Scales & Series
The most popular and the most detailed are the 7.5-minute or 1:24,000-scale (1 inch = 2,000 feet) quadrangle series. Depending on latitude, the area portrayed by the 7.5-minute series ranges from 49 to 64 square miles. It takes about 57,000 7.5-minute maps to cover the 48 contiguous states.
Why is a 7 1 2 minute map a quadrangle rectangle instead of a square?
These quadrangles are not squares because 7.5′ of longitude is a smaller distance in miles at 36° N (36th parallel) than 7.5 minutes of latitude.
What is a 7 1 2 minute map?
Quadrangle maps or quads are a type of topographic map produced by the United States Geological Survey (USGS) that divides the United States into areas or quadrangles bounded by lines of latitude and longitude. These maps have two distinctive features: 7.5-minute length and breadth at a 1:24,000 scale.
What is a 7.5 minute quadrangle
USGS topographic maps have been published at many scales, but 1:24,000 (also referred to as a 7.5-minute quadrangle) has been the standard topographic map scale since 1947. For Alaska the standard scale is 1:25,000.
What does 7.5 mean on a map
7.5 minute maps are so called because each covers 7.5 minutes of latitude and 7.5 minutes of longitude on the earth’s surface. On the ground, this is approximately equal to eight miles (north and south) by six miles (east and west).
What is a minute on a map
One degree of latitude equals approximately 364,000 feet (69 miles), one minute equals 6,068 feet (1.15 miles), and one-second equals 101 feet.
What is the most common contour interval for 7.5 minute maps
Contours are placed at regular vertical intervals, usually 20 feet, though they may also represent 5- 10- or 40-foot (1.5- 3.1- or 12.2-meter) intervals on a 7.5 minute quadrangle, with a bolder lined index contour every fifth line, or 100 feet, to facilitate orientation.
Why is the Yakima East quadrangle called a 7.5 seven and one half minute map
The maps produced at a 1:24,000 scale (1 inch represents 24,000 inches or 2000 feet) are commonly known as 7.5-minute quadrangle maps; each map covers 7.5 minutes of latitude and 7.5 minutes of longitude, which is approximately 8 miles (north/south) and 6 miles (east/west).
Why use flat maps instead of Globes
Maps can show very large areas or very small areas. Also, maps are flexible tools that can provide large amounts of information very efficiently. Maps are not as accurate as globes, however. To create a flat representation of Earth’s curved surface, something has to be distorted.
What is the golden rule for map reading
You have probably now learned the Golden Rule of map-reading and navigation, the biggest single tip for success, which we call orientating the map. This means holding the map in such a way that the features on the map and the features in the real world are all lined up and pointing the same way.
What is a 1 50000 map called
A graphical or bar scale. A map would also usually give its scale numerically (“1:50,000”, for instance, means that one cm on the map represents 50,000cm of real space, which is 500 meters) A bar scale with the nominal scale , expressed as both “1cm = 6km” and “1:600 000” (equivalent, because 6km = 600 000cm)
What are the 3 types of scale map
There are three types of scales commonly used on maps: written or verbal scale, a graphic scale, or a fractional scale. A written or verbal scale uses words to describe the relationship between the map and the landscape it depicts such as one inch represents one mile.
What is the most accurate elevation map?
The Swiss Federal Office of Topography (SwissTopo) is world-renowned for its accuracy, quality and artistry.
Why isn’t zero at the far left of the scales
Why isn’t “0” far left of the scales? It’s not on the far left side because it wouldn’t allow us to be much more precise if it was at the far end. Being where it is, it gives us a closer approximation to the actual distance in the real world.
What is the best topo map
With more than 14,000 reviews in the App Store and Google Play, onX Hunt is the best topo map app.
What is the ratio scale for a typical 7.5 minute quadrangle
The best known USGS maps are those of the 7.5-minute, 1:24,000-scale quadrangle series. A scale of 1:25,000 is used for maps based on metric units (1 centimeter = 0.25 kilometer).
What does a scale of 1 100 mean
Ratio scales
If the scale of the plan is 1 : 100, this means the real measurements are 100 times longer than they are on the plan. So 1 cm on the plan represents a real length of 100 cm (1 metre)
What is a scale of 1 500
A scale of 1:500 means that the actual real-life measurements are 500 times greater than those on the plan or map. This means that it does not matter whether you take the measurements on the plan in millimetres (mm), centimetres (cm) or metres (m) – the measurements will be 500 times as much in real life.
How do you find the ratio scale
To find the scale factor, locate two corresponding sides, one on each figure. Write the ratio of one length to the other to find the scale factor from one figure to the other. In this example, the scale factor from the blue figure to the red figure is 1.6 : 3.2, or 1 : 2.
How do you read a 7.5 minute USGS map
Traditional 7.5 Minute Topographical Map
Note: a minute is one 60th of a degree, and not a measure of time. 7.5 Minute refers to the fact the map covers an area 7 minutes and 30 seconds of longitude by 7 minutes and 30 seconds of latitude. The title of the map is indicated in the upper right hand corner.
What does a 15 minute map mean?
15-minute maps
The standard map series covering Alaska is the 15-minute, 1:63,360-scale (1 inch = 1 mile) quadrangle series, usually having dimensions of 15 minutes in latitude and from 20 to 36 minutes of longitude. The area portrayed on each sheet ranges from 207 to 280 square miles, depending on the latitude.
Why is latitude measured in minutes
Latitudes and longitudes are measured in degrees (°) because they represent angular distances. Each degree is further divided into 60 minutes ( ‘ ) and each minute into 60 seconds ( “ ).
How many minutes is 1 degree longitude
Each degree can be divided into 60 minutes, and each minute is divided into 60 seconds.
What is a good contour interval?
The commonly used contour interval is 20 feet for a 1:24,000 map scale.
How contour interval is decided
A contour interval is the vertical distance or difference in elevation between contour lines. Index contours are bold or thicker lines that appear at every fifth contour line. If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing.
How accurate are topo maps
The orthoimage layer in US Topo maps is derived from images of the National Agriculture Imagery Program (NAIP). The production of these images is well controlled; they have an accuracy of 6 meters (~20 feet) or better.
Why is it called Yakima
Nobody really knows for sure how Yakima got its name. Of the many theories about the origins of the city’s name, one of the more popular is based on a legend about an Indian chief’s daughter who fled from her home after she broke tribal rules. The chief’s daughter made her home along the river named Yakama.
Why is Yakima called Yakima?
The name Yakima originates from the Yakama Nation Native American tribe, whose reservation is located south of the city.
What does a 1 24000 map mean
For example, a map scale indicating a ratio of 1:24,000 (in/in), means that for every 1 inch on the map, 24,000 inches have been covered on the ground. Ground distances on maps are usually given in feet or miles.
Why is Africa small on maps
The world map you are probably familiar with is called the Mercator projection (below), which was developed all the way back in 1569 and greatly distorts the relative areas of land masses. It makes Africa look tiny, and Greenland and Russia appear huge.
What is the most accurate map projection
AuthaGraph. The AuthaGraphy projection was created by Japanese architect Hajime Narukawa in 1999. It is considered the most accurate projection in the mapping world for its way of showing relative areas of landmasses and oceans with very little distortion of shapes.
Which is more accurate a map or a globe
Maps provide more information than a globe. A globe can be useful when we want to study the earth as a whole. But when we want to study only a part of the earth, as about a country or a state, globe is of little help. In such a situation only maps are useful.