what does 10 m s to the north describe
(b). Location, Distance, and Management on Maps
Location on Maps
Most maps allow united states to specify the location of points on the Earth's surface using a coordinate system. For a two-dimensional map, this coordinate arrangement tin use simple geometric relationships between the perpendicular axes on a grid system to ascertain spatial location. Figure 2b-1 illustrates how the location of a point tin can be defined on a coordinate system.
Figure 2b-i : A grid coordinate organisation defines the location of points from the distance traveled along 2 perpendicular axes from some stated origin. In the case higher up, the 2 axes are labeled X and Y. The origin is located in the lower left hand corner. Unit of measurement distance traveled along each axis from the origin is shown. In this coordinate system, the value associated with the X-axis is given first, following by the value assigned from the Y-axis. The location represented past the star has the coordinates 7 (X-axis), 4 (Y-axis).
Two types of coordinate systems are currently in general utilise in geography: the geographical coordinate arrangement and the rectangular (also called Cartesian) coordinate organisation.
Geographical Coordinate Organisation
The geographical coordinate system measures location from only two values, despite the fact that the locations are described for a 3-dimensional surface. The two values used to ascertain location are both measured relative to the polar centrality of the Earth. The two measures used in the geographic coordinate organisation are called latitude and longitude.
Figure 2b-2: Lines of latitude or parallels are fatigued parallel to the equator (shown in red ) as circles that span the Globe's surface. These parallels are measure in degrees (°). In that location are 90 angular degrees of latitude from the equator to each of the poles. The equator has an assigned value of 0°. Measurements of latitude are also defined as existence either north or south of equator to distinguish the hemisphere of their location. Lines of longitude or meridians are circular arcs that meet at the poles. There are 180° of longitude either side of a starting meridian which is known the Prime number Elevation. The Prime Elevation has a designated value of 0°. Measurements of longitude are also defined as being either west or e of the Prime Height.
Latitude measures the north-south position of locations on the World's surface relative to a point found at the center of the Earth (Figure 2b-ii). This primal signal is also located on the Earth'south rotational or polar axis. The equator is the starting point for the measurement of latitude. The equator has a value of nothing degrees. A line of latitude or parallel of 30° North has an angle that is 30° n of the aeroplane represented by the equator (Effigy 2b-3). The maximum value that latitude tin achieve is either ninety° North or S. These lines of breadth run parallel to the rotational axis of the Earth.
Longitude measures the w-due east position of locations on the Earth'due south surface relative to a circular arc called the Prime Meridian (Figure 2b-2). The position of the Prime Tiptop was determined by international understanding to be in-line with the location of the one-time astronomical observatory at Greenwich, England. Because the Earth'south circumference is similar to circle, it was decided to measure longitude in degrees. The number of degrees found in a circle is 360. The Prime Elevation has a value of zero degrees. A line of longitude or pinnacle of 45° West has an angle that is 45° due west of the aeroplane represented by the Prime number Meridian (Effigy 2b-3). The maximum value that a meridian of longitude tin can have is 180° which is the altitude halfway around a circle. This meridian is chosen the International Engagement Line. Designations of westward and east are used to distinguish where a location is plant relative to the Prime Peak. For example, all of the locations in North America take a longitude that is designated w.
Universal Transverse Mercator System (UTM)
Some other commonly used method to describe location on the Earth is the Universal Transverse Mercator (UTM) grid system. This rectangular coordinate organization is metric, incorporating the meter every bit its basic unit. UTM too uses the Transverse Mercator projection system to model the World's spherical surface onto a two-dimensional plane. The UTM system divides the earth's surface into 60 - half dozen degree longitude wide zones that run due north-due south (Effigy 2b-5). These zones start at the International Date Line and are successively numbered in an eastward direction (Effigy 2b-v). Each zone stretches from 84° North to 80° South (Effigy 2b-4). In the center of each of these zones is a central meridian. Location is measured in these zones from a false origin which is determined relative to the intersection of the equator and the central meridian for each zone. For locations in the Northern Hemisphere, the false origin is 500,000 meters west of the fundamental peak on the equator. Coordinate measurements of location in the Northern Hemisphere using the UTM system are made relative to this point in meters in eastings (longitudinal distance) and northings (latitudinal distance). The bespeak defined past the intersection of 50° N and nine° Westward would have a UTM coordinate of Zone 29, 500000 meters east (E), 5538630 meters north (N) (encounter Figures 2b-four and 2b-v). In the Southern Hemisphere, the origin is 10,000,000 meters south and 500,000 meters west of the equator and central meridian, respectively. The location found at 50° Due south and 9° Due west would accept a UTM coordinate of Zone 29, 500000 meters E, 4461369 meters N (recollect that northing in the Southern Hemisphere is measured from 10,000,000 meters south of the equator - see Figures 2b-4 and 2b-5).
