Instituto Brasileiro de Geografia e Estatística

About the publication - Cartographic dictionary

A

Acceleration of gravity
Force resulting from the gravitational attraction of the mass of Earth and the centrifugal force of its rotation, exerted on a mass element. It varies according to the position on the surface, due to rotation, topography and variations in the internal density of Earth.

Aerophotogrammetric surveying
Method of photographic surveying that uses a photogrammetric camera as a sensor, installed in aircraft, to photograph the area of interest in a systematic way, forming strips of aerial photographs with specifications that allow the construction of stereoscopic models.

Aerophotogrammetry
See Photogrammetry

Alluvium
Generic name to encompass recent landfill sites, either of river or lake nature, comprising gravel, sand, silt and clay, transported and deposited by streams in flood plains and in the foothill of many cliffs.

Altimetry
Set of processes aiming at determining the altitude of a specific geodetic station

Altitude
Vertical distance from a referential, usually the average sea level, to the point concerned. The altitudes obtained from the screening of artificial satellites have an ellipsoid as reference, therefore geometric.

Area
Amount projected in a horizontal plan inside the limits of a polygon. It is every aggregate of flat spaces to be considered in a study or survey.

B

Basic or systematic mapping
Set of regular mapping operations destined to the edition of charts for the systematic coverage of a country or region, from which other charts or maps can derive upon.

Border
Line, either materialized or not, that demarcates the frontier between two neighbor areas. It is usually established by law of any instance of the public administration, federal, state or municipal.

Borderline
Dividing line between territorial units or areas.

Brazilian Fundamental Gravimetric Network
Gravimetric datum of the Brazilian Geodetic System connected to the International Gravity Standardization Net, 1971 and to absolute gravimetric stations in the national territory.


C

Cartogram
Representative scheme of a surface or part thereof, on which quantitative and qualitative information on geographic, cartographic and socioeconomic events are shown.

Cartographic representation
Graphic representation of a surface, following pre-established cartographic conventions and rules, either general or partial, in two or three dimensions (Earth, Planet, Moon, Sky, etc.).

Cartographic Scale
Mathematical relation between the dimensions of the elements in the design and in the terrain.

Cartographic System
Set of specifications that regulate the organization of a coherent group of charts of a country or region.

Cartography
Set of studies and scientific, technical and artistic operations based on the results of direct observations or on the analysis of the existing documentation, aiming at the creation of maps, charts and other forms of graphic expression or representation of objects, elements, phenomena, and physical and socioeconomic environments, as well as their use

Chart
Representation of a portion of the Earth´s surface on a plan, usually in medium or large scale, destined to a number of uses, like, for example, the precise assessment of distances, directions and geographic location of natural and artificial aspects. It can be subdivided into sheets in a systematic way, according to a national or international plan.

CONCAR
National Commission of Cartography, subordinate to the federal administration, comprises the entities of the National Cartographic System - SCN, whose major role is to coordinate the development of the National Cartographic Policy.


D

Dam
Small reservoir of natural or artificial water.

Datum
System of reference for the geodetic coordinates and acceleration of gravity. In the case of planimetry, the datum of the Brazilian Geodetic System is the South American Datum - SAD-69; for altimetry, Imbituba; for gravimetry, the Brazilian Fundamental Gravity Network.

Downstream
Stretch of a water course located below a reference point.


E

East
One of the cardinal points, the same as rising sun. - Cardinal Point located to the right of the observer facing North, Orient, Rising Sun or Raising Sun.

East
Side where the sun rises, Rising sun, Raising sun.

Eastern
Related to the east.

EG
See Gravimetric station

Ellipsoid
Mathematical figure most suitable for representing the Earth form, due to the simplification of the calculations and good relative resemblance to its real form. See also Geoid.

EP
See Polygonal station


F

Photogrammetry
(General) science that deals with the acquisition of reliable measurements of photographic images.- (Mapping)science that produces topographic charts, comprising a number of mathematical and physical methods and processes from aerial or orbital images or photographs, using sophisticated optical-mechanical instruments.



