Timeline for What is the difference for a shapefile line feature length between "Cartesian" and "ellipsoid"
Current License: CC BY-SA 4.0
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| Jan 26, 2022 at 17:45 | comment | added | Michiel Rademakers | @StuSmith: the problem is related to the Mercator Projection. Cartesian calculations are performed on the virtual map cylinder which is "way out in space". Modern Transverse Mercator uses a small cylinder touching the poles, so that the x value is precise, and the y error minimal. The old geographers of the USGS solved the problem by using the Polyconic Projection, which attributes each map its own dedicated little map plane. | |
| Jan 26, 2022 at 17:36 | history | edited | Michiel Rademakers | CC BY-SA 4.0 |
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| Jan 26, 2022 at 16:10 | comment | added | Stu Smith | Good work. Is there any chance that you can add a graphic or screenshot to your answer that will illustrate what you described? Also, is your problem limited to just EPSG:3857, or all CRSs? Finally, can you draw some conclusions, such as "Here's when to use Cartesian, and here's when to use ellipsoid". | |
| Jan 26, 2022 at 14:29 | history | edited | Michiel Rademakers | CC BY-SA 4.0 |
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| Jan 26, 2022 at 14:20 | history | answered | Michiel Rademakers | CC BY-SA 4.0 |