Contour line
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Contour lines are curved or straight lines on a map describing the intersection of a real or hypothetical surface with one or more horizontal planes.
Contour lines Lines on the map connecting points of equal elevation above mean sea level; using contour lines, relief features can be profiled into a three-dimensional perspective.
Contour Line Editing and Labeling
R2V provides the best Line Editor, designed for quick map editing. People around the world use it on a daily basis for large and small mapping projects.
contour line : An imaginary line joining points of equal elevation
control points : A set of points on the ground whose horizontal and vertical location is known. Control points are used as the basis for detailed surveys ...
Contour Line - A line on a map or chart that connects to points which are at the same elevation.
Contour Map - A map that defines topography (hypsography) by interpreting contour lines as relief.
Contour Line Extraction from a Difficult Topo Map using BLACKART
In the last article I demonstrated a general technique for extracting DEMs from well-behaved USGS topographic maps.
Contour lines can tell an informed reader many things about the shape of the land and its ruggedness. In its simplest terms, the closer contours are together the steeper the land and the further they are away from each other the flatter the land.
Contour lines
Polygons
Raster
Specified point locations
Geostatistical layer that stores the model parameters for the renderers used ...
Contour lines are not a good form in which to store elevation data. Contours are derived data, data interpolated from information of altitude at known points, and in themselves offer no information about the surface morphology between them.
A contour line is an isoline that connects all points on the Earth's surface that have the same elevation. On topographic maps, contour lines are drawn at a uniform vertical distance known as the contour interval. Many maps also use index contours.
Ex. Contour lines connect points of equal surface value.
D
Dangling node - the endpoint of a dangling arc not connected to another arc.
Data type - The characteristic of columns and variables that defines what types of data values they can store.
2) Contour lines can never cross one another. Each line represents a separate elevation, and you can't have two different elevations at the same point.
See Also: contour line
[cartography] Lines on a map that approximate the shape of terrain in lieu of actual contours. Form lines do not refer to a true datum and do not necessarily use regular intervals.
7. Are the contour lines closer together on Able Hill or Baker Hill?
Baker Hill
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Here are the contour lines placed atop the watersheds. The watershed boundaries do a fairly good job of following ridge lines.
And if you have a difficult time visualizing contour lines, here is an analytically hillshaded DEM.
The location in a contour line marking the intersection with a linear feature.
Browse
To be able to select and take a quick look, at part of a map or database to check for features of interest. Usually no analysis or data manipulation is involved.
Hypsometric tints The technique of colouring in elevation ranges between contour lines to enhance the visual picture of a landscape.
Contour Line: A set of points representing the same value of a selected attribute and forming an imaginary line. The terms contour or contour line is most commonly used for lines connecting points on the ground having the same elevation.
A map that shows the change in elevation over a geographic area through the use of contour lines. The contour lines trace points of equal elevation across the map. See also: contour line and contour map.
Topography: ...
Initially, a vector map of the contour lines is made with the elevation of each line as an attribute. When the program v.to.rast is run on the vector map, continuous "lines" of rasters containing the contour line values will be the input for r.surf.
Variations in the third dimension, from which one is able to envision changing surface curvature and to calculate relative heights of different points on the surface, can be depicted on maps by using contour lines.
Now use the Vector Line create tool, Mtool:3b,3 to make a 2-D contour line at elevation zero, and make a contour that nips off the south-east corner (about a quarter) of your site boundary. see picture.
A surface model was generated from elevation contour lines digitized from topographic maps at 50 m intervals by creating a triangulated irregular network (TIN), ...
Now we shell create a continuous surface from contour lines. Before we start this job we have to separate two different type of information given by the dxf file. It contains contour lines and the boundary of the study area.
The most commonly used method is to plot contour lines joining points of equal height or depth. The difference in elevation between contour lines is known as the contour interval.
You should now see your contour lines overlaid on top of your elevation raster.
