readme revisions

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Brandon Liu
2021-04-15 10:50:28 +08:00
parent a31abbb56f
commit c1c4561a9d

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@@ -31,7 +31,9 @@ Example of a raster PMTiles archive decoded and displayed in Leaflet:
## Specification ## Specification
PMTiles is a binary serialization format designed for two main access patterns: over the network, via HTTP 1.1 Byte Serving (`Range:` requests), or via memory-mapped files on disk. All integer values are little-endian ![layout](layout.png)
PMTiles is a binary serialization format designed for two main access patterns: over the network, via HTTP 1.1 Byte Serving (`Range:` requests), or via memory-mapped files on disk. **All integer values are little-endian.**
A PMTiles archive is composed of: A PMTiles archive is composed of:
* a fixed-size 512,000 byte header section * a fixed-size 512,000 byte header section
@@ -56,8 +58,6 @@ An entry consists of:
* 6 bytes: the offset of where the tile begins in the archive. * 6 bytes: the offset of where the tile begins in the archive.
* 4 bytes: the length of the tile, in bytes. * 4 bytes: the length of the tile, in bytes.
![layout](layout.png)
### Notes ### Notes
* A full directory of 21,845 entries holds exactly a complete pyramid with 8 levels, or 1+4+16+64+256+1024+4096+16384. * A full directory of 21,845 entries holds exactly a complete pyramid with 8 levels, or 1+4+16+64+256+1024+4096+16384.
* A PMTiles archive with less than 21,845 tiles should have a root directory and no leaf directories. * A PMTiles archive with less than 21,845 tiles should have a root directory and no leaf directories.