I am using Monthly History data of the Global Surface Water dataset (Asset id: JRC/GSW1_0/MonthlyHistory).

I have filtered the images using .filterdate and .filterbounds for my region of interest (ROI) and time period. Images are classified into water, no water and no data classes.

Now I am trying to calculate the area under each class in my ROI.

How can I do that?


As per this resource (https://global-surface-water.appspot.com/download);

'(The Global Surface Water Explorer) is intended as a data viewer and does not provide any analytical features - if you would like to do your own analysis on the data then access the data using Data Download or Google Earth Engine.'

It seems as though you may already be using GEE based on the commands you referenced ( .filterdate & .filterbounds), if so, it looks as if this tool (https://developers.google.com/earth-engine/reducers_reduce_region) is able to provide geometric summaries of pixel coverage for GEE layers. Otherwise, if you download the data, area summaries of classified raster data is a fairly simple process for most desktop GIS (for example, answers to this question cover how it can be achieved using QGIS: How to calculate raster area or number of cells for multiple classes in a raster?)

  • HI thanks for responding. The data I am using is an image collection (water history) which collection of 380 images with just one band containing values 0,1,2 for no data, no water and water. this data is not available for download and to use in ArcGIS unfortunately. I am trying to figure out how can I compute number of pixels with different values in all the 380 images but for defined spatial boundary. Hope this makes sense. Can you help please? – Bhawana Gupta Oct 3 '18 at 16:48
  • What software/application are you using to view the data? – RobinHorner Oct 3 '18 at 21:17

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