maps are two-dimensional maps or surveys or site plan drawings that are imbued with elevation information through the expression of those lines curving and swirling in spaced proximity to each other.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |