Timeline for Create polygon grid based on spatial points (WGS84) with R
Current License: CC BY-SA 4.0
8 events
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| Jul 10, 2021 at 17:32 | comment | added | Maxime Garnault | That is indeed much better. With your handmade grid the mean distance between true centroids and estimated centroids ranges from 0 to 5m (in Lambert II, as in WGS84), with an average offset of 2.17m. Therefore I will not use the points2grid() method after all... Thanks a lot for your help ! | |
| Jul 9, 2021 at 23:42 | comment | added | FSimardGIS | I'm not sure exactly how the points2grid algorithm works, but when I tested, I made a new grid with this method, but with the size and extent parameters that I mentioned above, and in Lambert II. Then I checked the distances in Lambert II as well, and all the points were within 3 meters, more or less, of the grid centroids. I would try it with that kind of simple grid, it might give you better results, since from my observations and test, I know it closely matches that specific grid. | |
| Jul 9, 2021 at 20:21 | comment | added | Maxime Garnault | Could this difference be due to the fact that I computed distances in the initial projection (WGS84), while you did in the Lambert II projection ? Or did you spot an error in my code (such as when I used the point2grid() function that I am not very familiar with) ? Also, I am curious about how you generated your grid “from scratch” as you said ? | |
| Jul 9, 2021 at 17:46 | comment | added | FSimardGIS | Interesting. When I tested it on my side, the errors were more in the range of 2-3 meters. The points really closely matched a regular grid. But I generated my grid from scratch in epsg:27572, not with the points to grid function. The grid was 8000 x 8000, with a range of (0, 1240000, 1605000, 2685000) | |
| Jul 9, 2021 at 15:55 | history | edited | Maxime Garnault | CC BY-SA 4.0 |
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| Jul 9, 2021 at 15:48 | history | edited | Maxime Garnault | CC BY-SA 4.0 |
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| Jul 9, 2021 at 14:54 | history | edited | Maxime Garnault | CC BY-SA 4.0 |
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| Jul 9, 2021 at 14:44 | history | answered | Maxime Garnault | CC BY-SA 4.0 |