What Are Contour Lines And Topographic Maps
Ever noticed those squiggly lines all over your hiking map? Other than the obvious trails and rivers, these squiggly lines are contour lines.
Put simply, contour lines mark points of equal elevation on a map. If you trace the length of a line with your finger, each point you touch is the same height above sea level. If you were to walk the path of a contour line in real life, you would remain at the same elevation the whole hike, never traveling up or down.
Contour lines are critical to understanding the elevation profile of your terrain or a particular land formation. This information can be helpful when selecting a hiking route… or lifesaving in a desperate survival situation. Beyond backpacking and hiking, countless other professions use them – land surveyors, foresters, engineers, miners, geologists, hunters, to name a few.
Topography is the study of geographical features on a landscape. A map with contour lines on it is called a topographic map. Topographic maps use a combination of colors, shading and contour lines to represent changes in elevation and terrain shape. Essentially, topographic maps represent the three-dimensional landscape of Earth within the two-dimensional space of a map.
What Is A Grid For 5th Class
A man made system used to accurately measure the position of any place on surface of earth the grid marks the location of place by use of latitude and longitude. A grid system in graphic design uses a two-dimensional framework. Earth has a geographical grid. This grid is found on the globes and on flat maps.
Custom Overlay Reference Grids
You can create custom overlay reference gridsthat use the geometry of a line or polygon data source to definethe grid lines and an attribute column in this same feature classto specify the labels. A custom overlay grid allows you to superimpose anirregular or specialized reference system.
You might use custom overlay grids if you want to create grids for the following:
- Boundaries of a U.S. state plane coordinate system zone
- Boundaries of a world geographic reference system
- Boundaries of the extents of OperationalNavigation Chart or Joint Operations Graphic maps
- Boundaries of the U.S. Geological Survey quad sheets at the various scales at which they are produced
- Boundaries of the extents of International Map ofthe World map sheets
- Boundaries of world time zones and UTMzones
- When using the Military Grid Reference System, which includesthe grid zones and 100,000-meter boundaries necessary to refer to alocation using MGRS coordinates
Custom overlay grids do not handle cases where the map crosses UTM zones. If your map crosses a UTM zone, you should consider using a Grid and Graticule layer.
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Important Meridians On The Geographic Grid
The Prime Meridian and the International Date Line are important meridians and points of reference. The Prime Meridian which runs through Greenwich, England and is sometimes known as the Greenwich Meridian is the origin point of all other measurements and has a longitudinal designation of zero degrees. We measure other longitudes by the degrees of distance away from the Prime Meridian.
On the opposite side of the globe is the International Date Line, which sits along the 180 degree measurement. The International Date Line is the line of demarcation between calendar days crossing that line puts you in a different day. Those moving from west to east across the line move forward one day and those moving from east to west move backward one day.
Meridians: Lines Of Longitude
Lines of longitude, also known as meridians, are imaginary lines that run vertically in a north-south direction from the poles. The meridians come together and meet at the poles, and have their widest separation at the Equator. Most maps show measurements of these lines in increments of 30 degrees. Lines of longitude indicate how far east or west you are of the Prime Meridian.
Drawing The Earth Grid
To draw the lines of the grid system on a globe or map, it is necessary to have starting points, or points of reference. There are two such points of reference on the Earth. These are the North Pole and the South Pole. The poles are the points at which the Earths axis meets the Earths surface. Halfway between the poles is an east-west line called the equator. It encircles the Earth and divides it into two equal parts, or hemispheres. The North Pole is in the hemisphere north of the equatorthe Northern Hemisphere. The South Pole is in the hemisphere south of the equatorthe Southern Hemisphere.
One set of lines in the Earths grid system is drawn around the globe parallel to the equator. These are east-west lines, or lines of latitude. In the basic grid there are 89 such equally spaced lines to the north of the equator, 89 to the south. Where the 90th east-west lines would be are two pointsthe North and South poles. Each east-west line is a circle. The farther it is from the equator the shorter its length. The 60th east-west line, for example, is only half as long as the equator.
North-south lines are numbered from 0 at the north-south base line both east and west to the 180th north-south line. The zero line and the 180th line together form a complete circle that, like the equator, cuts the Earth into two hemispheres. The half west of the zero line can be called the Western Hemisphere the half east of the zero line, the Eastern Hemisphere.
