Google Earth Engine 4: Mapping a Function over an Image Collection

Поделиться
HTML-код
  • Опубликовано: 9 янв 2025

Комментарии • 11

  • @MaisarahAhmad-bk5yk
    @MaisarahAhmad-bk5yk 5 месяцев назад

    Hi...thank you for these classes they are good understandable and helps me alot.
    I have a question: What makes you decide which Landsat8 type to use when working with it. Example you used different Landsats in Filtering... and in Mapping...

  • @carloshumbertooviedosanabr6730
    @carloshumbertooviedosanabr6730 4 года назад

    Hello,
    I need help with this problem, please:
    Error generating chart: User memory limit exceeded.
    How make large Time Series in GEE with ui.Chart.image.doySeriesByRegion for ImageCollection?
    Thanks Sam

  • @theophilusnwosu9607
    @theophilusnwosu9607 5 лет назад

    Hi, I am New to GEE, I want to come up with the average NDVI for a time series, would it require a reducer (saw it somewhere) or use of another function? how would one go about it? Can you please help?

  • @rupsasarkar1526
    @rupsasarkar1526 5 лет назад

    I have mapped NDVI over image collection and created a mask for the forest ( i.e. my region of interest). Next I want to calculate the area of the forest of each image in the image collection, can you please help?

    • @kevinzhu5855
      @kevinzhu5855 5 лет назад

      According to the tutorial developers.google.com/earth-engine/tutorial_forest_03#calculating-pixel-areas you could do
      where forestImage is your roi as an image
      // multiply forest image by image pixel area to get the area of each pixel in your image
      var forestAreaImage = forestImage.multiply(ee.Image.pixelArea());
      // use a reducer to get the sum stats
      var stats = forestAreaImage.reduceRegion({
      reducer: ee.Reducer.sum(),
      geometry: yourForest
      scale: yourScale
      maxPixels: 1e9
      });
      idk if itll work, but I just followed the tutorial to extrapolate what to do with your image
      read it for yourself and hopefully itll help

  • @kimianoroozi2112
    @kimianoroozi2112 5 лет назад

    hi,
    how can I export these outputs in order to use them in other applications such as ArcGIS?

    • @ProgramSam
      @ProgramSam  5 лет назад

      Check out the video about exporting rater and vector data: ruclips.net/video/bhl8dQkpVO4/видео.html

  • @munawarhussain3523
    @munawarhussain3523 5 лет назад

    in my case features:[ ] , can you kindly tell me problem in my below code:
    var MyCollection = L8.filterBounds(Point)
    .filterMetadata('CLOUS_COVER', 'less_than', 1);
    function calculateNDVI (image){
    var selected = image.select('B4','B5');
    var NDVI = selected.expression('(b(1)-b(0))/(b(0)+b(1))').select(['B5'],['NDVI']);
    return NDVI;

    }
    var NDVIcollection= MyCollection.map(calculateNDVI);
    print (NDVIcollection);

  • @hector_1558
    @hector_1558 4 года назад

    can anyone tell me the same NDSI
    snow part

    • @ProgramSam
      @ProgramSam  4 года назад

      NDSI seems to be very similar to NDVI, but uses different bands. namely the green and short wave infra red band. Around minute two you see how the bands are selected and inserted into the expression. If you want to do the calculation with other bands, you can change those there.