High resolution layer HRL, dominant leaf type report 2015

Abstract

A national coverage exercise was carried out to analyse the Forest – Dominant Leaf Type using in-situ imagery data and the HRL DLT_2015 provided for verification. The DLT 2015 HRL data layer was superimposed onto the in-situ data namely; Orthoimagery (2012), OrthoImagery 2016, the CLC layers (2012, 2018), the national biotope map database layer (updated as of 2011) as well as other in-situ data and input from local expertise.

In Malta’s case it was deemed best to apply a complete coverage methodology rather than verifying specific area samples. Copernicus defines Dominant Leaf Type as another primary status layer of the HRL Forest derived from the multi-temporal satellite image data with a 20m spatial resolution and identical in outline to the Tree cover density product providing information on the dominant leaf type: broadleaved or coniferous.

In Malta’s case it was deemed best to apply a complete coverage methodology rather than verifying specific area samples. Hence each area marked as the respective leaf type (broadleaved or coniferous) was individually verified with in-situ Orthoimagery (2012 and 2016), the CLC databases (reference years 2012 and 2018) and previous run of the same HRL for 2012. All the major errors identified are categorised as “Commission” or “Omission” error types as per guidelines provided for the verification process. A small number of errors were identified during the verification process with a total of 58 cases with the majority of them being ‘Commission’ type errors with 56 cases and only 2 cases identified as ‘Omission’ errors.