Lecture 3 Flashcards
configuration or shape and roughness of the ground
Topography
“Topos” + “Graphein”
place + write
“Topographia”
a description of a place
process of determining the positions, on the earth’s surface, of the natural and man-made features of a given locality and the configuration of the terrain
Topographic Survey
shows, through the use of suitable symbols, the spatial characteristics of the earth’s surface such as hills and valleys, vegetation and rivers, and constructed features such as buildings, roads and canals
Topographic Map
indicate the elevations at particular points
Spot Heights
consists of rows of short and nearly parallel lines (arrows) whose spacing, and direction produce an effect similar to shading
Hachures
line joining points of equal elevation on the map, also called “isohyps”
Contour Lines
also known as “depth curves”, used to portray the ground under water bodies such as lakes, seas, oceans, etc.
Subaqueous Contours
main streams and tributaries are drawn in blue solid lines, main ridges are drawn as brown dashed lines
Ridge and Stream Lining
resemble contours but are not drawn with the same degree of accuracy
Form Lines
each elevation zone is indicated by a distinctive color or tone between the bounding contours
Layer Tints
an assumed light source from the northwest is imagined as creating areas of light and shadow in a mountainous area
Shading
drawn as if they were illuminated by a light source from the upper-left corner of the map
Illuminated Contours
a pictorial representation of the surface drawn from a viewpoint in space
Block Diagram
a representation of the terrain done in 3D to suitable horizontal and vertical scales, a miniature of the terrain it represents
Relief Model
TYPE OF CONTOUR: Defined as every fifth contour (usually) in which the line thickness is made heavier than the rest.
INDEX
TYPE OF CONTOUR: Defined as lighter weight contours found between index contours.
INTERMEDIATE
TYPE OF CONTOUR: Used in areas that are so flat that the contours are far apart (to better depict the relief), Drawn as dotted lines or dashed lines.
SUPPLEMENTAL
TYPE OF CONTOUR: Used to show low spots (i.e. excavations around which contours close in).
DEPRESSION
TYPE OF CONTOUR: For areas where the elevations are not accurately determined.
APPROXIMATE
the cross-sectional view through a particular piece of terrain
Profiles