What Is Grid In Geography For Kids
A system of lines is used to find the location of any place on the surface of the Earth. Commonly called a grid system, it is made up of two sets of lines that cross each other. One setlines of latituderuns in an east-west direction. The other setlines of longituderuns in a north-south direction.
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How Does The Grid Help Us In Locating A Place On The Globe
The grid helps people locate places on the map. On small-scale maps, the grid is often made up of latitude and longitude lines. The intersection of latitude and longitude lines, called coordinates, identify the exact location of a place. On maps showing greater detail, the grid is often given numbers and letters.
Additional Resources For Latitude And Longitude
YouTube Break: The Clock That Changed the World
An explanation of using time for navigation and satellite navigation .
Run Time: 29 minutes, but really well done and quite interesting. Highly recommended to better understand the geographic grid that is longitude and latitude.
- Note: SatNav = GPS Receiver
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How Is Grid Useful
Grids are helpful in pin-pointing the exact location on Earth. The geographical coordinates usually refers to longitudes and latitudes, as they provide systematic network of lines upon which the position of various surface features of the earth, can be represented. Each minute is divided into 60 seconds .
What Is A Geographic Grid
The geographic grid is a system designed to pinpoint any location on Earth by laying a vertical and horizontal grid over the Earths layout. The vertical lines are called the longitude and the horizontal lines are the latitude. The intersection of these two points determines any exact location.
The geographic grid is fundamental to the study of geography because its medium of communication relies so heavily on the use of maps. The lines are a man-made invention based off the location of the north and south poles.
Latitudinal lines measure degrees north to south, with 0 degrees being the exact halfway point between the north and south poles. Longitudinal lines measure degrees east to west, running vertically between the north and south poles.
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What Is Grid Wikipedia
Meaning an array of squares or rectangles: Grid plan, a city plan in which streets run at right angles to form a grid. Grid reference, a standard method for the location of a point on a map. Grid in typography and page layout: planning a page using a grid of different-sized and -shaped rectangles on computer software.
How Does Grid Help To Locate A Place
The grid helps people locate places on the map. On small-scale maps, the grid is often made up of latitude and longitude lines. Latitude lines run east-west around the globe, parallel to the Equator, an imaginary line that circles the middle of the Earth. Longitude lines run north-south, from pole to pole.
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Finding Latitude And Longitude
The navigator of a ship or an airplane can determine latitude by using an instrument called a sextant. With it the navigator measures the altitude of the Sun as the Sun transits, or crosses, the meridian .
The navigator then calculates the latitude by combining the observed altitude with information from an almanaca book of data about the movement of the Sun and stars. In the evening, latitude may similarly be found by observing stars .
Longitude is more difficult to determine than latitude because the sextant and the almanac together do not yield enough information. To calculate longitude, a navigator must also know the exact time at which the observations are made. The time is needed because the Sun and stars, as they appear to move across the sky, look the same at all places in a given latitude at some time during each day.
Shipboard chronometers are set to show GMT. Because of the speed and direction of the Earths rotation, local time at a given place will be one hour behind GMT for every 15 degrees west of the prime meridian and one hour ahead of GMT for every 15 degrees east of the prime meridian. For example, if a ships chronometer reads 0300 and the ships local time is 0800 , the ship is 75 degrees east of Greenwich, or at 75° E. Special radio time signals allow navigators to check the accuracy of their chronometers.
What Are Grid Lines
Gridlines in Excel are the horizontal and vertical gray lines that differentiate between cells in a worksheet. The gridlines guide users to differentiate between the specific cells and read the data in an organized manner. They also help users navigate through the worksheet columns and rows with ease.
What Do You Need To Locate A Place On The Globe
Any point on earth can be located by specifying its latitude and longitude, including Washington, DC, which is pictured here. Lines of latitude and longitude form an imaginary global grid system, shown in Fig. 1.17. Any point on the globe can be located exactly by specifying its latitude and longitude.
Grid In Geography Topic
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Presentation On Theme: Define Grid Reference Explain Why Grids Are Important Use A Grid System To Locate Places On A Map Presentation Transcript:
2 Define grid reference Explain why grids are important Use a grid system to locate places on a map
3 What is a grid reference A grid reference is a standard method for the location of a point on a map. The grid itself is a coordinate system imposed on a map.
4 What is a Grid System 1. Map grids are drawn on maps to help mapmakers find the exact location of a place. 2. A grid is a system of horizontal and vertical lines that cross each other to form squares.
