Surveying Equipment

Several types of surveying equipments are available in the market today. Surveying equipments help in measuring various parameters of a land area. Each of these parameters is measured by a specific type of measuring equipment. In this article we will learn about the importance of the main types of surveying equipments, both old and new.

Surveying Equipments - Old

In ancient times surveying equipments such as chains, compass, solar compass, transit, theodolite etc, were used by the surveyors. Chains with equal sizes of links were used to measure distance between the two required points. A compass was used to measure the direction of a line that was being surveyed. A solar compass was used for measuring both the direction and latitude of a particular point with the help of sun and stars. Solar Compass could also measure horizontal angles and the ?true north? of a particular place. A metallic measuring tape was used to measure shorter distances.

As the technology gradually advanced with time, the instruments used for surveying also improved. The horizontal and vertical angles were measured using a simple theodolite whereas difference in heights was measured by a basic level. Measuring wheels were also initially used by surveyors to measure long distances in short duration of time. Measuring wheels were of two types ? mechanical and electrical, and both worked on the same principle of rolling the wheel from the start to the end point.

In the early 1900s, surveyors started to use surveying equipments such as planimeters, theodolites, automatic levels, measuring wheels etc. Planimeter is the best known tool for measuring asymmetrical land areas as they eliminate the need for charts or manual calculations; whereas a theodolite allows measuring of horizontal and vertical angles. Theodolite consists of a movable telescope attached over perpendicular axis. It provides precise measurement of angles and is an integral part of every surveying tool kit. Transit is a type of theodolite but has less precision.

Auto level or dumpy level is also a type of surveying equipment used for measuring horizontal levels. It consists of a telescope like device fitted on a tripod stand. Auto level, tilting level, and self-leveling level are all types of leveling instruments, each providing different rotating capabilities.

Maximum of the surveying instruments are fixed on a Tripod, which acts like a support to all these instruments. As the name suggests, tripods have three legs with length varying capability. Many of these equipments are still used by surveyors around the world.

Surveying Equipments - New

The development in technology has provided some of the finest surveying equipments present today. GPS has not only made surveying faster but has increased the accuracy to amazing heights. GPS works with the help of satellite systems which provide accurate data directly on the computer screen. GPS equipments are available of various types, from basic to highly advanced. Some of the GPS equipments even have night visions which facilitate surveying during the night time. However, it is said that though GPS helps in acquiring the exact position of the land; it does not provide good results in dense forest areas or concrete constructions. For this reason, an instrument known as total station is used along with the GPS.

Total station is a theodolite with an Electronic Distance Measurement Device. EDMD shifted the surveying technology from optical mechanical devices to digital electronic devices. In spite of just being distance measuring equipment, total station can also be used for leveling when adjusted in a horizontal plane. Most of the ultra-modern surveying devices are a combination of one or more of these devices.

Thus, there is a long list of surveying equipments available in the market today. The selection of particular equipment depends on the type of application and accuracy required. Though all these equipments provide a wide range of options to surveyors, it is advisable to have a thorough knowledge of both, the equipment and the desired survey. This would not only help in bringing accuracy to the work but would also save considerable time and money.

Map

Maps are the focal point for understanding geography. There are many ways to teach map reading. Learning how to find north, read a legend, distances and location are standard skills that are taught in geography. However, you can teach map reading skills and science at the same time. Maps become exciting when you use them to make understanding science easy.

A map is a picture or representation of the Earth's surface, showing how things are related to each other by distance, direction, and size. Maps are a way of showing many things about a portion of the earth's surface on a flat piece of paper that can be carried and transported easily. A map is not a photograph of the Earth's surface. It can show many things that a picture cannot show, and as a result, a map looks different in many ways from a photograph of the Earth's surface. Maps have been used for centuries. A person who creates map as a profession is called a cartographer.

Maps can be used in evaluating natural resources; in analyzing and forecasting weather conditions; in agriculture, fisheries, and general commerce; and in regional planning. Maps help in navigation and locating places by sea, air, and land. Maps are important to scientists concerned with the causes and effects of the distributions of phenomena, in such disciplines as geology, oceanography, meteorology, climatology, animal and plant ecology, agronomy, economics and the social sciences, as well as geography itself. Today maps are used by people to find places they have not seen. Let?s say you are asked to find the nearest high school from your house. You could walk aimlessly from your house and hope you find a school. However, if you were thinking, you would use a local map to help locate the nearest high school. The scale on the map can help you determine the distance and the legend reveals what map symbol is a high school. The direction in which you should walk can also be determined. However, you may need a compass to walk in the direction. Let?s learn about other types of maps and their uses.

According to the U.S. Geological Survey: "A topographical map is a line and symbol representation of naturaland selected man-made features of a part of the Earth's surface plotted to a definite scale. A distinguishing characteristic of a topographic map is the portrayal of the shape and elevation of the terrain by contour lines. Topographic maps show the location and shape of mountains, valleys, and plains; the networks of streams and rivers; and the principal works of man."