Effigy 2b-4: The post-obit illustration describes the characteristics of the UTM zone "29" found between 12 to 6° Due west longitude. Note that the zone has been split into ii halves. The half on the left represents the area found in the Northern Hemisphere. The Southern Hemisphere is located on the right. The blue line represents the central acme for this zone. Locations measurements for this zone are calculated relative to a false origin. In the Northern Hemisphere, this origin is located 500,000 meters w of the equator. The Southern Hemisphere UTM measurements are determined relative to a origin located at 10,000,000 meters s and 500,000 meters due west of the equator and central meridian, respectively.
The UTM organisation has been modified to brand measurements less confusing. In this modification, the six caste wide zones are divided into smaller pieces or quadrilaterals that are eight degrees of breadth tall. Each of these rows is labeled, starting at 80° S, with the letters C to 10 consecutively with I and O being omitted (Effigy 2b-5). The last row X differs from the other rows and extends from 72 to 84° Northward breadth (twelve degrees alpine). Each of the quadrilaterals or grid zones are identified by their number/letter designation. In total, 1200 quadrilaterals are divers in the UTM organisation.
The quadrilateral system allows us to further ascertain location using the UTM system. For the location 50° N and 9° West, the UTM coordinate can now be expressed as Grid Zone 29U, 500000 meters E, 5538630 meters N.
Figure 2b-5: The UTM system also uses a grid system to break the Globe up into 1200 quadrilaterals. To proceed the illustration manageable, most of these zones have been excluded. Designation of each quadrilaterals is achieved with a number-letter system. Along the horizontal bottom, the vi degree longitude wide zones are numbered, starting at 180° Due west longitude, from 1 to 60. The twenty vertical rows are assigned letters C to Ten with I and O excluded. The letter of the alphabet, C, begins at 80° South latitude. Note that the rows are eight degrees of breadth broad, except for the last row 10 which is 12 degrees wide. Co-ordinate to the reference system, the bright green quadrilateral has the grid reference 29V (notation that in this system west-due east coordinate is given commencement, followed by the south-north coordinate). This filigree zone is constitute betwixt 56 and 64° North latitude and six and 12° West longitude.
Each UTM quadrilateral is further subdivided into a number of 100,000 by 100,000 meter zones. These subdivisions are coded past a system of letter combinations where the same two-letter combination is not repeated inside xviii degrees of latitude and longitude. Within each of the 100,000 meter squares one tin specify location to one-meter accurateness using a 5 digit eastings and northings reference arrangement.
The UTM grid system is displayed on all United States Geological Survey (USGS) and National Topographic Series (NTS) of Canada maps. On USGS 7.5-minute quadrangle maps (1:24,000 calibration), fifteen-minute quadrangle maps (1:fifty,000, 1:62,500, and standard-edition ane:63,360 scales), and Canadian 1:50,000 maps the UTM grid lines are fatigued at intervals of 1,000 meters, and are shown either with blueish ticks at the edge of the map or by full blue grid lines. On USGS maps at 1:100,000 and 1:250,000 scale and Canadian ane:250,000 scale maps a full UTM grid is shown at intervals of 10,000 meters. Figure 2b-6 describes how the UTM filigree organization can exist used to decide location on a 1:50,000 National Topographic Series of Canada map.
Figure 2b-half dozen: The top left manus corner the "Tofino" 1:50,000 National Topographic Series of Canada map is shown above. The blue lines and associated numbers on the map margin are used to determine location by way of the UTM grid system. Abbreviated UTM 1,000-meter values or principle digits are shown by numbers on the map margin that vary from 0 to 100 (100 is actually given the value 00). In each of the corners of the map, two of the principle digits are expressed in their full UTM coordinate form. On the image we can come across 283000 chiliad E. and 5458000 m N. The red dot is plant in the centre of the grid defined past principle numbers 85 to 86 easting and 57 to 58 northing. A more complete UTM filigree reference for this location would be 285500 grand E. and 5457500 thousand Northward. Information found on the map margin besides tells u.s. (not shown) that the area displayed is in Grid Zone 10U and the 100,000 m squares BK and CK are located on this map.
Distance on Maps
In section 2a, w e have learned that depicting the Globe'southward three-dimensional surface on a ii-dimensional map creates a number of distortions that involve distance, area, and management. It is possible to create maps that are somewhat equidistance. Still, even these types of maps accept some form of distance distortion. Equidistance maps tin only control distortion along either lines of latitude or lines of longitude. Distance is often correct on equidistance maps only in the direction of latitude.
