Evaluation Of Map Projection Distortion
Figure 1. Elementary circle in the tangent plane on the sphere , and corresponding ellipse of distortion in the mapping plane .
10Acknowledging that map projection distortion can present itself in many different ways , some authors have also proposed the use of combined distortion measures, which provide a general assessment of the combined impact of two, three or even more different aspects of distortion. Some of these measures, especially those referring to various aspects of distortion at the local scale, already have a long history , others have been proposed more recently . One of the major difficulties in the definition of combined distortion measures is that not all aspects of distortion are expressed in the same units, and therefore cannot be directly compared. Overcoming this problem requires that measurements of different aspects of distortion are properly calibrated. Only recently Laskowski proposed a method for the standardisation of different distortion measurements that offers a partial solution to the problem of unlike units. However, the more fundamental problem of weighting different aspects of distortion equally is far from solved and remains an interesting area for future research.
Example Question #: Ap Human Geography
Ethnocentrism primarily involves __________.
ostracizing minority groups within a society through a series of legal and political machinations
forcibly spreading oneâs culture to neighboring countries
judging a foreign culture by the standards of oneâs own culture
protecting minority groups within a society through a series of legal and political machinations
None of these answers is correct.
judging a foreign culture by the standards of oneâs own culture
âEthnocentrismâ is based on the belief that oneâs own culture is inherently superior and that other nations are backwards or underdeveloped because their culture is different. It primarily involves judging a foreign culture by the standards of oneâs own culture. It can involve the forced spread of oneâs own culture, but it does not have to, it is enough simply to judge another culture by the standards of your own.
Spanish and Portuguese
natural scenic wonder and beauty
its readily apparent biological diversity
use of artificial elements to create a natural-looking environment
its religious significance for Muslims, Christians, and Jews
housing of politically significant institutions
its religious significance for Muslims, Christians, and Jews
What Causes Spatter In Welding
Spatter is caused by several factors. The main factor is a disturbance in the molten weld pool during the transfer of wire into the weld. … In this situation, the arc is too cold to keep the wire and pool molten and causes a stubbing effect of the wire. This can occur at both high and low current ranges.
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Universal Mercator Grid System
Although latitude and longitude and the Public Land Survey are the most often used system for determining locations on the earth, a third method, which is somewhat more complicated, called the Universal Tranverse Mercator Grid System, is also shown on most topographic maps published by the USGS. This is based on the transverse Mercator projection and covers the earth’s surface between 80 south and 84 north latitudes.
The UTM system involves establishing 60 north-south zones, each of which is six degrees longitude wide. In addition, each zone overlaps by two degrees into adjoining zones. This allows easy reference to points that are near a zone boundary, regardless of which zone is in use for a particular project. Each UTM zone is assigned a number. Grid zone 1 is assigned to the 180 meridian with zones numbered consecutively eastward. A false origin is established 500,000 m west of the central meridian of each UTM zone. In the Northern Hemisphere, this origin is on the equator in the Southern Hemisphere it is 10,000,000 m south of the equator. A square grid, with lines extended north and east from the origin, provides a basic locational framework. With this framework, any point on the earth’s surface, within each zone, has a unique coordinate. UTM coordinates are shown on the edges of many USGS topographic maps.
M.F. Goodchild, in, 2009
Compromises Do Nothing Perfect But Most Things Well Enough
If you skim through the example images above, you may notice that, as a general trend, distortions tend to get worse and worse as you get near the edges of the map. Thereâs usually one area that looks alright and isnât too distorted, and then things start to get crazy the farther you move away from that area. As an example, on the Azimuthal Equidistant above, Australiaâs shape gets distorted heavily, but the British Isles look fine. As a general rule, the larger the area your map shows, the worse distortions will be, especially as you move away from the center. What all this means is that we are most worried about distortions when we are doing things like mapping the world, and less when we are mapping smaller areas like cities or states.
To solve the problem of world maps having such severe distortions at the edges, people have come up with compromise projections. These special projections represent trade offs: while most projections have minimal distortion in one area but distort heavily as you move away from that area, compromise projections distort a moderate amount everywhere. The Robinson projection is one example of a compromise projection:
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What Is Slumping In Geography
Correspondingly, what is slumping and sliding?
Slumps and slides are downslope movements of sediments above a basal shear surface where there is, respectively, significant and insignificant internal distortion of the bedding . In slumps, the bedding should be recognizable, otherwise they classify as debris flows.
Secondly, what is sliding in geography? Slides. A slide happens when a section of soil or rock suddenly gives way and moves down a slope. The material moves as a single mass along a slippery zone. The slippery zone is often made up of wet sediment . Translational slides move along a flat slippery zone.
Then, what is slumping GCSE?
Slumping: involves a whole segment of the cliff moving down-slope along a saturated shear-plane.
What is a rockfall in geography?