G

Geodetic station
Point of the terrestrial surface, physically defined as a milestone, plate or pin, located in a solid and stable terrain, whose geodetic coordinates and gravity acceleration were established through appropriate geodetic surveys. Geodetic stations are protected by law, due to their importance and high cost of localization.

Geographic coordinates
Numeric values through which a position of a point in the Earth´s surface can be defined, having the Ecuador as the point of origin for the latitudes and the Greenwich Meridian, for the longitudes.

Geoid
Figure defined as an equipotential surface of the gravity field of Earth that closely resembles the average sea level, supposedly homogeneous and static. Although it best describes the physical form of Earth, the geoid is characterized by a great complexity, due to the irregular distribution of the masses in the interior of Earth and, therefore, by a difficult mathematical representation, which leads to the adoption of the ellipsoid as the mathematical form of Earth, due to the simplification of its use.

Geoid Height
Distance between the reference ellipsoid and the geoid, counted on the normal to the ellipsoid passing through the point.

Geoid map
Media through which the height or geoid undulation can be approximately obtained in a given geodetic station.

Geoid undulation
See Geoid height

Graphic Scale
Graphic representation of the numeric scale under the form of a string line, in which the relation between the real distances and those represented on the maps, charts or other cartographic documents is given by a line segment in which a unity measured in the line corresponds to a given real measurement.

Gravimetric station
Geodetic station mainly aimed at gravity acceleration.

Gravimetry
Set of processes aiming at determining the acceleration of gravity in a given geodetic station.

Greenwich
Name of the British city, located in the east of London, where the Royal Observatory was built and where is the meridian that originates the longitudes since 1884.


H

Height
Vertical distance between a point and a reference plan, which is usually the Earth´s surface.


I

IGSN-71
See International Gravity Standardization Net, 1971

Imbituba
Vertical datum of the Brazilian Geodetic System, defined by the average sea level in the Port of Imbituba (SC). See also Tide gauge station.

Index map
Cartogram that contains information on the cartographic coverage of a country in the different scales of the systematic mapping.

International Gravity Standardization Net, 1971
World gravimetric network of reference, aimed at ensuring the homogeneity of the gravimetric determinations across the Earth.

International Union of Geodesy and Geophysics, 1967
Ellipsoid used in the South American Datum, 1969, recommended in the General Assembly of the International Union of Geodesy and Geophysics of 1967.

IUGG-67
See International Union of Geodesy and Geophysics, 1967


L

Laplace
Planimetric geodetic station determined through high-precision astronomical observations.

Latitude
Angle formed by the normal to the surface adopted for Earth, which passes through the point concerned and the stretch corresponding to its projection on the Ecuador´s Plan. Whenever measured towards the North Pole, the latitude is called North or Positive Latitude. Whenever measured towards the South Pole, it is called South or Negative Latitude. Its variation is:
O° to 9O°N or O° to + 90°
O° to 9O°S or O° to - 90°

Level reference
Altimetric geodetic station established through a high-precision geometric leveling.

Longitude
Dihedral angle formed by the plans of the Greenwich Meridian and the meridian that passes through the point concerned. The longitude can be counted westwards, when it is called West of Greenwich (W Gr.) or Negative Longitude. If counted eastwards, it is called East of Greenwich (E Gr.) or Positive Longitude.


M

Map
Representation on the plan, usually in small scale, of the geographic, natural, cultural and artificial aspects of all the surface (Planisphere or World Map), of a part of it (Maps of the Continents), of a surface defined by a given political-administrative division (Map of Brazil, States or Municipalities) or of a given operational or sectoral division (river basins, areas of environmental protection, enumeration areas).


Mapping
Set of geodetic, photogrammetric, cartographic and remote sensing operations aiming at the edition of one or several types of charts and maps of any nature, like basic or derivative, registry, topographic, geographic, especial, thematic charts, etc.





Meridian
North-south reference line, particularly the maximum circle through the geographic poles of Earth, from which the longitudes and azimuths are established. They are maximum circles that split the Earth into two equal parts from pole to pole, causing all the meridians to cross with each other, in both poles. The origin meridian is that of GREENWICH (0°)

Meridional
Related to the South, the same as austral.


