- Projection types illustrated
Because maps are flat, some of the simplest projections are made onto geometric shapes that can be flattened without stretching their surfaces. These are called developable surfaces. Some common examples are cones, cylinders, and planes. A map projection systematically projects locations from the surface of a spheroid to representative positions on a flat surface using mathematical algorithms.
The first step in projecting from one surface to another is creating one or more points of contact. Each contact is called a point (or line) of tangency. A planar projection is tangential to the globe at one point. Tangential cones and cylinders touch the globe along a line. If the projection surface intersects the globe instead of merely touching its surface, the resulting projection is a secant rather than a tangent case. Whether the contact is tangent or secant, the contact points or lines are significant because they define locations of zero distortion. Lines of true scale include the central meridian and standard parallels and are sometimes called standard lines. In general, distortion increases with the distance from the point of contact.
Many common map projections are classified according to the projection surface used: conic, cylindrical, or planar.
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FAQs
Your choice of a projected coordinate system depends on many factors, including the part of the world you are mapping, the scale of your map, and the purpose of your map. You want to choose a projected coordinate system in which the places and properties that are most important to your map are the least distorted.
What is the best projection type? ›
You should use an equal-area projection if you're mapping something that's fundamentally tied to area, such as crop acreage, population density, the size of empires, and so on. For maps of cities or small regions, the choice is easy: use the Mercator projection.
What type of projection is best for navigation? ›
Cylindrical Projection – Mercator
It became the standard map projection for nautical purposes because of its ability to represent lines of constant true direction. (Constant true direction means that the straight line connecting any two points on the map is the same direction that a compass would show.)
What are the three main common types of projection? ›
Map projections are a way of representing our spherical world on a flat surface by transferring longitude and latitude lines to X and Y coordinates. There are 3 main types of map projection; azimuthal, conical, and cylindrical. One of the most well-known map projections is the Mercator Projection.
What is the most commonly used projection? ›
The Mercator is the most popular conformal map projection. The Mercator map projection was created by Gerardus Mercator in 1594. It showed meridians as equally spaced lines. The projection is used for a variety of navigational plotting of ship routes.
What is the most common projection? ›
The most well-known map projection is the Mercator projection. This map projection has the property of being conformal. However, it has been criticized throughout the 20th century for enlarging regions further from the equator.
What are the different types of projection in computer graphics? ›
2 main types: perspective projection and parallel projection. perspective : center of projection finitely far from view plane. projectors will not be parallel to each other.
What software creates projection mapping? ›
HeavyM has simplified video mapping for thousands of artists and professionals with its exceptional ease of use, making complex projects accessible to all.
What projection does Google Maps use? ›
Google Maps use Mercator projection for browser-based maps. When Fusion creates a map that uses maps.google.com imagery as the source, it uses Google Maps projection for the rasterized vectors so that they match the underlying Google Map tiles. This EPSG code is EPSG:900913 or EPSG:3785.
What projection is best for mapping small areas? ›
For a regional map—a few counties, or even many smaller states—a UTM (Universal Transverse Mercator, not the same as a Mercator, confusingly) projection might be a good choice. One of the biggest advantages of a UTM is that measuring distances between two points is a snap.
The Robinson projection is unique. Its primary purpose is to create visually appealing maps of the entire world. It is a compromise projection; it does not eliminate any type of distortion, but it keeps the levels of all types of distortion relatively low over most of the map.
What are the 4 main map projections? ›
The four main types of map projections are conformal projection, equal-area projection, equidistant projection, and true direction projection, also called equal-angle projection.
What is perspective projection in computer graphics? ›
Perspective projection is a geometric technique used to produce a three dimensional graphic image on a plane, corresponding to what person sees. Any set of parallel lines of object that are not parallel to the projection plane are projected into converging lines.
Which map projection has no distortion? ›
The only 'projection' which has all features with no distortion is a globe. 1° x 1° latitude and longitude is almost a square, while the same 'block' near the poles is almost a triangle. There is no one perfect projection and a map maker must choose the one which best suits their needs.
How to find the correct coordinate system? ›
To identify the correct coordinate system, examine the extent of the dataset. Determine which type of coordinate system best matches the dataset's extent information, and visit the related article for that specific type of coordinate system. Examine the coordinate extent of the dataset.
What projection is best for North America? ›
Conic projections are particularly useful for mid-latitude regions with primarily East-West extent, such as the United States. Figure 5.7. 1 Lambert conformal conic, with a standard parallel at 60N.
How to select a coordinate system? ›
Choose a coordinate system from a list
- In the Contents pane, right-click the map or scene and click Properties.
- On the Map Properties dialog box, click the Coordinate Systems tab. ...
- To change the horizontal or vertical coordinate system, click the button below the Current XY or Current Z heading, respectively.
In an orthographic drawing, the right side view of the object is usually shown in the lower right, the front view is usually shown in the lower left, and the top view is usually shown in the upper left.