On a map that has a large scale, 1:125,000 or larger, distance distortion is usually insignificant. An example of a big-scale map is a standard topographic map. On these maps measuring straight line distance is simple. Distance is first measured on the map using a ruler. This measurement is so converted into a real globe altitude using the map'southward calibration. For example, if we measured a distance of 10 centimeters on a map that had a scale of 1:10,000, we would multiply 10 (distance) by 10,000 (scale). Thus, the actual distance in the real world would be 100,000 centimeters.
Measuring distance along map features that are not straight is a little more difficult. One technique that can be employed for this chore is to use a number of straight-line segments. The accuracy of this method is dependent on the number of straight-line segments used (Figure 2b-seven). Some other method for measuring curvilinear map distances is to apply a mechanical device called an opisometer. This device uses a small rotating wheel that records the distance traveled. The recorded distance is measured by this device either in centimeters or inches.
Figure 2b-vii : Measurement of distance on a map feature using straight-line segments.
Management on Maps
Like distance, management is hard to mensurate on maps because of the baloney produced by project systems. Nonetheless, this distortion is quite modest on maps with scales larger than 1:125,000. Direction is usually measured relative to the location of North or Southward Pole. Directions adamant from these locations are said to exist relative to True Northward or True S. The magnetic poles can also exist used to measure direction. However, these points on the Earth are located in spatially different spots from the geographic Due north and South Pole. The North Magnetic Pole is located at 78.3° North, 104.0° Due west near Ellef Ringnes Island, Canada. In the Southern Hemisphere, the S Magnetic Pole is located in Commonwealth Day, Antarctica and has a geographical location of 65° S, 139° East. The magnetic poles are also not fixed overtime and shift their spatial position overtime.
Topographic maps normally have a declination diagram drawn on them (Figure 2b-8). On Northern Hemisphere maps, declination diagrams draw the athwart divergence betwixt Magnetic North and True North. On the map, the bending of True North is parallel to the depicted lines of longitude. Declination diagrams also show the management of Grid Northward. Grid North is an angle that is parallel to the easting lines found on the Universal Transverse Mercator (UTM) filigree organization (Figure 2b-eight).
Figure 2b-8: This declination diagram describes the athwart departure between Grid, True, and Magnetic North. This analogy as well shows how angles are measured relative filigree, true, and magnetic azimuth.
In the field, the management of features is often determined by a magnetic compass which measures angles relative to Magnetic North. Using the declination diagram found on a map, individuals tin can convert their field measures of magnetic direction into directions that are relative to either Grid or True North. Compass directions can be described past using either the azimuth system or the bearing organization. The azimuth system calculates direction in degrees of a full circumvolve. A full circle has 360 degrees (Figure 2b-nine). In the azimuth system, n has a management of either the 0 or 360°. E and west have an azimuth of 90° and 270°, respectively. Due south has an azimuth of 180°.
Figure 2b-nine: Azimuth system for measuring direction is based on the 360 degrees found in a full circumvolve. The illustration shows the angles associated with the major central points of the compass. Note that angles are determined clockwise from n.
The bearing organization divides direction into four quadrants of ninety degrees. In this organisation, north and south are the dominant directions. Measurements are adamant in degrees from one of these directions. The measurement of two angles based on this organisation are described in Effigy 2b-10.
Figure 2b-x: The bearing arrangement uses four quadrants of ninety degrees to measure direction. The analogy shows two direction measurements. These measurements are fabricated relative to either north or south. North and south are given the measurement 0 degrees. Eastward and west have a value of 90 degrees. The first measurement (greenish) is institute in the north - e quadrant. As a result, its measurement is n 75 degrees to the east or N75°E. The first measurement (orange) is found in the due south - west quadrant. Its measurement is south 15 degrees to the west or S15°W.
Global Positioning Systems
Decision of location in field conditions was once a difficult task. In most cases, it required the utilize of a topographic map and mural features to judge location. Notwithstanding, technology has now made this job very unproblematic. Global Positioning Systems (GPS) can calculate one'south location to an accuracy of about 30-meters (Figure 2b-11). These systems consist of two parts: a GPS receiver and a network of many satellites. Radio transmissions from the satellites are broadcasted continually. The GPS receiver picks upwardly these broadcasts and through triangulation calculates the altitude and spatial position of the receiving unit. A minimum of iii satellite is required for triangulation.
Effigy 2b-eleven: Handheld Global Positioning Systems (GPS). GPS receivers tin can make up one's mind latitude, longitude, and height anywhere on or to a higher place the Earth'due south surface from signals transmitted past a number of satellites. These units can also be used to decide direction, altitude traveled, and decide routes of travel in field situations.
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