ALTO map Methods

ALTO methods

Methods

How each data release was made: what changed, the methods, the checks and the limits. Newest release first; the map shows the current release, and each release’s page links the others. How ALTO is made gives the overview.

Overview

  • How ALTO is madeSources, crowns, record links, estimates, reviews and releases

Releases

  1. Release 6.3: Benefit value, height checks and group areas

    Makes the benefit value stormwater plus carbon (about NZ$76.7 million a year, down from about NZ$295 million) and withholds PM2.5 removal and the cooling index; checks heights and record-to-crown links; stores the height class and crown replacement time; joins Notable Group of Trees areas and Schedule 10 entries; records every source’s licence; fixes species names. Tree numbers, positions and crown outlines are those of release 6.2.

  2. Release 6.2: Reviewer-confirmed crowns and palm-type crowns

    · Current release

    Applies reviewer confirmations to 326 records and shows 16,226 crowns that release 6 left undetermined as palm-type. Tree numbers, positions and crown outlines are those of release 6.1.

  3. Release 6.1: Permanent tree numbers

    Issues 4,200,336 permanent tree numbers (3,574,821 markers on the map and 625,515 earlier LiDAR detections kept as records), publishes a table that resolves every tree ID and crown key ALTO has published, and applies the corrections ledger in full.

  4. Release 6: Growth form and smoothed crown outlines

    Estimates a growth form for each crown of the 2024 LiDAR survey, redraws every crown with a smoothed outline of the same cells and revises the benefit estimates with the growth form.

  5. Release 5.2: Linking records to crowns

    Links records that release 5.1 left without a crown to the crowns they stand on.

  6. Release 5.1: Restoring links between records and crowns

    Reconnects existing records to existing crowns. The canopy is not redrawn.

  7. Release 5: Redrawing Auckland’s canopy

    Redraws the canopy from the 2024 LiDAR survey and aerial imagery: 3,352,851 LiDAR crowns 3 m or taller across all 3,149 completed tiles of the survey.

Release 4 (18 Sep 2026) and earlier have no methods page. How Species maxima are measured: Species maxima. Every source ALTO uses, with its licence: Sources and credits.

The map tool has its own version number, shown in About. Every change to the tool and to the data files, in developer terms, is listed in the changelog.