One distortion seen on common world maps is the relative scale of land masses. In fact, all 2D world maps are wrong to some degree (In fact, a sphere’s surface cannot be represented on a flat surface without distortion.) The cost of this transformation means some map projections are distorted. So, to represent our 3D earth with an accurate scale on 2D paper (or screen), map projections are used. What is a map projection?Ī map projection is defined as a systematic transformation of the coordinates (latitude and longitude) on the surface of a sphere (or ellipsoid) into plane coordinates on a flat surface (x, y).Įarth is spherical, existing in three dimensions. Once it’s set, all work must be done within the chose coordinate system for the duration of the project. Surveyors setting up a work site will chose the best coordinate system to use for the worksite’s location, before any building is started. Many geographic and projected coordinate systems are used around the world. How coordinate systems are chosen for a worksite Distortion can happen within an angle, area, direction, or distance because it’s impossible to completely flatten a spherical surface (like the earth’s terrain). For example, a local grid can be as small as the size of a single site, which reduces projection distortion considerably. Projected coordinate systems can be more useful for worksites over geographic coordinate systems because they have less local distortion. National and local grids are examples of projected coordinate systems. Geographic coordinate systems are three-dimensional grids, while projected systems use map projections to view the world as a two dimensional map. Technically, there are two classes of coordinate reference systems: geographic and projected coordinate systems. Image via Wikimedia Commons/djexplo Projected vs. Knowing this information lets you determine where you (or your worksite) are on the earth. Think of it this way: coordinate systems provide X, Y, Z, locations for all points on a land surface. It’s a system that defines the location of a point on a plane or sphere. When you see the term coordinate system, it’s referring to what’s more precisely called a coordinate reference system. Why the world uses many coordinate systems.How coordinate systems are chosen for a worksite.Plus, we’ll explain the importance of why transforming between different coordinate systems is necessary– and how to make it easier. To help you understand, we’ll explain the difference between coordinate systems and map projections, the difference between projected and geographic coordinate systems, and other topics that will help you obtain accurate, actionable survey measurements for your jobsite. Furthermore, operating smart ground control points (GCPs) like AeroPoints only requires the push of a button.īut tackling geographic coordinate systems and map projections, can be a little more complicated. Learning to fly the Phantom 4 RTK takes a relatively short amount of time, and obtaining your Part 107 license is easier than you may think. As drones become more commonplace in construction surveying workflows–and as they become more accessible to small- and medium-sized civil construction and earthworks businesses–understanding topics like coordinate reference systems, map projections, and local grids is becoming more important for a variety of roles responsible for managing site work.ĭrone surveying is straightforward to grasp with some hands-on experience and training.
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