N

National Cartographic System
Comprises national entities, either public or private. Comprises all the cartographic activities in the entire national territory, according to Decree-Law no. 243. Brazilian Geodetic System - set of geodetic points deployed in the terrestrial surface within the Brazilian boundaries, established by operational procedures and calculated coordinates, according to precise geodetic models compatible with the objectives they are destined.

Northern
Related to the North, Boreal

Numeric Scale
Scale of a cartographic document – map, chart or plan – expressed as a fraction or proportion, which correlates the unity of distance of the document with the distance measured in the same unity in the terrain.
Example: 1:100,000 - Read 1 by 100,000.

Means that 1 cm in the document amounts to 100,000 cm in the terrain, i.e., 1,000 m or 1 km.
Whenever the numeric scale is known, the real distances can be calculated through the expressions:
D = d x N \ N = D / d \ d = D / N

D = Real distance
d = Distance in the document
E = Scale = 1 / N

What will be the dimension in the terrain of a 15-cm element on the cartographic document created in the 1:50,000 scale?

E = 1/ 50,000 = 1/N

d = 15

D = d x N

D = 15 x 50,000 = 750,000 = 7.5 km

A 7.5-km element in the terrain will be represented on a cartographic document in the 1:50,000 scale with what dimension?

E= 1 / N = 1 / 50,000

D = 7.5 km = 7,500 m = 750,000 cm

d= D / N = 750,000 / 50,000 = 15 cm

What is the scale of a cartographic document in which a 7.5-km element in the terrain is represented by 15 cm?

D = 7.5 Km = 750,000 cm
d = 15 cm
N= D/d = 750,000 / 15 = 50,000


E = 1 / N = 1 / 50,000
soil surface.

O

Occident
The west side of reference.

P

Parallels
Circles of the Earth surface parallel to the Ecuador plan, which link all the points of the same latitude.
Circles that cross the meridians perpendicularly, i.e., in right angles. Only one is a maximum circle, the Ecuador (0°). The others, both in the North hemisphere and South hemisphere, decrease their sizes as they move away from the Ecuador until they become a point (90°) in each pole.

Planimetry
Set of processes aiming at establishing the horizontal geodetic coordinates of a given geodetic station.

Polygonal station
Planimetric geodetic station determined through the method of geodetic polygonation.

R

RGFB
See Brazilian Fundamental Gravimetric Network

RN
See Level reference

S

SAD-69
See South American Datum, 1969

Sandbank
Accumulation of silt – sand and gravel – deposited in a riverbed, acting as an obstacle for drainage and navigation.

SAT
See Satellite station

Satellite station
Three-dimensional geodetic station determined through tracking techniques of artificial satellites.

Scale
Relation between the dimensions of the elements represented on a map, chart, photograph or image and the corresponding dimensions in the terrain.

South American Datum, 1969
Horizontal datum of the Brazilian Geodetic System, defined in the Chuá Triangulation Vertex (MG), oriented to the Uberaba Triangulation Vertex (MG), having the ellipsoid recommended by the International Union of Geodesy and Geophysics, 1967 as the reference surface.

Stereoscope
Instrument destined to the  examination of pairs of photographs or images seen from different points, resulting in a mental impression of a three-dimensional vision. Lenses, mirrors and prisms are used to build it.

Stereoscopy
Optical illusion produced whenever documents are observed with appropriate lenses, under a certain condition of area overlap, providing a sensation of three-dimensionality.
Science that deals with three-dimensional models and the methods through which this effect is produced.

T

Tide gauge station
Set of instruments and installations aimed at the observation of sea level. Geodesy uses tide gauge stations to establish the average sea level.

Time zone
Established convention related to an area within two meridians, in which time is the same for all the locations inside it. Each zone usually has 15° of longitude, centered by a meridian whose longitude is exactly divided by 15.

W

Waterway
Navigable stretch of a water course or channel.

West
Cardinal point located to the left of the observer facing North.

Western
Related to the west