Guides
Guides
  1. HERE Anonymizer Self-Hosted User Guide
  2. Concepts
  3. Anonymization features

Smart gapping

Split & gap

Split & gap is an anonymization method that works on real-time probes and applies an anonymization strategy across all chunks of a single journey. It is sometimes also referred to as split and gap.

The input trajectory chunk is split into a number of anonymized sub-trajectories defined by the anonymization strategy.

You can configure this anonymization method using the following parameters:

  • Sub trajectory length
  • Gap length
  • Sampling rate

The output of this anonymization method is zero (for chunks that are too small to split) or more sub-trajectories, returned to the output sink as data messages depending on the output format.

Each anonymized sub-trajectory has a new, random identifier that isn't linked to the original trajectory ID.

Junction-based gapping

The Junction-based gapping feature, powered by the Smart-gap "Short Horizon" algorithm, introduces a more advanced method for creating gaps in vehicle location traces. This approach enhances privacy while preserving valuable route data.

Unlike traditional gapping methods, Junction-based gapping leverages road infrastructure data to intelligently determine where gaps should be applied. This increases the difficulty of reverse-engineering anonymized traces, thereby improving overall data protection.

Requirements

To enable Junction-based gapping, map data containing road junctions must be provided.

This data should be supplied as a set of GeoJSON files, configured via the anonymization.junctionSources section in the configuration file.

For configuration details, refer to Junction-based gapping configuration.

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Note

When using Junction-based gapping, consider configuring a more flexible range for outputTraceDuration and gapDuration. This allows the Smart-gap algorithm greater freedom to exclude junction-related trace segments more effectively.

This feature is currently supported in Batch mode only.

Generating partitioned junction data

Customers with access to the HERE OLP platform can use the JunctionPartitionsGenerator tool to create partitioned junction data as a set of GeoJSON files.

Prerequisites

  • Java 11 or newer installed

  • A valid credentials.properties file placed at:

    ~/.here/credentials.properties

Usage example

To generate partitioned junction data for HERE tile zoom level 10 and tile IDs 369037,1476147,5904580,5904581 in output folder /tmp/junctions:

java -cp "${HERE_ANONYMIZER_DIST}/cli-tools.jar" \
  com.here.anonymization.cli.JunctionPartitionsGenerator \
  10 \
  /tmp/junctions \
  369037,1476147,5904580,5904581

The script output:

17:07:19.325 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476150.json is created with 54632 junction points
17:07:22.194 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476151.json is created with 7551 junction points
17:07:25.228 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476148.json is created with 10291 junction points
17:07:28.127 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476149.json is created with 3873 junction points
17:07:31.369 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476147.json is created with 42245 junction points
17:07:34.383 INFO  c.h.a.c.JunctionPartitionsGenerator - File /tmp/junctions/1476145.json is created with 8335 junction points
17:07:34.383 INFO  c.h.a.c.JunctionPartitionsGenerator - All the tiles are in /tmp/junctions
17:07:34.392 INFO  c.h.a.c.JunctionPartitionsGenerator - Optional 'here-tiles.geojson' file created to visualize tiles coverage: /tmp/junctions/here-tiles.geojson

Once generated, upload the /tmp/junctions/ folder to your storage solution (for example, AWS S3), and configure the location using the anonymization.junctionSources.folderUri parameter.

Updated 26 days ago