What changes in vegetation cover over time are evident at Wairio?
To what extent is the accuracy of the image classification process improved with the addition of ancillary data?
This project investigates the use of image classification techniques to create detailed maps of wetland areas based on aerial photographs.
The project uses an emerging set of analysis methods called ‘object-based image analysis’ to investigate the applications of remote identification techniques calibrated to detect selected native and invasive species.
An additional objective is to compare and contrast the improvements that including ancillary data into the classification process, such as 3D digital surface models (DSMs) or near infrared imagery, may have over classifications based solely on true-colour images.
The processes being evaluated by this project may allow teams with limited budgets or time to quickly and accurately convert imagery into maps with much greater levels of details, which will improve their ability to detect and track specific plant species.
This is especially useful in the case of wetlands undergoing restoration as they often exhibit significant changes over time, and the target species would normally be challenging to differentiate from one another in an aerial photograph.
Though the study is ongoing, with flights every three months, the initial results would appear to confirm that a ‘true-colour only’ classification would perform poorly compared with ancillary data. The improving effects of including infrared imagery will be tested once that has been gathered.
The classified images contain between 18 and 20 distinct classes.
The Wairio wetland was drained and converted into farmland in the 1960s.
Since 2005, it has been undergoing a managed restoration programme to return it to something approaching its natural state.
Several plantations of native plants have been established, and a weed eradication programme to control invasive species such as Bidens frondosa is in progress. This project can assist this effort by tracking the distribution of natives and weeds.
Object-based image analysis works on the principle that different types of surface cover have unique properties, such as colour, texture or shape.
For instance, weed species might be distinguished from grass as the weeds may be a different shade of green to the surrounding grass, or present a unique textural pattern owing to differently shaped leaves.
The sensors being used in this project are the DJI Phantom 4 Pro Camera, to collect true colour imagery, and a Micasense RedEdge-M, a multispectral sensor for collecting near infrared imagery. The software is ArcGIS Pro 21, ENVI 5.4 and PrecisionMapper 3.32
Thanks to the Nikau Foundation, Wairio wetland has again been granted a generous amount toward development for the wetland. The Richard and Doreen Evans Charitable Trust provided $4000 in the 2015 Nikau Foundation funding round.
Conditions placed on the grant:
Should any of you wish to know more go to the Foundation’s web site, www.nikaufoundation.org.nz.
The Nikau Foundation has appointed a new General Manager who brings a wealth of experience from the community and voluntary sector. Louise Parkin has had 25 years working with charitable and philanthropic organisations both in New Zealand and internationally.
Ms Parkin had been at Nikau Foundation as their Philanthropy Advisor for six months before taking up the role of General Manager in January this year.
In her spare time, she teaches the Japanese martial art of aikido to adults and children. Her personal philanthropy is for the benefit of the environment and international aid.
The Nikau Foundation is part of a world-wide network of community foundations set up to benefit a specific geographic area, in this case the Wellington region. The Foundation manages 22 endowment funds that benefit the arts, education, social and youth projects, the environment and beyond. It does this through the generosity of local donors. The funds it manages grew 100 percent in the last year.
The presentation of DUNZ’s certificate “in recognition and appreciation of support to NZ’s waterfowl and wetland habitat” to Ian Gunn from Greater Wellington Regional Council (GWRC) – Manager of GWRC’s Wairarapa Moana Project and a great supporter of the Wairio Wetland Restoration Project.
Ian was critical in securing a “step change” in funding for the project. The presentation was made at the end of the meeting along with the small gift of a bottle of wine. DUNZ members may recall Ian joining us at our 2014 AGM in Martinborough.
The recent meeting was held at Fish & Game’s Kilmore Lodge, adjacent to the Wetland where the group planning the 2016 work programme was underway.
Funding currently tots up to around $30,000. Of this, about $20,000 is already funded by contributions from our supporters.
June 21 work started at 9am for the organisers, supported by some strong lads from Taratahi Agricultural Training College and farm workers from a local sheep and beef station Palliser Ridge. Those strong farming trainees dug holes in pre-sprayed spots in rough, fescue infested terrain.
Just after 10am we also had about 20 school children from Martinborough and Kahutara primary schools arrive to “assist” in planting flaxes in the holes prepared by the aforementioned lads and workers. In all, around 65 folk helped with the planting and by 12 noon, 750 plants (about half of them kahikatea) were in the ground at the noreastern corner of the Wetland.
Greater Wellington Regional Council provided educational support and the school children, in addition to planting, were treated to a field class identifying plants common to the Wetland. That and the hot sausages for lunch (again provided by GWRC) made a great day for the children who said they would be back next year to see how “their” plants were growing.