The NZ Imagery Survey Index dataset provides an index to all orthophoto index tiles found on the LINZ Data Service. Each record in the dataset provides both a geometry of the maximum extent of the orthophoto index, as well as all attributes found in each index tile. This dataset therefore provides information to assess orthophoto coverage and metadata across the entire country.
Please refer to the [NZ Aerial Surveys Data Dictionary](https://nz-imagery-surveys.readthedocs.io/en/latest/introduction.html) for detailed metadata and information about this dataset.
The imagery data referenced by this dataset is available on the [LINZ Data Service](https://data.linz.govt.nz/data/category/aerial-photos/).
The NZ Imagery Survey Index dataset is an aggregation of all the index tiles layers on the LDS. The inner boundaries of each index tiles layer have been dissolved.
The dissolved layer is clipped by the corresponding imagery to get the actual edge of the survey extent. However, for some imagery there are white pixels (RGB 0, 0, 0) along the edge, and since 'no data' is also set to (RGB 0, 0, 0), there is no way to differentiate white pixels from 'no data' pixels. In these situations manual editing is involved in clipping and the resulting edge is approximate.
The attribute tables of the index tiles layers are standardised and imported into the NZ Imagery Survey Index dataset.