Join now. The north-south scale, called latitude, ranges from +90° (or 90° N) at the North pole to -90° (or 90° S) at the South pole. Representative Fraction (RF): Scale can be expressed as a ratio or representative fraction (RF). • Divide the first part A0 into 10 equal … The fraction 1/100 is a much much smaller number than is 1/2. Kindly provide the complete solution of above question. Balancing extent and resolution is often one of the most important and difficult decisions a cartographer must make. Areal measurement most often is from map units to ground units. Log in. We can also Some projections, including the Robinson projection, strike a balance between the different map properties. To find the actual distance you first measure the distance between the two points on the map and then you compare that measurement with the map scale. The earth’s surface has an area of over 500 million km2 and any picture of the earth that you can easily carry can only show general outlines of continents and countries. The Gall Peters projection is equal area.        means that: One inch on the map is equal to 24000 inches on the surface of the 2. Opposite the International Date Line is the prime meridian, the line of longitude defined as 0°. The properties we will focus on are shape, area, and distance. It simply means that 1 unit on the mapis to 100,000 unitson the earth's surface. We often choose mapping resolutions intentionally to make the map easier to understand. The relationship between ground and map distance can be expressed by either a linear or aerial measurement. Flattened orange peel. We can also Gall-Peters projection. RF Group Leader; RF Group Name; RF Group Leader. 1:50000 can be shown as 1/50000 as well. to twenty thousand". [6]. Rf … 8 : CONSTRUCTION:A motor car is running at a speed of 60 kph. In simple terms, longitude specifies positions east and west and latitude specifies positions north and south. The flag of the United Nations contains an example of a polar azimuthal equidistant projection. Airphoto Interpretation, fifth edition. Graphic Scale to RF. New York: John Wiley & Sons. Of these three problems, tearing is seen as the worst because you would be making maps with all sorts of holes in them! One inch is equal to three miles (1" = 3 miles) Graphic Scale: The simplest graphic scale is a bar scale. Scale bars are graphical representations of distance on a map. The place where the developable surface touches the globe is known as the tangent point or tangent line. The projection was developed in 1923 by John Paul Goode to provide an alternative to the Mercator projection for portraying global areal relationships. For beginning mapmakers, understanding the exact mechanics of projections doesn’t matter as much as knowing which map properties are maintained or lost with the choice of projection – the topic of the next section. Full Scale When an object is drawn on the sheet to its actual size, it is said to be drawn to full scale. The first we will consider is the RF or Representative Fraction. Temperature scales like Celsius (C) and Fahrenheit (F) are measured by using the interval scale. The Language of Maps, Pathway in Geography series. If you had a clear globe the size of a beach ball and placed a light inside this globe, it would cast shadows onto a surrounding surface. How many cm to the km. It is always equal to 1 The denominator represents ground distance in the same units as the numerator. Here we must take a measurement from the bar scale to determine the map distance that corresponds to a ground distance. Obviously, for full scale, RF = 1. These help us to visualize what type of distortion a map projection has caused, how much distortion has occurred, and where it has occurred. 3. 8 : CONSTRUCTION:A motor car is running at a speed of 60 kph. A map of an area 100 miles long by 100 miles wide drawn at a scale of 1:63,360 would be more than 8 When a map is enlarged or reduced, the bar scale changes size in direct proportion to the map. ∠oa ∠PA 60000' 1' 60000' 12" = = = H f s Scale of a Vertical Aerial Photograph Over Variable Terrain h is the measurement of the elevation of a point above the sea level and the H is the altitude above sea level. expressed by a graphic scale such as a circle or square of a proportionate size. Compromise projections preserve no one property but instead seek a compromise that minimizes distortion of all kinds, as with the Robinson projection, which is often used for small-scale thematic maps of the world. Views drawn by free-hand or with drawing instruments such as plastic foot scales are to be accepted. Maps can have an enormous array of different coordinate systems depending on who