TOPOGRAPHIC MAPS

Topographic maps show a 3 dimensional world in 2 dimensions by using contour lines. Many people have trouble reading these maps, because they have mountains and valleys are represented with concentric circles and lines.

Many hikers use topographic maps, especially in areas where there are no roads with signs. Geologists depend on topographic maps to record the types of rocks. Engineers use topographic maps when they are planning roads, buildings, or other human?made structures. Imagine designing a city without considering where hills and valleys are located!

Geologic maps are difficult for students to understand because it shows the rocks that are on the surface of the Earth. However, a geologic map also provides ways in which you can tell how the rocks go into the Earth.

A geologic map is a map of the different types of rocks that are on the surface of the Earth. By mapping different rock types, geologists can determine the relationships between different rock formations which can then be used to find mineral resources, oil, and gravel deposits. Also, you want to know what type of rock you are building on or else you might have a Leaning Tower of Pisa or a pile of rubble after a strong earthquake.

BIOGEOGRAPHIC MAPS

Scientists involved in the study of animals, plants, and other living organisms use maps to illustrate where these groups live or migrate. It is important to many zoologists to know where the organisms that they study live and where they move to. People who monitor endangered species need to know if the ranges of migration have become larger or smaller through time.

ENVIRONMENTAL MAPS

These types of maps include maps that look at human's activity in urban and metropolitan areas and the environment in which we all live. Maps that illustrate physiographic features such as forests, grassland, woodland, tundra, grazing land, ocean floors, and ocean sediments could be included in this large grouping.

Meteorological maps that show climate, weather and wind are types of environmental maps.

Meteorologists, oceanographers, geographers, city planners, and many other professionals depend greatly on these maps to record and forecast their specific field.

Latitude identifies locations or distances in degrees north or south of the equator. Also note that each of these lines is numbered in degrees. The equator is numbered 0⁰ latitude. In the northern half of the globe or map, latitude is measured from 0⁰ at the equator to 90⁰ at the North Pole. The same is true for the southern half of the globe. Locations north of the equator are referred to by degrees north latitude.

Other lines on the globe or map pass through the poles. These lines are called meridians or lines of longitude. Longitude identifies locations or distances east or west of the prime meridian. They divide the Earth into 360⁰ similar to a sphere. Unlike lines of latitude, meridians are not parallel. They are farthest apart at the equator. They get closer together as they reach the poles, where the meridians meet. The starting point of longitude is called the prime meridian, which represents 0⁰ longitude. The east and west longitude lines meet at the 180⁰ meridian. This line is called the International Date Line.

Geographic Information Systems (GIS) combines layers of information to fully understand an area.

On a rainy weekend during the school year, you decide to visit the science museum that has just opened near your home. When you arrive, you discover that it is huge. There are more interesting things to see than you can possibly examine in an afternoon. How do you decide what to see? How do you find out where to go?

Luckily, inside the entrance of the museum, you see a row of computer stations. At each station, a screen displays a map of the museum. As you move the computer?s mouse over the map, a window appears telling you what is displayed in each area. You want to see the museum? s exhibit on gemstones. You notice that the computer screen has a search command. You enter the word ?gemstones?. The screen responds by highlighting the room on the map where gemstones are displayed. It also tells you how to get there from the museum entrance, as well as what gemstones are currently on display.

What is a Geographic Information System?

The program you used at the museum is an example of a geographic information system, or GIS. A GIS is a type of computer software. The basis for this software is a computerized map. Like a regular paper map, a GIS map shows where things are located. A GIS, however, is much more than a map. It also contains a database of information about the things on the map, such as what was displayed in each room of the museum. In addition, the GIS contains software that analyzes the database and map information to find connections between them. Searching for gemstone displays in the museum is an example of a GIS analysis. To answer your question, the software examined the database and map, and gave you the location of the gemstone exhibit. There is no fixed information to go with the map in a GIS. Some GIS show where power lines run, others show the roads, while others show schools.

GIS is important because of its ability to analyze information. Any information which is related to maps can be analyzed with a GIS. The types of maps and data in a GIS are also very flexible. A GIS map can cover very small to very large areas. A small GIS map might just show a few blocks in a city. It might show details of where utilities such as telephones lines, sewers, and cables are located. A large GIS map could cover the entire Earth. It might show seasonal changes in plant growth. The information that a GIS map shows can be about anything.

A geographic information system (orGIS) is a way of representing information about the world in a computer in the same way a map shows the world on paper.

What is a Topographic Map?

A map is a representation of the Earth, or part of it. The distinctive characteristic of a topographic map is that the shape of the Earth?s surface is shown by contour lines. Contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steepness of slopes.

A topographic map shows more than contours. The map includes symbols that represent such features as streets, buildings, streams, and vegetation. These symbols are constantly refined to better relate to the features they represent, improve the appearance or readability of the map, or reduce production cost.

Consequently, within the same series, maps may have slightly different symbols for the same feature.

Examples of symbols that have changed include built-up areas, roads, intermittent drainage, and some lettering styles. On one type of large-scale topographic map, called provisional, some symbols and lettering are hand- drawn.

Date: 2016-06-13; view: 450