Tools to work with Cloud optimized GeogTiff (COG)
- Completely javascript based, works in the browser and nodejs
- Lazy load Tiffs images and metadata
- Supports huge 100GB+ COGs
- Uses GDAL Tiffs optimizations, generally only one or two reads per tile!
- Loads Tiffs from URL, File, Google Cloud or AWS S3
- Used in production for LINZ's Basemaps with billions of tiles fetched from COGs!
Load a COG from a URL using fetch
import { SourceHttp } from '@chunkd/source-http'; const source = new SourceHttp('https://example.com/cog.tif'); const cog = await Tiff.create(source); const img = cog.images[0]; if (img.isTiled()) throw new Error('Tiff is not tiled'); const tile = await img.getTile(2, 2); // Fetch a tile from a tiff x:2, y:2 // Tiff tags can be directly accessed too img.value(TiffTag.GdalNoData); // "-9999" // or tag metadata can be fetched img.tags.get(TiffTag.GdalNoData); /** { type: 'inline', // How the tag was read "inline" vs "lazy" id: 42113, // Tag Id (@see TiffTag) name: 'GdalNoData', // Tag Name count: 6, // Number of values value: '-9999', dataType: 2, // Char tagOffset: 194 // Bytes into the file where the tag was read. } */
npm i -g @cogeotiff/cli
Display basic information about COG
cogeotiff info webp.cog.tif
Output:
COG File Info - /home/blacha/Downloads/tif-new/bg43.webp.cog.tif
Tiff type BigTiff (v43)
Chunk size 64 KB
Bytes read 64 KB (1 Chunk)
Images
Compression image/webp
Origin 18550349.52047286,-5596413.462927464,0
Resolution 19.10925707129406,-19.10925707129415,0
BoundingBox 18550349.52047286,-5713820.738373496,19098250.139221005,-5596413.462927464
Info
Id Size Tile Size Tile Count
0 28672x6144 56x12 672
1 14336x3072 28x6 168
2 7168x1536 14x3 42
3 3584x768 7x2 14
4 1792x384 4x1 4
5 896x192 2x1 2
6 448x96 1x1 1
GDAL
COG optimized true
COG broken false
Tile order RowMajor
Tile leader uint32 - 4 Bytes
Mask interleaved false
Dump all tiles for a image (Warning if you do this for a large cog this will create millions of files.)
cogeotiff dump --image 2 --output output
This requires NodeJs >= 18 & Yarn
Use n to manage nodeJs versions
# Download the latest nodejs & yarn n latest npm install -g yarn # Install node deps yarn # Build everything into /build yarn run build # Run the unit tests yarn run test