Version 4.1 of the Land Cover Database is now available from our download portal at https://lris.scinfo.org.nz/layer/423-lcdb-v41-land-cover-database-version-41-mainland-new-zealand/  for the mainland and near shore islands, and for the Chatham Islands at https://lris.scinfo.org.nz/layer/427-lcdb-v41-land-cover-database-version-41-chatham-islands/.

In addition to the update and inclusion of all time-steps for the Chatham Islands, LCDB v4.1 is an improvement to LCDB v4.0 as a result of three processes:

• Significant contradictions in woody land covers between LCDB v4.0 and 2012 Kyoto Land Use Mapping were investigated and, where necessary, corrections made - these mainly represented indigenous/exotic and forest/scrub confusions.
• Unmapped woody vegetation patches in grassland polygons were detected by spectral methods verified with radar (ALOS PALSAR) analysis, and incorporated in a semi-automated process.
• Error-correction arising from user feedback and limited 'green field mapping' improvements were made during and following the foregoing processes.

Of course, these changes are cumulative from those made in version 4.0 released in June 2014 that, added the 2012 time-step and incorporated a variety of other improvements.

In version 4.1, over 12,500 new polygons (>1 ha) of woody vegetation in grassland were identified using a radar based semi-automated process. These new polygons cover 21,000 hectares. Along with the other improvement processes mentioned above, over 27,000 polygons are either new, have changed class or have been significantly re-mapped (> 20% of their area changed) to improve boundaries. These new or improved polygons represent nearly 646,000 hectares. A direct intersection with v4.0 produces over 56,000 polygons covering 340,000 hectares where the class is now different at one or more time-steps compared to the previous version.

Error Feedback

As always we encourage users to feedback any errors they are aware of. The online data quality feedback (DQF) facility incorporated into the download site is provided for this purpose . It enables users to report specific polygons as requiring attention by submitting a tracked report, or ticket, giving details of the problem and attaching associated evidence such as pictures, screen shots etc. While we encourage the use of the DQF facility we are happy to receive feedback in any form convenient to the user.

Usage Feedback

As any user can download the LCDB we will not always be aware of applications making use of it. We would really appreciate any feedback you are willing to give us on this, both to help us report to the Ministry of Business Innovation and Employment (our funders), but also to help chart the future for the LCDB. Even a couple of lines in an email alerting us to an application would be useful – we can always follow up if we need more detail. Alternatively, feel free to call me or Peter Newsome on 03 321 9763 or 06 353 4975 respectively, to let us know what you do with LCDB.

Associated data

Three sets of summary pivot tables have been generated from LCDB v4.1 to show change between the time steps, i.e., 1996-2001, 2001-2008, and 2008-2012. These tables contain analysis for both the national coverage and by region, including a table for the Chatham Islands. They are best accessed via the links on the LCDB v4.1 download pages shown above.

There is also a version trace layer to track non-temporal change between LCDB v4.0 and LCDB v4.1 available at https://lris.scinfo.org.nz/layer/429-lcdb-v41-version-trace-mainland-new-zealand/.  As all four time steps are present in v4.1, this version trace layer, and the earlier traces for v4.0 vs 3.3, v3.3 vs v3.0 and v3.0 vs LCDB-2, are only relevant to users who need to reconcile analysis done on an earlier version of LCDB with results from a newer version. You should only need the most recent LCDB version for new studies of real temporal change.

Future versions