just answer questions and do exercises
The “Geography I ES 1101 Lab 1: Topographic Map Reading This lab exercise is designed to familiarize you with many of the fundamental concepts associated with spatial investigation of the earth system. In the first part of the exercise you will be introduced to the various types of maps. In the second part of the exercise you will explore one particular type of map, the topographic map, in more depth. PART ONE: Maps are among the most important of the visual and conceptual tools Earth scientists use to study the physical surface of the Earth. Maps can show the location and distribution of almost anything, but Earth Scientists use certain kind of maps frequently: Planimetric maps are the simplest type of map. They depict the location of major cultural and geographic features such as towns, rivers, roads, and railroads. Most people are familiar with this kind of map. Highway maps, city plans, maps located using an Internet search engine (i.e. Google Maps), and the campus map in your college handbook are examples. Topographic maps are more complicated and contain elevation information in addition to the features that planimetric maps show. Features such as valleys, steep slopes, and mountain peaks—which may only be sketchily indicated on a planimetric map—are clearly represented in shape and form on a topographic map using various types of colors or symbols. Figure 1. Topographic mapping and contour lines Figure 1. Figure 2. Topographic map example on the iPhone app “AllTrails” Figure 3. Components of a topographic map Bathymetric maps do for the ocean floor or a lake bottom what topographic maps do for the land. In coastal areas, bathymetric maps are particularly useful for marine navigation because they show possible submerged nautical hazards. They also show the submarine canyons, trenches, ridges, and plains that make up the ocean floor. (Figure 4) Geologic maps show the distribution of rock masses in patterns or colors or both. Geologic maps may be lithologic as in Figure 5 (top) showing the rock types, or chronologic showing the age of the rocks in Figure 4 (bottom), or both. Weather maps show the distribution of aspects of the weather, such as storm systems, precipitation, and temperature, including warm and cold fronts (Figure 6). Figure 4 Topographic and bathymetric map of Crater Lake, Oregon Figure 5. Geologic maps Figure 6. A weather map Other maps: Many more types of maps exist than we can discuss here. Some examples include maps of ocean currents, maps showing climate zones, vegetation maps, land use maps, and maps showing the plate boundaries of the Earth’s lithosphere, and so on. We will see more in the semester. Virtual earth represents the world not in a 2D flat way but with a 3D globe. Modern information technology has allowed the representation of large amount of information and fast online virtual earth explorations. Examples include Google Earth, Microsoft’s virtual globe, and NASA World Wind. PART TWO: - 2 - 5 Note: Please type your answers in the spaces provided following each question at the end of this document and submit your completed document on Blackboard. Topographic maps in detail: Topographic maps reveal aspects of earth's surface, its hills and valleys, lakes and streams, towns and roads. The most common way of representing three-dimensional topography on a two-dimensional map is through the use of contour lines. A contour line is a continuous line of the same elevation. Learning how to read topographic maps is an exercise in learning how to read contour lines. With practice, you can look at a topographic map and, through its contour lines, visualize the landscape. Try this: Focus on Figure 7a, below. Figure 7a Figure 7a is a sample topographic map; as such, you are looking down on the map as if you were way above, perhaps in an airplane at 15,000-20,000 ft. in altitude. You can only “see” two dimensions, unless you are practiced at reading contour lines. Once you become familiar with how contour lines work you will be able to “see”—or, visualize—the actual ups and downs in the landscape; you can visualize the topography, shown clearly in the oblique view (Figure 7b) of the same area pictured in Figure 1a, above. Figure 7b Preparation 1. Before beginning this exercise, you are suggested to watch this introductory video on how to read a topographic map (feel free to check out the related videos, too): https://www.youtube.com/watch?v=CoVcRxza8nI&t=14s 2. USGS 7.5 minute topographic maps All topographic maps produced by the U.S. Geological Survey (USGS) are oriented with north at the top of the map. Therefore, if you locate a position on the map, and move towards the top of the map, you are moving in a northerly direction, and if you are moving to the bottom of the map, you are moving towards the south. Any movement to the right will be towards the east, and a movement towards the left will be towards the west. Figure Latitude and Longitude grid system of the Earth Author: Karen Tefend Source: Original Work License: CC BY-SA 3.0 These maps are oriented with their sides parallel to lines of longitude (meridians) and the top