Add tile statistics to mbtiles

[sharkAndshark]

Try to fix #964

• Add tile statistics to mbtiles tools
• Add test
• Use 4326 instead of 3857 for tile bounds
• Add document
• Use size-format to prettify output
• Statistics struct Refactor
• Cleanup and reformat

[nyurik]

P.S. It is usually better to use git merge main, rather than using rebase. Rebase tends to loose tracking of the review comments.

[sharkAndshark]

P.S. It is usually better to use git merge main, rather than using rebase. Rebase tends to loose tracking of the review comments.

Thx! Didn't know that before : )

[nyurik]

Forgot to mention - I am not certain if you are affected by this, but mbtiles invert the Y value (tile_row) -- the Y coordinate of a tile corresponds to 2^zoom - 1 - tile_row in mbtiles.

[sharkAndshark]

Thx for the mention. I did some research and I hope it's right.
MBTiles spec says it follow TMS, so the the Y of tile index increase from down to top.

Schema	Y
XYZ	From top to down
TMS	From down to top

Tile Origin and Bbox of 3857

Origin	Bbox
(-20037508.34, -20037508.34)	[-20037508.34, -20037508.34, 20037508.34, 20037508.34]

Length of one single tile

(20037508.34 * 2) / (2^zoom_level)

MinX,MaxX

MinX = OriginX + X * TileLength
MaxX = MinX + TileLength

MinY,MaxY

MinY = OriginY + Y * TileLength
MaxY = MinY + TileLength

[sharkAndshark]

Seems that PathBuf couldn't work with file:something?mode=memory together. Using sql query for the file size instead of PathBuf now. @nyurik

[nyurik]

yeah, seems reasonable. The alternative would be to have Option for the size, and set it to None if unable to get it from the filesystem.

[wipfli]

@bdon you did something similar for pmtiles, right?

[nyurik]

yeah, seems reasonable. The alternative would be to have Option for the size, and set it to None if unable to get it from the filesystem.

[nyurik]

no point for all this complex expect strings which will never happen. Might as well do a simpler variant:

Suggested change

	if self.count != 0 {
	let smallest = SizeFormatterBinary::new(self.smallest.expect("The smallest tile size of all zoom levels shouldn't be None when the tiles count of all zoom level is not 0"));
	let largest = SizeFormatterBinary::new(self.largest.expect("The largest tile size of all zoom levels shouldn't be None when the tiles count of all zoom level is not 0"));
	if let (Some(smallest), Some(largest)) = (self.smallest, self.largest) {
	let smallest = SizeFormatterBinary::new(smallest);
	let largest = SizeFormatterBinary::new(largest);

[sharkAndshark]

Is The largest tile size of all zoom levels shouldn't be None Ok? Or just "Couldn't be None".

[nyurik]

you don't need to do any asserts (.expected(...)) - you can simply check if both values are not None, and if so, use them.

[nyurik]

Awesome job, well done, thank you!!!

[sharkAndshark]

Awesome job, well done, thank you!!!

Thx all your guidance ！Hope I can do better in next : )