Rockfall is a form of mass movement or mass wasting in which pieces of rock travel downward through some combination of falling, bouncing, and rolling after they are initially separated from the slope.
Utm Map Grid And The Australian Map Grid
As is explained in the section tiled Explaining Some Jargon Graticules and Grids there is a significant difference between the two.
- Graticules are lines of Longitude and Latitude. These never form a square or rectangular shape and their shape changes dramatically from the Equator to the Pole from being close to square shaped to being close to triangle shaped.
- Grids are a regularly shaped overlay to a map. They are usually square, but they may be rectangular.
Grids rarely run parallel to lines of Longitude and Latitude.
Besides ease of use, there is another advantage to a grid on any given map it always covers the same amount of the Earths surface. This is not true of a graticule system! A 1° x1° block of latitude and longitude near the Equator will always cover vastly more of the Earths surface and a 1° x1° block closer to a Pole. Therefore it is easy to measure distances using a grid it removes the foibles of distortions inherent in each map projection.
When NATO created the UTM system it recognised this fact and built a grid system into it. This involves a regular and complex system of letters to identify grid cells. To identify individual features or locations distances are first measured from the west to the feature and then measured from the south to the feature. The three are combined to give a precise location based on the map grid.
Explaining some jargon:
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Section Seven: Projected Coordinate Systems
In the last three sections, we looked how reference ellipsoids are combined with geoids via control points to create datums and how geographic grids utilize an angular unit of measure to label intersections of north-south and east-west lines starting at a principal meridian, examining the latitude/longitude system as an example. We then learned that combining a specific datum with a geographic grid creates an accurate way to locate those labeled points utilizing the geographic coordinate system. In this final section, we will look at the final concept that connects geodesy to GIS: projected coordinate systems.
While it is possible to use a geographic coordinate system in the GIS and print a map showing angular units, this system doesnt make a ton of sense in our minds. If I told you the area of a particular place was 0.00034 degrees squared, how big is that? As big as Rhode Island or as big as Texas? You most likely have no idea. If I gave you directions to my house by saying travel along Main Street at a heading of 270 for 0.029 degrees latitude and make a left on 9th. Youll find my house at 2 0859.96 N, 110 5009.03W, you most likely would have a tough time trying to find it without the use of a GPS app or receiver. Overall, we do not perceive the world in angular units, but instead by linear units – the area of a place is 1 mile square or you tell people to ‘head 2 miles west on Main and turn right on 9th’.
What Can Be Remedies Of Gas Inclusion And Distortion
- Clean the materials before you begin welding.
- Use dry electrodes and materials.
- Use correct arc distance.
- Check the gas flow meter and make sure that it’s optimized as required with proper with pressure and flow settings.
- Reduce arc travel speed, which will allow the gases to escape.
- Use the right electrodes.
Metric Properties Of Maps
Many properties can be measured on the Earth’s surface independently of its geography:
Map projections can be constructed to preserve some of these properties at the expense of others. Because the Earth’s curved surface is not isometric to a plane, preservation of shapes inevitably requires a variable scale and, consequently, non-proportional presentation of areas. Similarly, an area-preserving projection can not be conformal, resulting in shapes and bearings distorted in most places of the map. Each projection preserves, compromises, or approximates basic metric properties in different ways. The purpose of the map determines which projection should form the base for the map. Because maps have many different purposes, a diversity of projections have been created to suit those purposes.
Another consideration in the configuration of a projection is its compatibility with data sets to be used on the map. Data sets are geographic information their collection depends on the chosen datum of the Earth. Different datums assign slightly different coordinates to the same location, so in large scale maps, such as those from national mapping systems, it is important to match the datum to the projection. The slight differences in coordinate assignation between different datums is not a concern for world maps or those of large regions, where such differences are reduced to imperceptibility.
Other distortion metrics
Distance Most Projections Distort Distances
A trip from Madison to Buenos Aires is much farther than a trip from Madison to Madrid. But on an Equirectangular projection, both of those trips looks like theyâre the same length, because this is a projection that does not preserve distance. On the other hand, the Azimuthal Equidistant projection shows distances in the correct proportion.
Thereâs a catch, though. While we have map projections that can preserve areas or form everywhere on the map, there isnât one that can preserve distances everywhere. There are only projections that let you preserve distances relative to just one or two points on the map. Distances to and from the center of an Azimuthal Equidistant map are shown correctly, but distances between any other two points are distorted. When a projection preserves distance, we call it equidistant.
