RETIRED Water Observations from Space Statistics 25m 2.1.5

Full description

This record was retired 29/03/2022 with approval from S.Oliver as it has been superseded by eCat 146091 Geoscience Australia Landsat Water Observation Statistics Collection 3

WOfS-STATS (WO_STATS_2.1.5) is a set of statistical summaries of the water observations contained in WOfS (WO_2.1.5). The layers available are: the count of clear observations;the count of wet observations;the percentage of wet observations over time.

This product is Water Observations from Space - Statistics (WO-STATS), a set of statistical summaries of the WOfS product that combines the many years of WOfS observations into summary products that help the understanding of surface water across Australia.

WO-STATS consists of the following datasets:


    Clear Count: how many times an area could be clearly seen (ie. not affected by clouds, shadows or other satellite observation problems),
    Wet Count: how many times water was detected inobservations that were clear,
    Water Summary: what percentage of clear observations were detected as wet (ie. the ration of wet to clear as a percentage)


As no confidence filtering is applied to this product, it is affected by noise where misclassifications have occurred in the WOfS water classifications, and hence can be difficult to interpret on its own. The confidence layer and filtered summary are contained in the WO-Fil-STATS product, which provide a noise-reduced view of the water summary.

WO-STATS is available in multiple forms, depending on the length of time over which the statistics are calculated. At present the following are available:


    WO-STATS: statistics calculated from the full depth of time series (1986 to present)
    WO-STATS-ANNUAL: statistics calculated from each calendar year (1986 to present)
    WO-STATS-NOV-MAR: statistics calculated yearly from November to March (1986 to present)
    WO-STATS-APR-OCT: statistics calculated yearly from April to October (1986 to present)

Lineage

Maintenance and Update Frequency: asNeeded

Statement: The WOfS productis a key component of the National Flood Risk Information Portal (NFRIP), developed by GA. The objective of Water Observations from Space is to analyse GA's historic archive of satellite imagery to derive water observations, to help understand where flooding may have occurred in the past. The collection of many hundred thousand WOFLs that make up WOfS are too cumbersome to display easily. WO_STATS provides the mechanism to present and deliver WOfS in a moreeasily digestible form, and provides understanding of water in the landscape. WO-STATS is created from the WOfS water classification (WO_25_2.1.5).Every pixel location in WO_25_2.1.5is analysed statistically to derive the count of clear observations, the count of clear-wet observations and then calculate the percentage of clear observations that were also wet. This provides a 'normalised'water frequency product for all of Australia. basic_htmlThe WOfS product is a key component of the National Flood Risk Information Portal (NFRIP), developed by GA. The objective of Water Observations from Space is to analyse GA's historic archive of satellite imagery to derive water observations, to help understand where flooding may have occurred in the past. The collection of many hundred thousand WOFLs that make up WOfS are too cumbersome to display easily. WO_STATS provides the mechanism to present and deliver WOfS in a more easily digestible form, and provides understanding of water in the landscape. WO-STATS is created from the WOfS water classification (WO_25_2.1.5). Every pixel location in WO_25_2.1.5 is analysed statistically to derive the count of clear observations, the count of clear-wet observations and then calculate the percentage of clear observations that were also wet. This provides a 'normalised' water frequency product for all of Australia.