Crate geocog 

geocog - Pure Rust COG (Cloud Optimized GeoTIFF) Reader

A high-performance library for reading Cloud Optimized GeoTIFFs without GDAL.

Features

• Metadata-only initialization: Reads only IFD headers (~16KB) on open
• Range requests: Efficient partial reads from local files, HTTP, or S3
• Streaming: Never loads entire file into memory
• Compression: Supports DEFLATE, LZW, ZSTD, and uncompressed
• Overviews: Automatic pyramid level selection with data density validation
• Coordinate transforms: Built-in proj support for CRS transformations

Example

use geocog::CogReader;

let reader = CogReader::open("path/to/file.tif")?;
let tile_data = reader.read_tile(10, 512, 384)?;

Architecture

The library is organized into several modules:

• cog_reader: Core COG metadata parsing and tile reading
• [cog]: High-level processing pipeline with caching
• range_reader: Abstraction for reading byte ranges from various sources
• s3: S3-compatible storage backend
• tile_cache: LRU cache for decompressed tiles
• raster: Raster data abstraction trait

Re-exports

pub use cog_reader::CogReader;

pub use cog_reader::CogMetadata;

pub use cog_reader::CogDataType;

pub use cog_reader::Compression;

pub use cog_reader::GeoTransform;

pub use cog_reader::OverviewMetadata;

pub use range_reader::RangeReader;

pub use raster::RasterSource;

pub use s3::S3Config;

pub use s3::S3RangeReaderAsync;

pub use s3::S3RangeReaderSync;

pub use tile_cache::TileCache;

Modules

cog_reader

Pure Rust COG (Cloud Optimized GeoTIFF) reader

geometry

lzw_fallback

Fallback LZW TIFF reader that streams tiles on demand.

range_reader

Range-based reader interface for COG files

raster

s3

S3 Range Reader implementation using object_store

tiff_chunked

tiff_utils

tile_cache