The properties of area, distance, and form are mutually exclusive. If you have a map projection that preserves one, it will distort the other two
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What Are Map Projections
Latitude and longitude coordinates specify positions in a spherical grid called the graticule . The true geographic coordinates called unprojected coordinate in contrast to plane coordinates, like the Universal Transverse Mercator and State Plane Coordinates systems, that denote positions in flattened grids. These georeferenced plane coordinates are referred to as projected. The mathematical equations used to project latitude and longitude coordinates to plane coordinates are called map projections. Inverse projection formulae transform plane coordinates to geographic. The simplest kind of projection, illustrated below, transforms the graticule into a rectangular grid in which all grid lines are straight, intersect at right angles, and are equally spaced. Projections that are more complex yield grids in which the lengths, shapes, and spacing of the grid lines vary. Even this simplest projection produces various kinds of distortions thus, it is necessary to have multiple types of projections to avoid specific types of distortions. Imagine the kinds of distortion that would be needed if you sliced open a soccer ball and tried to force it to be completely flat and rectangular with no overlapping sections. That is the amount of distortion we have in the simple projection below .
Map Projections And Distortion
All indicatrices are circles area distortion varies with latitude. The Sinusoidal projection preserves area. All indicatrices enclose the same area. shapes are obliquely distorted. The Equal-Area Cylindrical projection also preserves area. Shapes are distorted from north to south in middle latitudes and from east to west in extreme latitudes.
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What Is Distortion In Music When And How To Use It
Explore the future of mastering:
Distort, mangle, transform, and more:
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This article references previous versions of Ozone. Learn about the latest Ozone and its powerful new features like Master Rebalance, Low End Focus, and improved Tonal Balance Control by clicking here.
Music production software has limits for how loud an audio signal can be. If an audio signal exceeds these limits, it will distort and produce a raspy, loud sound that makes most people reach for their ears.
Unwanted distortion has a negative impact on mix quality. But it also has many musical uses when introduced with intent. It brightens synths and guitars, lends heft to drums, and supplies dull sounds with the right amount of attitude.
Were in a peak moment for distortion as both a musical effect and aesthetic. Crunchy house and hip-hop tracks affixed with the descriptor lo-fi are riding a strong wave of blog buzz. DIY labels release cassette tapes. Even pop vocals are getting the distortion treatment.
In this article, Ill show you how to creatively use distortion in your DAW, along with audio examples.
Choose The Right Synonym For Distort
deform, distort, contort, warp means to mar or spoil by or as if by twisting. deform may imply a change of shape through stress, injury, or accident of growth. a face deformed by hatred distort and contort both imply a wrenching from the natural or normal, but contort suggests a more involved twisting and a more grotesque and painful result. the odd camera angle distorts the figure disease had contorted her body warp indicates an uneven shrinking that bends or twists out of a flat plane. warped floorboards
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Projection Methods To Reduce Specific Distortion
Certain projections are designed to reduce specific error throughout a map. Starting with the developable surfaces, we will look at five of the more common methods used to reduce specific distortion: equal area, conformal, equidistant, true direction, and compromise.
The goal of equal area maps, as the name suggests, is to create a map where each of the land masses represented is given an equal amount of area. Equal area projections are useful where relative size and area accuracy of map features is important , as well as for showing spatial distributions and general thematic mapping such as population, soil and geological maps.
In the image to the right, the map is covered by a series of orange ellipses, called distortion ellipses. Distortion ellipses, known as Tissots indicatrix, start a circles placed on the globe. As the projection is created, the distortion ellipses distort in a manner equal to the maps distortion at the place upon which they are centered. This method allows for a user to visualize the maps distortion without any measuring equipment. Distortion ellipses do not show up on the final map they are for visualization purposes only. When we examine the distortion of the ellipses, the shape is distorted, but the area remains constant throughout. This tells us that area is the factor being preserved.
|Figure 2.28: Gall-Peters cylindrical equal-area projection|
|Figure 2.29: Mercator – conformal projection|
What Is Wrong With The Peters Projection
It replaces the traditional Mercator map style that many of us are familiar with. The Gall-Peters map shows the correct sizes of countries, but it also distorts them. Countries are stretched horizontally near the poles and vertically near the Equator, so although the size may be right, the shape definitely isnt.
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What Four Things Do Map Projections Distort
There are four basic characteristics of a map that are distorted to some degree, depending on the map projection used. These characteristics include distance, direction, shape, and area.
My article is not to discuss the benefits of map projections but to look at how technology is contributing to skills and knowledge being lost.
What four things do map projections distort?
As a cartographer with over 25 years experience in the GeoSpatial Industry, I guess I have a slightly more critical eye when I see maps that are produced these days. It makes me cringe when I see maps that are missing some essential items like a scale, north point, legends, projection information or title. It is so easy these days to just press the print button and have the software spit out the map. It may portray the data in the way the cartographer indented but it looses basic usability outside the original production when it does not have these basic elements.
Are these basic elements being lost because it does not matter anymore or is it too easy to just rely on the technology and therefore too easy to overlook the basic elements. I feel it is more about the technology, although I do see there appears to be less importance placed on some of these at some levels of education.