sans-serif type
A class or style of type in which individual letters are simple in design and have no serifs (short crosslines or ticks) at the ends of the letter strokes. The type fonts Helvetica, Triumvirate, News Gothic, and Futura are examples of this style.
satellite imagery
A type of remotely sensed imagery of the Earth's surface which is produced from data gathered by an orbiting satellite and processed by an Earth receiving station. Several forms of imagery are available based on different technologies: optical, near-infrared, thermal infrared (heat), and microwave (radar). Satellite imagery has many applications including small scale base and thematic mapping, weather forcasting, environmental studies, and military use. Examples of Earth observation satellites are: RADARSAT, LANDSAT, NOAA, SPOT, and ERS. (See remote sensing).
scale (see map
scale)
scanner
A peripheral computer hardware device used to input data in raster format. There are two types of scanners, one type systematically examines every element of a map manuscript, diagram, or image by directing a light beam in a succession of linear sweeps accross the original copy. Data about each element ("x,y" coordinates and spectral signature), are recorded in digital form (raster format) on computer tape which can be later edited and used as a digital file.
The other type of scanner (commonly used on Earth observation satellites for
the production of remotely sensed imagery), records the radiation being
reflected from the Earth's surface. This data is processed in a manner similar
to the first type mentioned. Scanners often have software which allows them to
convert raster format data to vector format. (See drum scanner).
scanning
The process of electronically examining and recording the data elements of a map or image sequentially, instead of viewing the entire image at one time. (See scanner and drum scanner ).
screen (see dot
screen)
scribing
A cartographic drafting procedure in traditional cartography involving the production of artificial line negatives by using an engraving instrument to cut and remove the semi-opaque surface coating of a scribing media. Scribing instruments hold either a needle or chisel pointed tool made of steel, carbide, or sapphire. These points, which are available in different line widths, are used to cut lines, symbols, and polygon outlines. Scribing media (also called scribe coat) consists of a clear stable plastic base (polyester) covered with a semi-opaque coating (usually orange in colour). Special bevelled templates are often used in the process to scribe pre-set symbols or line patterns.
sea level
The surface elevation of the oceans at a given time. (See mean sea level).
secant
A straight line that cuts a curve or surface at two or more points. Secants are used in the construction of some geometric map projections.
second
(1) A unit of angular measurement equal to 1/60 of an angular minute. There are 3600 seconds in one degree of a circle. (2) A unit of time, equal to 1/60 of a minute of time.
section
In a public land survey system, a subdivision 1/36 of a township equal to one square mile or 640 acres and having boundaries conforming to meridians and parallels.
serif type
A class or style of type in which individual letters are somewhat ornate in design and have serifs (short crosslines or ticks) at the ends of the letter strokes. The type fonts Times Roman, Century Schoolbook, and Palatino are examples of this style.
sextant
A hand-held instrument used for navigation and surveying when it is not convenient to use a theodolite or transit. A sextant is used to measure the angle at the point of observation between a celestial object and the horizon, or between two objects. The angle is measured on a graduated arc covering 1/6 of a full circle or 60 °, hence the name "sextant".
shoreline
A line on a map representing the transition between an area of land and a body of water. A shoreline can delineate a polygon representing a lake or indicate the intersection between a landmass and an ocean.
slope
An angle of inclination from the horizontal, appearing as a tilted plane of land. Slope may be expressed as a numerical ratio, percentage, or in degrees. Slope is represented on maps by contour lines, relief shading and hachures; the closer together the contour lines, the steeper the slope.
small scale map
A small-scale map provides coverage of a larger area of the Earth than a large-scale map. There is no universally accepted map scale dividing large-scale from small-scale maps. However, a map at a scale of 1:500 000 or smaller is considered a small-scale map. Regional and World maps fall into this category. (See large scale map and medium scale map).
South Pole
The geographical location at 90°S latitude in the southern hemisphere where the Earth's axis of rotation intersects the surface of the Earth.
spatial analysis
The study of spatial relationships between geographic features by using the processes of modeling, examination and interpreting, for the purpose of evaluating, estimating, predicting and understanding these relationships. Available methods in a GIS for spatial analysis include overlay operations, classification, measurement, network display, and proximity structure.
spatial data
Data, usually stored as coordinates, that describe the location, shape, and spatial relationships of geographic features.
spatial modelling
In GIS technology, a method of analyzing spatial data, based on a specific set of rules used to derive new information for problem solving or planning. There are three forms of spatial modelling, each having different methods of operation: geometric models calculate measurements, coincidence models use overlay operations to reveal new relationships, and adjacency models identify contiguous areas.
