|
 |
 |
 |
Glossary Search Results
T |
- Tag
- An identification label, code, or classification symbol for each cell in a GIS; stored as an "x,y" coordinate. (Also called a label point).
- Tangent
- A mathematical term used in the construction of some geometric map projections describing a straight line or plane surface touching a curved line or curved surface at a single point but not intersecting it.
- Tectonic
- Related to the study of terrain deformations caused by internal forces, after the setting of the rocks.
- Tectonic plate
- Broad thick plate composed of areas of both continental and oceanic crust and mantle. (Source: The Encyclopaedic Dictionary of Physical Geography, edited by Andrew Goudie et al. Blackwell Reference Ltd. Oxford, 1985.)
- Telluric
- Pertaining to the Earth
- Telluric currents
- Static or alternating electric current flowing through the ground and arising either in natural or artificial electric or magnetic fields. (Glossary of geology. Margaret Gary, Robert McAfee, Jr., and Carol L. Wolf, editors; Washington: American Geological Institute, 1972.)
- Temperate forest
- One of the three main forest types in the world. Temperate forests are composed mainly of deciduous trees. The other two types are the tropical evergreen forest and the northern coniferous forest (boreal forest).
- Template
- In traditional cartography, a thin sheet of plastic or metal with symbols or lettering cut out, used as a guide for drawing, painting, or scribing the corresponding pattern on a map. (Also called a stencil). In the digital environment templates are often used for maps, attribute tables and documents having a standard format.
- Tenure
- Refers to whether some member of the household owns or rents the dwelling, or whether the dwelling is Band housing (on an Indian Reserve or settlement). A dwelling is classified as “owned” even if it is not fully paid for, such as one which has a mortgage or some other claim on it. A dwelling is classified as “rented” even if it is provided without cash rent or a reduced rent or if the dwelling is part of a cooperative. (Source: Statistics Canada)
- Tephra
- The solid material ejected from a volcano which includes dust, ash, cinders and volcanic bombs. (Source: The Encyclopaedic Dictionary of Physical Geography, edited by Andrew Goudie et al. Blackwell Reference Ltd. Oxford, 1985.)
- Tertiary
- Third era of the geologic time which began about 65 million years ago and lasted 63 millions years.
- Thematic map
- A class of map showing the spatial distribution of a particular phenomenon in qualitative or quantitative graphic form. The opposite of a base or reference map (which shows only fundamental information about the Earth's surface and are used as a locational reference base for thematic data). Almost any subject that can be expressed as a geographical distribution can be mapped. Examples of thematic map subjects include population, precipitation, vegetation, exploration, and employment.
- Theodolite
- A survey instrument consisting of an alidade, telescope, and vertically and horizontally mounted graduated circles, used to measure vertical and horizontal angles. (See Alidade and Transit).
- Thermal generating stations
- These stations are powered by burning a fuel (or else using waste heat). The Statistics Canada database classifies thermal plants into three types of technology: steam, internal combustion, and combustion turbine. Strictly speaking, nuclear plants are thermal plants, but general usage puts nuclear as a separate category
- Thermokarst
- Karst-like topographic feature produced in a permafrost region by the local melting of ground ice and the subsequent settling of the ground.
- till
- any sediment that is transported and deposited by a glacier without being sorted by meltwater. It consists of clay, sand and large rock fragments that are deposited in irregular sheets or in ridges called moraines.
- Timber licenses
- A license to cut and remove Crown timber.
- Time zone
- A geographical region in which the time used is the same everywhere within that region. Sir Sandford Fleming, Canadian railway surveyor and construction engineer, advocated the establishment of an international system of standard time zones and was instrumental in convening an International Prime Meridian Conference in Washington, in 1884. At this meeting, 24 World standard time zones with a time spacing of one hour were defined. Each zone is 15° of longitude in width, centred on standard meridians 15° apart and referenced to the Greenwich Meridian. Additional time zones have been introduced some using divisions of 7° 30' longitude and a time spacing of one half hour difference from adjacent zones (e.g., Newfoundland Standard Time). Due to political, socio-economic, or physiographic realities, most time zone boundaries have been displaced considerably. Each country is responsible for the designation and location of time zones within its own boundaries.