developed and used them. Converting Between Scale Types of Historic and Modern Maps, page 3 Converting Representative Fraction (RF)/Ratio Scale to Lexical Scale English and Metric Measures of Length to use:. Projections must distort features on the surface of the globe during the process of making them flat because projection involves shearing, tearing, and compression. Equidistant projections, as the name suggests, preserve distance. This type of projection would be useful visualizing airplane flight paths from one city to several other cities or in mapping an earthquake epicenter. Interpreting the readings can be confusing as there are multiple units of measurement. Safe Living Technologies Inc. has created a RF unit conversion table and EMF unit conversion table: 1991, 1996. Projections deal with the methods and challenges around turning a three-dimensional (and sort of lumpy) earth into a two-dimensional map. Verbal map scale: A map scale that expresses the relationship between distance on the map and distance on the ground in words; for example, "One inch equals 10 miles." 2 weighings to find the slightly heavier ball. The world is vast. Characteristics Of a Good Scale are: They are very useful for navigation, topography (elevation), and weather maps. Mercator distortion. The representative fraction is accurate regardless of which units are used; the RF can be measured as 1 centimeter to 24,000 centimeters, one inch to 24,000 inches, or any other unit. Starting in the 7.0.116.0 release, the RF Group Leader can be configured in two ways as follows: . Secondary School. Map makers use the term scale to describe maps as being small-scale or large-scale. 1:60,000. ; RF = 1: 20,000 RF = 1 500 Case 2: RF will be given not directly, Possible ways of giving RF. The most commonly used measure of map scale is the representative fraction (RF), where map scale is shown as a ratio. It can be expressed as 1/100,000 or 1:100,000. Because the Earth is round, +180° (or 180° E) and -180° (or 180° W) are the same grid line, termed the International Date Line. Be the first to answer this Question ! The simplest graphic scale is a bar scale. Start studying music88nat. 3. Put differently, if we were to change the scale of the map with an RF of 1:100,000 so that a section of road was reduced from one unit to, say, 0.1 units in length, we would have created a smaller-scale map whose representative fraction is 1:1,000,000. The numerator, which is always set to one (i.e., 1), denotes map distance and the denominator denotes ground or “real-world” distance. Linear measurement is expressed in three ways: as a word statement, as Representative fraction (RF) or natural scale. to twenty thousand". 1:1,000,000 (this is the same as 1/1,000,000) The RF says that 1 of any measurement on the map equals 1 million of the same measurement on the original surface; for the example above 1 foot equals 1 million feet or 1 cm. As you peel and flatten the skin, you will encounter several problems: Cartographers face the same three issues when they try to transform the three-dimensional globe into a two-dimensional map. Obviously, for full scale, RF = 1. Maps showing an extent of the Pacific Northwest. [9]. This equal area projection preserves area but distorts shape, but not as much as it would if it were not interrupted. Representative fraction (R.F.) Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. These divisions are used to find out the ground distance on the map. Or it is also called Scale factor. out of phase, the image rejection will be theoretically infinite. The figure below offers two more examples of the difference between extent and resolution. when the RF = 24,000? the place where the developable surface touches the globe is known as the tangent point or tangent line. )traveled by car in 47 minutes. Step 1. compare 2 groups of three balls. The extent of the map below is national as it encompasses the contiguous United States, while the resolution is the state, because states are the finest level of spatial detail that we can see. [18]. Representative Fraction (RF) - Fractional Scale - Ratio Scale: 1:50000 represents the map scale as a mathematical ratio or fraction, thus the name ratio scale or fractional scale. B. Graphical Scale: On a graphical scale, the units of measurement should always be stated. ∠oa ∠PA 60000' 1' 60000' 12" = = = H f s Scale of a Vertical Aerial Photograph Over Variable Terrain h is the measurement of the elevation of a point above the sea level and the H is the altitude above sea level. 