Raster Tiling
Definition
Raster tiling divides large rasters into manageable chunks for storage, processing, and web delivery. Internal tiling in formats like GeoTIFF improves read times; external tiling (XYZ/WMTS) serves map tiles as images or vector tiles. Tile size, pyramid levels, and indexing schemes (quadtree, TMS) determine performance and cache efficiency. For analysis, chunking strategies align with compute frameworks to keep data in memory. Edge artifacts and resampling at tile boundaries require careful handling. Metadata must record tiling schema and overviews. Tiling enables parallelism and responsive visualization of massive imagery collections.
Application
Imagery providers publish global mosaics; agencies serve elevation tiles; dashboards load tiles progressively; scientists process tiles on clusters for time-series analysis.
FAQ
What tile size works best?
Common internal tiles are 256–1024 pixels; choose based on storage and access patterns. For web maps, 256/512 pixel tiles are standard.
How to avoid seams between tiles?
Use overlap margins for analysis tiles and consistent resampling; for web, ensure consistent color balancing and seamlines.
Do vector tiles replace raster tiles?
Not for imagery; vector tiles complement them for features and labels with client-side styling.
How to index tiles?
XYZ schemes with z/x/y indices are ubiquitous; cloud catalogs add STAC metadata for discovery and access.