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- 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. Map global analysis results Map projections distort the grid of latitude and longitude lines, which means they also distort your data.
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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. Map global analysis results. Map projections distort the grid of latitude and longitude lines, which means they also distort your data.
Linear distortion. Difference in distance between a pair of projected (map grid) coordinates when compared to the true horizontal (“ground”) distance, denoted here by δ. Can express as a ratio of distortion length to ground length: E.g., feet of distortion per mile; parts per million (= mm per km).
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The Scale Factor is a measure of the distortion associated with a projected coordinate system. It is the ratio of the measured scale to the true scale at any location on a map. A scale factor of one (SF = 1) means there is no distortion.
Summary. Projections transform geographic coordinates (f, l) to cartesian (x, y). Projections distort distance, area, direction and shape to greater or lesser degrees; choose projection that minimizes the distortion of the map theme. Points of tangency, standard parallels and secants are points or lines of no distortion.
- Where: Geographic Coordinate Systems
- How: Projected Coordinate Systems
- Coordinate System Construction
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- Summary
You are part of a search and rescue team looking for an injured person in the Australian outback. The point location you have from her satellite phone is 134.577°E, 24.006°S. Where is she located? Both location A and B in the above image are correct. A is 134.577°E, 24.006°S in one GCS (Australian Geodetic Datum 1984) and B is the same coordinate l...
Once your data knows where to draw, it needs to know how. The earth’s surface—and your GCS—are round, but your map—and your computer screen—are flat. That’s a problem. You can’t draw the round earth on a flat surface without deforming it. Imagine peeling an orange and trying to lay the peel flat on a table. You can get close, but only if you start ...
In ArcGIS Pro, you can view the details of any coordinate system in the Map Properties window, on the Coordinate Systems tab. Click the green Detailslink. The image below shows the Details page for the Fuller (world)coordinate system: 1. The first line tells you that it’s a Projected Coordinate System, as opposed to a GCS. 2. A PCS, by definition, ...
Can’t we choose a GCS for our map instead of a PCS? I’ve made maps before that were in WGS 1984and they drew just fine, didn’t they? Let’s try it out. In Map Properties, expand the Geographic Coordinate System list and choose any one. Click OK. Your map will look like this, regardless of which GCS you chose: Remember that it is impossibleto draw th...
You can store your data in a GCS. But you can’t draw it on a flat map without a PCS.The GCS tells your data where to draw. The PCS tells the map how to stretch the GCS out flat.Which GCS you choose depends on where you are mapping.Which PCS you use depends on where you are mapping, but also the nature of your map—for example, should you distort area to preserve angles, or vice versa?Map projections are sets of mathematical models which transform spherical coordinates (such as latitude and longitude) to planar coordinates (x and y). In the process, data which actually lie on a sphere are projected onto a flat plane or a surface. That surface can be converted to a planar section without stretching.
May 21, 2023 · Moreover, such projections distort distances as well as angular relationships. As noted earlier, there is theoretically an infinite number of map projections to choose from. One of the key considerations behind the choice of map projection is to reduce the amount of distortion.