SURFACE II - This early computer-mapping program mostly dealt with the mapping of surfaces and contour lines. Its origins extend from the Kansas Geological Survey, who produced this software package during the 1970's and 80's.
Contour lines and triangulated irregular networks (TIN) are used to represent elevation or other continuously changing values. TINs record values at point locations, which are connected by lines to form an irregular mesh of triangles.
Explore the elevations in more detail by creating contour lines with the contour tool . Because it is a tool, you must apply it to a location on the grid.
For example, road lines as well as hydrology and contour lines must connect at endpoints and not self-overlap; connected contour lines must have consistent elevations; ...
Different features of the topography such as contour lines, boundary lines, rivers, lakes, forest areas, vegetatin areas, dwelling areas, houses, fields, roads, streets, etc, were digitized in specific layers.
topographic map See: map, topographic topography Configuration (relief) of the land surface; the graphic delineation or portrayal of that configuration in map form, as by contour lines; ...
From the scanned contour lines, elevations were sampled every 3 arc-seconds of latitude and longitude (approximately every 90 m).
Figure 19a. Shaded-relief map and contour lines generated from the digital elevation model in the study area.
Figure 19b. Map showing the steepness of slopes in the study area, created by GIS from the digital elevation model.
A map depicting terrain relief showing ground elevation, usually through either contour lines or spot elevations. The map represents the horizontal and vertical positions of the features represented.
In contrast, cartographic features such as roads, boundaries, buildings, and contour lines usually are represented in vector form. In digitizing a lake, for example, the shoreline can be indicated as a series of points and line segments.
Reopen the Geoprocessing wizard and merge this theme with your point theme you've created for all your contour lines.
The most frequent example is surface terrain often represented by contour lines which have an elevation value. This concept can be applied to other spatially continuous data as well.
For example, the calculation of slope is much more exacting than ocular estimates of contour line spacing. And the calculation of visual exposure to water presents a completely new and useful concept in natural resources planning.
Contour Mapping: Display of contour lines, each of which represents a constant value, typically surface elevation, throughout its length.
e.g. effects of mis-tagged contours in the products of scanned contour lines
Uses of DEMs
determining attributes of terrain, such as elevation at any point, slope and aspect ...
These can be used to generate contour lines and Triangulated Irregular Networks (TINs) which look like wire frame representations of the terrain. They are also used in the process of orthogonalizing air photos.
Contour Interval - The difference in elevation of two adjacent contour lines. Typical contour intervals are 1', 2', 5' and 10'.
Label - A text string that describes a geographic object in a digital map, e.g. elevation value of a contour line. Unlike annotation, labels are used for display, query and analysis purposes. In some systems, labels are also known as Tags.
The relief of ocean and lake floors. Bathymetry is usually measured in units of distance below mean sea or water level and is mapped using contour lines called isobaths in a similar fashion to terrestrial topographic maps.
Bearing ...
County boundary must not have dangles (i.e., must be closed)
Contour lines must not intersect
Label points must be properly inside polygons
Census tracts and counties must cover each other ...
Features are drawn on these 'topo' maps as if seen from above, know as a plan view, along with lines of equal elevation, known as contour lines, to show the changes in elevation.
Topographic maps show the shape of land surface with contour lines. The actual shape of the land can be seen only in the mind's eye.
In order for every station to be within the correct contours, lines would be zigging and zagging everywhere, making the map unreadable. Fortunately, contour lines are smoothed to make the map readable.
Fragment of the Dutch topo map showing the border of Belgium and the Netherlands. The Mean Sea Level of Belgium differ -2.34m from the MSL of The Netherlands. As a result , contour lines are abruptly ending at the border.
Curve Fitting An automated mapping function that converts a series of short connected straight lines into smooth curves to represented entities that do not have precise mathematical definitions (such as rivers, shorelines, and contour lines).
Using an SQL statement [Figure 4] a buffer is created around the ensemble of selected grid points. The resulting polygon is used as a contour line representing the limits of coverage for the specified position error.
 See also: Contour, Map, Information, Elevation, Surface
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