- Tint
- (1) The variation in colour that occurs when a pure hue of colour is combined with white, having the effect of increasing brightness but lowering saturation or intensity. In printing this effect is achieved by using half-tone or percentage screens which allow an amount of white paper to be exposed around the small dots or lines of solid hue. (See Colour and Hue).
(2) One of a sequence of graduated bands or shades of colour (often bounded by contour lines) used to depict a range of elevations on a map. (See Hypsometric tints).
- Tolerance
- A statement of the allowable deviation from a specified standard or condition. (See Accuracy, map and Standards).
- Tone
- The variation in colour that occurs when white, a pure hue of colour, or tint is combined with black or a percentage of black, having the effect of decreasing brightness and saturation. In printing this effect is achieved by adding a half-tone or percentage screen of black or grey on top of the colour, at a correct screen angle. (See Colour and Tint).
- Topographic map
- A class of map designed primarily for the purpose of depicting elevation (relief), as opposed to a planimetric map which only shows the horizontal location of geographic features. Topographic maps show vertical data with contour lines, hypsometric tints, spot heights, and relief shading. Also shown is fundamental information about the Earth's surface such as landforms, vegetation, and drainage. Cultural and landmark features, such as roads, railways, populated places, and buildings are often included. Topographic maps are usually available as a series, such as the 1:50 000 and 1:250 000 scale National Topographic System (NTS) maps, produced by the Centre for Topographic Information, Geomatics Canada, Natural Resources Canada.
- Topography
- The configuration or shape of features on the Earth's land surface. Topography is depicted on maps by contour lines, hypsometric tints, and relief shading. Also called landforms and relief. In oceanography this term refers to the characteristics of shape and surface of the ocean bottom, (or the bottom of other water bodies). (See Topographic map).
- Topology
- The spatial relationships between point, line, and area features of a data set, expressed and stored as connections between touching lines, small areas within larger ones, the sides of polygons shared by adjacent polygons and so on. Topologic relationships are useful in GIS because many spatial analysis operations do not require coordinates, only topological information. For example, to find the best path between two points requires a list of lines that connect to each other. Coordinates are only needed to draw the path once it is calculated.
- Toponym
- The name of a geographic feature or populated place shown on a map. Also called a geographical name.
- Toponymy
- The branch of geography and cartography that deals with the naming of populated places, natural, and man-made geographical features on maps. In Canada the authority for geographical names lies with the provinces and territories. The Geographical Names Board of Canada (GNBC) coordinates this effort, and stimulates the development and adoption of standard policies within Canada for the handling of names and terminology. GNBC also encourages the development of international standards in cooperation with the United Nations and other national authorities responsible for naming policies and practices. The GNBC is served by a Secretariat provided by the Centre for Topographic Information, Geomatics Canada, Earth Sciences Sector, Department of Natural Resources Canada.
- Total Income
- This represents the sum of market income and government transfers. (Source: 1996 Census Dictionary, Cat. No. 92-351-XPE, Statistics Canada)
- Township
- (1) A geographical division within a public land survey system that is defined by a square parcel of land bounded on the east and west by meridians 6 miles apart and by parallels to the north and south also 6 miles apart. This 36 square mile unit of land contains 36 sections, each being one square mile.
(2) A township can also be a governmental subdivision, which may vary from the standard size and shape. (See Land survey systems, Lot and Range).
- Traditional cartography
- (See Cartography)
- Trafficability
- Capability of terrain to bear traffic. It refers to the extent to which the terrain will permit continued movement of any or all types of traffic. Source: McGraw-Hill Dictionary of Scientific and Technical Terms, Lapedes, D.N. (ed.). : McGraw-Hill, New York, Montréal, 1976.