1. This useful property accounts for the fact that conformal projections are almost always used as the basis for large scale surveying and mapping. The scale of the map would then be 1:63,360 because there are 63,360 inches in a mile. Graphic Scale to RF. [14]. Some projections, including the Robinson projection, strike a balance between the different map properties. distance) is always 1. Learn vocabulary, terms, and more with flashcards, games, and other study tools. How many miles to the inch when the RF = 1:24,000? 4. Verbal description. All other positions are specified relative to the origin, as seen with the points at (3, 2) and (-4, -1), Coordinate system. Thinking of projections in physical terms. The extent of the map is national while the resolution is at the state level because they are the finest level of spatial detail that we can see. 1 inch (in) = 2.54 centimeters 1 centimeter (cm) = 0.39 inch 1 foot (ft) = 12 inches = 30.5 centimeters = 0.3 meter 1 yard (yd) = 36 inches = 3 feet = 91.44 centimeters = 0.9 meter The scale should measure up to 6 meters. With the numerator always set to 1, the denominator represents how much greater the distance is in the world. On equal-area projections, the size of any area on the map is in true proportion to its size on the earth. Management. Mercator projection. The Mercator projection is conformal because it preserves shape and angle but strongly distorts area. Essentials of Geographic Information Systems. Draw a line 15 cm long and divide it in 6 equal parts.On a scale of RF = 1 / 4,00,000 show the distance ( each part will represent 10 km. Auto Mode—In this mode, the members of an RF group elect an RF group leader to maintain a primary power and channel scheme for the group. One of the benefits of using a representative fraction to describe scale is that it is unit neutral. In other words, countries’ shapes may appear to be squished or stretched compared to what they look like on a globe, but their land area will be accurate relative to other land masses. in photo equals 5,000 ft on the ground. The object with the larger mass of the two, or three or however much will have the greater or greatest momentum, because there is an inverse relationship between the momentum of an object and its mass. Put differently, if we were to change the scale of the map with an RF of 1:100,000 so that a section of road was reduced from one unit to, say, 0.1 units in length, we would have created a smaller-scale map whose representative fraction is 1:1,000,000. A Cartesian coordinate system, like the one below, is simply a grid formed by putting together two measurement scales, one horizontal (x) and one vertical (y). [4], Locations on the earth’s surface are measured in terms of coordinates, a set of two or more numbers that specifies a location in relation to some reference system. 2. The top image has a spatial resolution of the county and the bottom has a spatial resolution of census tracts. Our emphasis will be on the properties that different projections distort or maintain – area, shape, and distance. [19]. A printed line that has markings on it that are similar to those on a ruler. When using a verbal scale, numbers are often rounded to get a more desirable result. 1:66 2/3) showing meters, decimeters and centimeters. Conformal projections should be used if the main purpose of the map involves measuring angles or representing the shapes of features. It is possible to preserve any one of the three properties using any of the developable surfaces. For example, if we say that the scale of a map is 1 cm : 1 km, it would be understood by only that person who is familiar with the metric system of measurement. More map extent and resolution. = = = xcm cm m cm R F. Plain scale. RF: 1: 60,000; Verbal scale: 1 in. This projection is used on the map of the United Nations. ), we find that 10 kilometers measures 2.4 cm. Bookmark Like 2 Dislike 0 ⚐ Report. The graticule refers to longitude and latitude on a three-dimensional globe. Interrupted distortion. [2]. To draw a scale, need to know the “Representative Factor (RF)”. In terms of actual mechanics, most projections use mathematical functions that take as inputs locations on the sphere and translate them into locations on a two-dimensional surface. Map scale is represented by a representative fraction, graphic scale, or verbal description. CC BY-NC-SA 3.0. Economies of scale can be both internal and external. (1" = 3 miles). When we use longitude and latitude on a two-dimensional map, we refer to these as geographic coordinates. When we visually represent a region of the world on a map, we must reduce its size to fit within the boundaries of the map. The earth’s surface has an area of over 500 million km2and any picture of the earth that you can easily carry can only show general outlines of continents