Contouring surface maps
Sometimes the reported values (black numbers) are not always located between the correct contours.
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.
depth contour
See Also: contour line
[symbology] A line on a map connecting points of equal depth below a hydrographic datum.
Make a Contour Map and Genrate a Surface
Open a new FormZ project, and set the Options-Working Units to 'City'
Make a new layer named site_1, and make it active.
Make a 2-dimensional square approximately 200 feet on a side.
Contour lines connect a series of points of equal elevation and are used to illustrate topography, or relief, on a map. They show the height of ground above Mean Sea Level (M.S.L.) in either feet or metres and can be drawn at any desired interval.
If a contour level exactly matches a category value in the raster file, the contour line may backtrack on itself, causing illegal arcs to be produced in the output GRASS vector file.
This QGIS Contour Plugin is only capable of generating contours using point datasets. For the Vector layer, make sure that point_sampling has been selected.
CONTOUR MODELING THAILAND WITH R2V
The Environmental Information Center (EIC), an arm of Thailand's Environment Institute, is currently making daily, production-run use of R2V for Windows (32-bit version) on seven workstations.
Contour: A line connecting points of equal surface value.
Contour Interval: The difference in surface values between contours.
Contour Interval - The difference in elevation of two adjacent contour lines. Typical contour intervals are 1', 2', 5' and 10'.
Contour Vectorization
View demo [WMV]
Vectorization preview
Vectorization settings (compression tolerance)
Raster cleanup ...
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 ...
Contours
Quickly create a contour plot of model input (like ground elevations) or results (such as hydraulic grade line), and export these directly to MicroStation, AutoCAD, or DXF format.
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 Mapping: Display of contour lines, each of which represents a constant value, typically surface elevation, throughout its length.
Contour Interval
Difference of elevation between two consecutive contours. In general, one contour interval is used per data set.
Contrast ...
Index Contour, Infrared, International Date Line, Isoline,
Landsat, Latitude, Lithosphere, Longitude, ...
Mapping contours
If you have data representing a continuous surface, it is possible to create single contour lines for a given grid cell value, or to create a whole group of contour lines at a regular interval.
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 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 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.
contours can be "threaded" through the pixels along lines of constant value
the searching operation for finding contours is computer-intensive so may be slow
the surface can be shown in an oblique, perspective view ...
contour
A contour is a line on a topographic map that represents locations that have the same altitude.
cove
A cove is small, horseshoe-shaped body of water along the coast; the water is surrounded by land formed of soft rock.
Contour Interval
The spacing of contours. There is no standard for how many contours should appear on a map and how they are spaced in terms of elevation. The decision is usually based on the nature of the relief and the scale.
Contour Interpolation Program; Canadian Institute of Planners
CIR
Color infrared ...
7. Contour interval: this is to be shown in the lower margin near the graphic scales. It should be in the form: "Contour interval ... metres (or feet)". When necessary the note "Supplementary contours at ... metres (or feet)" is to be added.
B. CONTOURS GENERALLY TEND TO HAVE GOOD CONNECTIVITY AND PARALLELISM.
2. LAPLACEAN FILTERS - USED FOR INITIAL ESTIMATE OF SURFACE FROM RAW DATA DERIVED BY SOME INTERPOLATION PROCEDURE.
...
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.
Figure 15. Contour map made from soil pH values shown in figure 14.
The way maps and other data have been stored or filed as layers of information in a GIS makes it possible to perform complex analyses.
Coverage Contours
To compute error contours a new grid is produced with four times the number of points as in the original grid. Grid points between original points are interpolated from neighboring points.
The distance contours form "bubbles" around each middle school location. Bubbles meet at points equidistant from the two centers--that is, along the perpendicular bisectors of the lines joining two schools.
The nature of contours is examined in more detail. This is done by showing several topographic maps that show how contours express elevations. Several rules regarding interpretation of slopes and heights from contour spacing are given.
: Machine contouring using minimum curvature. Geophysics. Vol. 39, No. 1. February 1974. pp. 39-48.
(Collins and Bolstad 1996) F. C. Collins, P. V. Bolstad: A Comparison of Spatial Interpolation Techniques in Temperature Estimation.
1. A map containing contours indicating lines of equal surface elevation (relief), often referred to as topo maps.
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.
map, bathymetric Maps delineating the form of the bottom of a body of water, or a portion thereof, by the use of depth contours (isobaths).
30 a line connecting points of equal elevation on a surface (See contour) isoline framework p. 30 a measurement framework that establishes control by a systematic set of slices through an attribute to obtain lines that represent the surface. J ...
Contour Line:
A line on a map that traces locations where the value of a variable is constant. For example, contour lines of elevation trace points of equal elevation across the map.
The map on the right depicts yet another procedure for assigning contour breaks. This approach divides the data into groups based on the calculated mean and Standard Deviation.
Elevation contours may be generated and output as an ArcView shapefile.
Additional data layers are available to assist in defining spatial bounds.
Zoom in map control allows "rubber-band" zooming.
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.
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.
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.
One example of highly specialized GIS work at ORNL was Ed Ti nnel's development, in cooperation with Bill Hinze of Purdue University , of spatial filtering, interpolation, and contouring techniques to convert one-dimensional flight line data into ...
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.
by scanning the contour overlays for all 1:250,000-scale topographic maps. From the scanned contour lines, elevations were sampled every 3 arc-seconds of latitude and longitude (approximately every 90 m).
Topographic maps (Figure 2.4) show the shape of the earth’s surface by contour (elevation) lines.
Such a map can be thought of as a rainfall contour map. Many sophisticated methods can estimate the characteristics of surfaces from a limited number of point measurements.
When there is little detail available, make a rough contour sketch. Use only standard topographic and military symbols on the sketches.
Scope and scale.
especially during Middle Ages, most maps intended only illustrating the Earth features, thus lacking precise contours and, frequently, a graticule ...
contours, street centerlines, or streams), or linear features with no area (e.g., state and county boundary lines).
2. A single arc in a coverage.
3. A line on a map (e.g., a neatline).
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.
Reopen the Geoprocessing wizard and merge this theme with your point theme you've created for all your contour lines.
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.
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.
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.
 See also: Information, Map, Area, Geographic, Surface
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