Timeline for Map projection classification - Tissot's indicatrices are perfect circles, but the projection is not conformal
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Mar 1, 2017 at 17:01 | answer | added | pnz1337 | timeline score: 0 | |
| Feb 22, 2016 at 11:56 | comment | added | Aleksandar | According to the original question, I have to confirm that the problem is solved. Namely, for the OSC projection Tissot's indicatrices are always rotated for +/-45 degrees. That causes the lines that lie along the axes in the projected space always transform to equal-length lines on the globe (they cross the ellipse at the same distance). That led me to a wrong conclusion that indicatrices are circles, but they are not. I tested the projections for millions of points across the projection plane and it was expensive to check every possible direction. However, it was a very wrong decision. :( | |
| Feb 22, 2016 at 9:53 | history | tweeted | twitter.com/StackGIS/status/701706426104811520 | ||
| Feb 21, 2016 at 19:28 | history | edited | PolyGeo♦ | CC BY-SA 3.0 |
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| S Feb 21, 2016 at 15:13 | history | suggested | Aleksandar | CC BY-SA 3.0 |
Adding details needed to clarify the question.
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| Feb 21, 2016 at 13:22 | review | Suggested edits | |||
| S Feb 21, 2016 at 15:13 | |||||
| Feb 20, 2016 at 23:58 | answer | added | Martin F | timeline score: 1 | |
| Feb 20, 2016 at 23:56 | comment | added | Martin F | Welcome to GIS SE! How do you calculate angular distortion, exactly? If the Tissot indicatrices are circles everywhere, you have conformality. Conformality, however, only preserves angles at points on the globe -- not between arbitrary straight lines on the projected surface. | |
| Feb 20, 2016 at 19:57 | history | edited | PolyGeo♦ | CC BY-SA 3.0 |
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| Feb 20, 2016 at 19:09 | comment | added | mkennedy | Is there some reason why you're not naming the projection? Are you calculating the TIssot parameters with code you wrote or via other software? | |
| Feb 20, 2016 at 12:11 | review | First posts | |||
| Feb 20, 2016 at 15:08 | |||||
| Feb 20, 2016 at 12:10 | history | asked | Aleksandar | CC BY-SA 3.0 |