Mercator Indexer

Tool to generate indices for the Mercator, a spatial index.

Mercator: Spatial Index

Mercator is a spatial volumetric index for the Human Brain Project. It is a component of the Knowledge Graph service, which provides the spatial anchoring for the metadata registered as well as processes the volumetric queries.

It is build on top of the Iron Sea database toolkit.

Iron Sea: Database Toolkit

Iron Sea provides a set of database engine bricks, which can be combined and applied on arbitrary data structures.

Unlike a traditional database, it does not assume a specific physical structure for the tables nor the records, but relies on the developper to provide a set of extractor functions which are used by the specific indices provided.

This enables the index implementations to be agnostic from the underlying data structure, and re-used.

Requirements

Software

• Rust: https://www.rust-lang.org

Checkout the dependencies in the parent folder:

• mercator_db – https://github.com/epfl-dias/mercator_db
• ironsea_index – https://github.com/epfl-dias/ironsea_index
• ironsea_index_hashmap – https://github.com/epfl-dias/ironsea_index_hashmap
• ironsea_index_sfc_dbc – https://github.com/epfl-dias/ironsea_index_sfc_dbc

Quick start

For 3 datasets, setA, setB, setC, the following files are expected to be in the current folder:

• setA:
  • setA.objects.json
  • setA.spaces.json
• setB:
  • setB.objects.json
  • setB.spaces.json
• setC:
  • setC.objects.json
  • setC.spaces.json

Run (and build if necessary) the indexer:

cargo run --release -- -f json setA setB setC

This will produce the following files:

• setA
  • setA.objects.bin
  • setA.spaces.bin
  • setA.index
• setB
  • setB.objects.bin
  • setB.spaces.bin
  • setB.index
• setC
  • setC.objects.bin
  • setC.spaces.bin
  • setC.index

By default, each dataset will have a version set to the empty string, if you want to specify the dataset version you can like this:

cargo run --release -- -f json setA:v0.1 setB setC:MyAwesomeVersion

With the above, setA will have its version set to v0.1, setB to the empty string and setC to MyAwesomeVersion.

For more options, please refer to the online help:

cargo run --release -- --help

Installation

To install the software on the system, after checking out the dependencies you can use:

cargo install --path .

Then in any folder you can then use:

mercator_indexer -f json setA:v0.1 setB setC:MyAwesomeVersion

Acknowledgements

This open source software code was developed in part or in whole in the Human Brain Project, funded from the European Union’s Horizon 2020 Framework Programme for Research and Innovation under the Specific Grant Agreement No. 785907 (Human Brain Project SGA2).