- Transformer
- A device used for stepping voltage or current up or down, for power transfer; also for isolation of the primary circuit from the secondary circuit. (Glossary of plant & process terms. Atomic Energy of Canada Limited, Ottawa, Atomic Energy of Canada, 1974)
- Transit
- A survey instrument similar to a theodolite except that the telescope can be reversed by rotating it about its horizontal axis. (See Theodolite).
- Transitional forest
- A mixture of land covers, with forest covering up to 50 percent of the land area. Tree density varies from open woodland to scattered groves.
- Transparency
- The ability of a material to transmit light.
- Transparency (photo)
- A positive photographic image on a clear base (plastic or glass) that may be viewed using a slide or overhead projector and used in a stereoscopic plotter. (Also called a diapositive or slide).
- Traverse
- A horizontal survey involving a connected series of straight lines between points of known location. The locations have been determined by measuring the direction (angle), and distance from the preceding point in the sequence.
- Treaty Indians
- Treaty Indians are descendants of Indians who signed treaties with Canada and who have a contemporary connection with a treaty band. (Source: Department of Indian Affairs and Northern Development)
- Tree harvesting
- A harvesting process that includes the trunk, branches and, in some instances, the roots from a forest site. In Canada, this process is used to control root diseases.
- Treeline
- The northern limit of trees beyond which conditions do not permit their growth.
- Triangulation
- An accurate method of surveying based on the geometric principle that if the measurements of one side and two angles of a triangle are known then the other dimensions of the triangle can be calculated. Starting with a known base line, a network of known horizontal positions on the Earth's surface may be established by expanding a network of triangles, for once the other sides of the first triangle are calculated then one of them can be used as the base line for the next triangle. This process establishes horizontal control.
- Tropic of Cancer
- The latitude of 23° 27' north, at which point the Sun reaches its greatest northerly declination (or summer solstice, for the Northern Hemisphere). This occurs on or about June 21, marking the start of summer and the day of the year having the longest period of daylight in the Northern Hemisphere. Also, the complement of latitude 66° 33' north, being the Arctic Circle. The region lying between the two Tropics is known as the Torrid Zone. (See Tropic of Capricorn).
- Tropic of Capricorn
- The latitude of 23° 27' south, at which point the Sun reaches its greatest southerly declination (or winter solstice, for the Northern Hemisphere). This occurs on or about December 21, marking the start of winter and the day of the year having the shortest period of daylight in the Northern Hemisphere. Also, the complement of latitude 66° 33' south, being the Antarctic Circle. The region lying between the two Tropics is known as the Torrid Zone. (See Tropic of Cancer).
- Tundra
- The treeless area to the north of the boreal forest. Tundra vegetation includes low, matted and erect shrubs and herbs such as cottongrass.
- Type affixing
- In traditional cartography, the attachment of type in the form of stripping film on to a registered map overlay in proper relationship to linework and other map symbology. An adhesive, usually a coating of wax is applied to the emulsion side of a wrong reading image positive stripping film. A sharp but delicate knife is used to cut around the type image and using a pair of tweezers, the thin emulsion layer is peeled off and positioned on a clear map overlay. Finally, by using a burnishing tool, the thin emulsion layer containing the type image and coated with wax, is rubbed down thereby ensuring better adhesion. The same process may be done using negative stripping film and a map negative overlay. (See Stripping film).
- Typography
- The art of typesetting, including the style, appearance, printing and the use of type. In cartography the basic methods of type production are: hand lettering, stencilled lettering (e.g. Rapidograph and Leroy), preprinted lettering (e.g. Letraset), mechanical or optical type setting equipment (e.g. Linotype and Linofilm), and type produced digitally or stored as a graphic element in an automated cartographic system (e.g. Compugraphic and ARC/INFO annotation). Type is used extensively on maps to identify a variety of geographical features, therefore, the choice and placement of type requires important consideration. Effectively used type is essential for good communication by a map.
|
|
|
Select the first letter
of the word you are looking for |
|
A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
K |
L |
M |
N |
O |
P |
Q |
R |
S |
T |
U |
V |
W |
X |
Y |
Z
|
|
|
|