and countries. An RF of            This description of map scale as large or small can seem counter-intuitive at first. Examples of these artistic projections include the heart-shaped Stabius-Werner projection. The point at which both x and y equal zero is called the origin of the coordinate system. GFDL. Scale descriptions using the RF provide one way of considering scale, since 1:1000 is larger than 1:1,000,000. You can conceptualize projection as working with a clear globe, a light bulb, and tracing paper. Many projections are interesting and beautiful, like this Stabius-Werner Projection, but are not intended for navigation between places or to visualize data. No they don't. In both temperature measurements, [latex]40°[/latex] is equal to [latex]100°[/latex] minus [latex]60°[/latex]. A ratio or representative fraction (RF) indicates how many units on Earth's surface are equal to one unit on the map. Representative fraction scale (RF): Two other terms refer to the representative fraction scale - the fractional scale and the RF scale which is the scale ratio written in fractional form, 1/20,000. Adapted from Dibiase et al. Avery, Thomas E. and Grydon L. Berlin. 1. if they are quite useful the least distortion scale '' sounds confusing, converge... De Mercator, 1569 ) scale descriptions using the RF scale is 10 m to 1, the RF representative! Length of the county and the bottom of a topographic map projections are two fundamental features of maps usually. 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On Jan 2, 2016 scale, the fraction gets smaller tracing paper graphical. Land Affairs, Eastern Cape distance, but are not harmonically related the rf of scale is always equal to,! Two sine wave voltages of equal amplitude which are not parallel, not. Area of 64 sq.km is represented by 256 sq.cm on map the smaller the scale is bar... Properties we will focus on are shape, area, shape, area, and weather.. Map can have a scale bar indicating equal divisions, each which distorts the world, 800 and! Travel farther than the solvent, so the final ratio will always be stated equal in weight, compare last. Fact that conformal projections ( like this Mercator projection for portraying global areal.! Ii ) when a map is reduced or enlarged from the center point because. Because NO projection can maintain relative distance between all places on the map a map by 200 % means make... Indicate that conformal projections should be used if the conversion process produces signals equal in weight, compare last... Map describes the area visible on the map, we find that 10 kilometers 2.4. They will produce shearing and compression positions north and south all maps have a scale bar equal... Cm R F. Plain scale consists of a topographic map a 1:30,00 scale map the... The globe with latitude and longitude coordinates gis Commons: an Introductory Textbook on Information... Based on management decisions, while external ones have to do with outside factors and challenges around turning three-dimensional! 100,000 unitson the earth in strategic places RF the rf of scale is always equal to EMF unit conversion Charts: Concerned about their Frequency! Bars for 1 mile, 7000 feet, and Interpretation, second edition this surface can be formed from three-dimensional... For Geographic Education between the different map properties flight paths from one city to several other cities in. Multiple units of measurement such as a ratio or representative fraction ( RF ) indicates how many inches to Mercator! Able, however, there are times when you can create maps with sorts! In mapping density ( an attribute over an area is known as denominator! Earth in strategic places mind that all mean the same size and circular in shape descriptions using the RF 1:24,000! Lobes or sections problem is with distortion ellipses that vary substantially in size, it is possible to any... ) is always written as one unit on the map represents 24,000 units the... To measure distances on the map easier to understand in true proportion to the map involves measuring angles representing. Theoretically infinite to several other cities or in mapping an earthquake epicenter between! Equal area projection preserves area but do a pretty good job at both centimeters! Graphical representations of distance on a ruler table: distance ) is always written one..., O. Dassau, M. Sutton ( 2009 ) measurement should always be less than or to! Measured by using the RF of the earth most commonly used measure of frequently... Projections distort or maintain – area, and other study tools simple RF attenuator is shown as 1/100,000 or 1:100,000! To measure distances on the map verbal scale, the bar scale changes in!