specifications ("specs")
A set of detailed instructions used to describe the layout, content, and procedures involved in the production of a map. Specifications may be in text form and contain graphic representations of map symbology, along with measurements, colours and screen percentages.
spheroid
A 3-dimensional geometric shape based on an ellipse that represents the Earth and approximates the size and shape of the geoid. When mathematically defined it may be used as a datum (surface reference) for geodetic surveys. For example, the North American Datum 1983 (NAD 83) is a spheroid. (See datum and geoid).
spot height
An isolated dot or cross symbol on a map, (separate from contour lines) indicating a point on the ground of known surveyed elevation and labelled with an elevation value. For inland bodies of water, elevation is indicated by a surface elevation value. Spot heights usually indicate elevations above or below mean sea level based on a specified datum. (Also called spot elevations). (See contour line and elevation).
stability, material
In traditional cartography, the ability of map production or reproduction material to retain its original dimensions and resist shrinkage or expansion when subjected to changes in temperature or humidity. Material stability is an important factor influencing the accurate registration of map production materials. To avoid misregistration, all materials involved in the production of a map must be prepared and stored under the same atmospheric environmental conditions. Photographic materials, particularly those cut from a roll, should be laid out flat and conditioned before use. Also, a printing press run should be completed at one time and not continued over several days so as to avoid changes in paper size (due to humidity, etc.).
standard parallel
The line of latitude in a cylindrical or conic map projection where the surface of the projection either touches or intersects the globe. If contact with the globe is secant, the result is two standard parallels. These lines of latitude are significant since they define lines of zero distortion, along which there is true linear scale. Standard parallels are also referred to as standard lines.
standards
A fixed set of procedures and workmanship guidelines which are established and defined by authority, convention, or market demand. These objectives serve as a reference, model, or scale used to measure product or service quality and quantity, and to evaluate results. For digital mapping, there are standards set by the International Standards Organization (ISO); for maps intended for military use, there are North Atlantic Treaty Organization (NATO) standards.
statute mile
A unit of distance in the British system of measurement defined by law to be exactly 5 280 feet or approximately 1.60935 kilometres.
stereographic map projection
A planar map projection which is tangent to the globe at a single point, but may be oriented at any aspect. The projection views the Earth's surface from the point on the globe opposite the point of tangency. In the polar case, parallels are represented by a system of concentric circles sharing a common point of origin from which radiate the meridians, spaced at true angles. This projection shows true direction, but only between its centre and other locations on the same map, and is the only planar map projection that is conformal.
stereoplotter
A photogrammetric plotter with two or more projectors (multiplex) used to project a stereoscopic image (called a model) from aerial photograph transparencies (called diapositives). Measurements are then taken from the model and traced out (as contour lines) on a manuscript, thereby providing an accurate topographic representation of an area. A stereoplotter is also used to trace out roads and plot land marks and other cultural and physical features in their correct relative positions. (See contour lines, culture, photogrammetry and stereoplotting).
stereoplotting
The process of using a stereoplotter to record and convert measurements made from a stereoscopic model into a drawing or map. A stereoscopic model or hologram is a 3-dimensional optical image produced by combining the images from two overlapping aerial photographs, or other remotely sensed imagery (taken at slightly different angles) of the same area. A stereoplotter uses automated photogrammetric techniques to plot contour lines and geographic features from a stereoscopic model on to map using a coordinate system. (See photogrammetry and stereoplotter).
stripping film
A high contrast photographic film having a thin peelable layer, designed primarily for photomechanical reproduction in order to produce sharp high density images. Stripping film is used in traditional cartography for type and symbol affixing. After exposure and development, the thin emulsion layer carrying the image may be peeled away from the film base. Usually a wax coating is applied to the emulsion layer allowing it to be affixed to a positive map overlay, or a negative. Stripping film may be either positve or negative, and reverse or right reading.
surround
The area of a map outside the neat line. On a topographic map the surround usually contains the border, title, index number, scale, UTM grid zone designation, magnetic declination and production notes.
The orderly process of making and recording measurements of distance, direction, angle, and elevation to determine the relative location of points on, above, or beneath the Earth's surface. There are a number of types of surveys done to obtain data for mapping: geodetic, phototriangulation, hydrographic, cadastral, and field. (See land survey systems).
symbols
The graphic elements shown on a map designed to represent geographic features or communicate a message, at a given scale. There are three basic forms of map symbology: point, line, and area. Map symbols may represent qualitative data and be shown as a distribution, or they can express quantitative data by showing proportionality or ratio. Map symbols are usually explained in a legend.