5 What a grid system looks like
6 How is a grid system used http://olc.spsd.sk.ca/DE/k9mod/Mapskill/grid1.swf Remember the Location of something on a grid is given as Letter then Number for example A6 or the park is in A6
7 The Latitude & Longitude grid system When latitude and longitude are combined on a map or globe they form a grid system. What does it look like when latitude and longitude form a grid system.
8 Latitude and Longitude Grid System
9 Lets apply our knowledge Turn to the map of The Bahamas in the back of our classroom 1A.Where is the national fish of The Bahamas located? 1b. 2a. Where is the national flower of The Bahamas located? 2b. 3a. Where is the national bird of The Bahamas located? 3b. Next slide for conclusion
10 Conclusion Turn to page 52 in your atlas for quick practice 1.What island and continent is located at H3? 2.What countries are located at C4? 3.What is the location of The Bahamas?
How To Read Contour Lines
A quick glance at a topographic map will give you a general idea of the landscape. Is it flat or mountainous?
If each line represents an equal point of elevation, then any change in elevation would lead to inconsistent line spacing, right? For example, several contour lines spaced close together would indicate steep terrain, while lines spaced far apart would indicate a gentler slope.
Let’s dig deeper. There are 3 kinds of contour lines youll see on a map: intermediate, index, and supplementary.
1. Index lines are the thickest contour lines and are usually labeled with a number at one point along the line. This tells you the elevation above sea level.
2. Intermediate lines are the thinner, more common, lines between the index lines. They usually don’t have a number label. Typically one index line occurs for every five intermediate lines.
3. Supplementary lines appear as dotted lines, indicating flatter terrain.
If youre looking at an index line, it’s easy to read the elevation because it is clearly labeled. However, interval lines are somewhat trickier. To determine their elevation, youll need to know the contour intervals. Contour intervals tell you the change in elevation between any two contour lines. You can find the contour interval in the map key, usually located underneath the scale of the map at the bottom center. To understand all map symbols, see the US Gov document.
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Mgrs And Us National Grid
The Military Grid Reference System is a grid-based system used to represent locations on the universal transverse Mercator and universal polar stereographic coordinate systems, expressed as an alphanumeric string. An MGRS coordinate defines an area on the Earth’s surface as opposed to a specific point. A fully qualified MGRS string is 15 characters long and consists of the following three components: grid zone designation, 100,000-meter square identifier, and easting/northing.
There are two methods for adding an MGRS or U.S. National Grid overlay to your map. If you need a dynamic grid that updates automatically as you pan and zoom, you can use the data frame grid properties with an MGRS or U.S. National Grid overlay grid. However, if you need to do one of the following, you will need to utilize a Grid and Graticule layer:
- Display the MGRS or U.S. National Grid in a coordinate system other than UTM
- Display UTM labels when your area of interest crosses UTM zones
- Display multiple MGRS or U.S. National Grid overlays within a single layout
- Display the MGRS or U.S. National Grid for rotated and nonrectangular areas of interest
- Change the MGRS or U.S. National Grid interval
- Place interior ladder labels for alternate intervals
Grid and Graticule layers support these complex grid and graticule scenarios. However, they are not dynamic and will not update as you pan and zoom.
Getting To Know Map Symbols
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Section Four: Latitude And Longitude
For as long as humans have had the goal to explore our planet, they have also had the need to devise a navigation method to make this process easier, and more importantly, a method which was reliable and repeatable. As these exploration and discovery missions took explorers over longer distances and away from land, which is super handy for sighting back to and knowing where you are, a world-wide system that could be used day or night was needed. With a rather long history of discovery, trail, and error, latitude and longitude became a world-wide grid system, giving an explorer the ability to know where they were at all times, with a general error of about 10 feet. Not too bad without a GPS receiver!
Latitude and longitude is an and is just one example of a geographic grid, utilizing a specific principle meridian, the Prime Median, and degrees as the angular unit of measure to label and later be able to navigate to locations on the Earths surface.
Geographic grids, it should be noted, are not a complete geographic coordinate system nor are they a datum. Latitude and longitude, albeit the most common – is not the only geographic grid out there. All of this reading is working towards the established goal of creating a tied down, worldwide “address system” we call a geographic coordinate system. The GCS is made up of two parts, one of which is a datum and the other of which is geographic grid .