a cloud-optimized binary format for storing and retrieving 3d city models based on the cityjson standard.
flatcitybuf combines the semantic richness of cityjson with the performance benefits of flatbuffers binary serialization and spatial indexing techniques. it addresses several limitations of existing cityjson formats:
- performance: enables zero-copy access to specific city objects without parsing the entire file
- cloud optimization: supports http range requests for partial data retrieval
- spatial indexing: implements a packed r-tree for efficient spatial queries
- attribute indexing: uses binary search trees for fast attribute-based filtering
- size efficiency: reduces file sizes by 50-70% compared to text-based formats
benchmarks show flatcitybuf is 10-20× faster in data retrieval compared to cityjsonseq.
- rust toolchain (cargo, rustc)
- for wasm builds: wasm-pack
build the core library and cli:
cargo build --workspace --all-features --exclude fcb_wasmbuild the wasm module:
cargo build -p fcb_wasm --target wasm32-unknown-unknown
# or
cd wasm && wasm-pack build --target web --debug --out-dir ../../tsserialize cityjson to flatcitybuf:
cargo run -p fcb_cli ser -i path/to/input.city.jsonl -o path/to/output.fcbdeserialize flatcitybuf to cityjson:
cargo run -p fcb_cli deser -i path/to/input.fcb -o path/to/output.city.jsonlget information about a flatcitybuf file:
cargo run -p fcb_cli info -i path/to/file.fcbcargo bench -p fcb_core --bench read- fcb_core: core library for reading and writing flatcitybuf files
- fcb_cli: command-line interface for converting between cityjson and flatcitybuf
- bst: binary search tree implementation for attribute indexing
- packed_rtree: packed r-tree implementation for spatial indexing
- fcb_wasm: webassembly bindings for browser usage
this project incorporates code from flatgeobuf, copyright (c) 2018, björn harrtell, licensed under the bsd 2-clause license.
the flatbuffers schema for citybuf feature format is originally authored by tu delft 3d geoinformation group, ravi peters (3dgi), balazs dukai (3dgi).