and bottom edges parallel to lines of latitude. The latitude and longitude coordinates of each topographic map are found at the corners of the map. Often these maps represent an area of the Earth that is smaller than one degree of distance. For example, a common topographic map will show only 7.5 minutes of distance (7’ 30”) for both latitude and longitude; in this case, the top and bottom edges of a map will represent a distance of 7.5 minutes of latitude, and the left and right edges of the map will represent a distance of 7.5 minutes of longitude. The USGS archives the entire country’s topographic maps in terms of such 7.5 minute quadrangles. An illustration of NJ’s 7.5 minute quadrangle layouts can be found here: https://www.state.nj.us/dep/njgs/pricelst/quadindex.htm Because the degree is unchanging on the map, a shorthand notation of just the change in minutes and seconds is labelled at certain positions on the map’s edge. Only at the corners of the map will the degrees be included for the latitude and longitude coordinates. See the example below, which shows on the top right corner of a 7.5-minute map or 7.5 minute quadrangle (the dimension of most topographic maps). Additional numbers other than latitude and longitude are also shown on the edges of the map; these are a different grid system and will not be explained here. Map scales are provided on topographic maps so that a map reader can measure the distance between two points on a map, or even to calculate the gradient of a hill or river. The two commonly used map scales on a topographic map are the bar scale (or graphical scale) and the fractional scale (also known as a ratio scale). The figure below shows three bar scales; each bar is a graphical representation of distance on the map, and it is up to the map reader to decide if they want to measure distances in kilometers, meters, miles, or feet. To find the distance between any two points on a map, a person could use a piece of paper to transfer the two points down to the bar scale and read the distance directly from the bar scale. Notice that each bar scale has the starting point (zero) within the interior of the scale, and not on the end of each scale. The other type of map scale is the fractional scale; in the Figure the fractional scale is 1:24,000. No units are reported as this ratio of 1 to 24,000 is valid for any unit of measure, provided that it is the same unit. For example, if using inches, then this map scale indicates that 1 inch on the map is actually covering 24,000 inches of ground (the distance between two locations in the real world). Or if using centimeters, then 1 centimeter on the map is actually covering 24,000 centimeters of ground. One way to describe map scale is to talk about 'large scale' or 'small scale' maps. This terminology can be very confusing, because it is the opposite of what our intuition says it should be. When geographers talk about a 'large scale map' they are speaking about a map of a small area, like the college campus or a small city (1:24,000 to 1:100,000). When geographers talk about a 'small scale map' they are speaking about maps of large areas such as all of the US, Europe or the world (1:250,000 and up). The table below is a quick reference guide to help you become familiar with geographer-speak. Large Scale vs. Small Scale Maps "Large Scale" "Small Scale" Small features are large Large features are small, or don't exist A map of this room A map of this state A map of this campus A map of this country A map of this city A map of this world Now, let’s read an actual topographic map to further learn how to use it. Your Exercise In this part you will read a topographic map of your area. Use the map provided in class to answer the following questions: 1. Locate the map’s scale and identify a few of the natural and cultural features depicted on the map. 2. Orient yourself by locating Watchung Mountains, Passaic River, and Plainfield. Recall that the contour lines on the map are used to represent equal values of elevation. All points along a particular contour line, for example, are located at the same elevation above sea level. The distance between these lines denotes a specified change in elevation, and is referred to as a contour interval. All maps assign a fixed contour interval. 3. What is the contour interval assigned to the map of Chatham? 4. Find the elevations at the highest point of First Watchung Mountain, Second Watchung Mountain, Long Hill, and the bottom of Watchung Mountain (defined by Highway 22). Do we know the precise elevation at the top of Watchung and Long Hill? Why or why not? The aspect of a slope is defined as the compass direction in which a slope faces as it descends in elevation. This can be tricky: any hill can have a number of different sides, and hence any hill can have a number of different aspects. It all depends on which direction you are facing downhill. If it helps, think about aspect as the direction that water would travel most quickly down a given slope. N B A D C 100 ft. 80 ft. Aspect of Slope AB = Southwest Aspect of Slope CD = South 5. Define the aspects of points A through F on the map of Chatham