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I would like to create a 3meter x 3meter Raster Grid on a Worldmap in QGIS. I am fairly new to the whole topic but I have found out that the equirectangular projection should be the most accurate, like displayed here

enter image description here

I am currently using MMQGIS to draw grids but I have problems finding the right granularity and rendering it on the whole map. How can I make sure I am getting 3mx3m grids and which world map should I download?

I later want to index each rectangle and from my calculations there should be about 57 Trillion is that correct?

510 * 10^14 (size of world) / 9m2 (size of grid) := 5.667 * 10 ^13 := 57 Trillion

closed as too broad by Vince, Jochen Schwarze, LaughU, whyzar, xunilk Feb 22 at 4:40

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    It took a good deal of effort to generate a 5km × 5km vector grid (aka fishnet) in decimal degrees over landforms (and nearby coastal waters) -- reaching 17 million features. Working with this grid is difficult. I also generated 1km x 1km for limited study areas, and had difficulty keeping the unique Id's under 2.1 billion. I can assert that managing a 3m x 3m fishnet is insane. – Vince Feb 21 at 0:19
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    By your own calculations your mesh contains 57 trillion cells. For every byte of information per cell, you will need 57 terabytes of storage. As @Vince remarks, this is insane. (Unless of course you own a datacenter scale server and storage farm. ) – Llaves Feb 21 at 4:23
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    however, to get the same visual effect for the world map, just change your QGIS canvas color to black...,) – ThingumaBob Feb 21 at 8:32
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    I agreed with the "insanity" comment, but then remembered that What3Words uses a 3m grid over the entire Earth. I guess they're using a database of text terms, rather than a raster or vector grid, which shows the sort of approach you need to take for a project of this scale. – Mark Ireland Feb 21 at 16:12
  • You can add a grid as a map canvas "decoration" from the View menu. That would just be for display, it wouldn't exist as a layer. – csk Feb 21 at 17:46