Questions tagged [reducers]

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Exporting district level precipitation data for series of months using Google Earth Engine Python API

I am trying to export precipitation data for a range of months at the district level of Somalia using GEE's phython api. I'm using the following code #import Somalia district shape file and convert to ...
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1answer
19 views

Scene boundary issue when reducing sentinel 1 in natural values vs dB

I have written a function that smooths sentinel 1 images by reducing across clusters created from a sentinel 2 median image, and then reduces the sentinel 1 collection to the p5 value. When I run the ...
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1answer
33 views

How to find top 10 greatest values in a GEE image collection?

I'm trying to categorize temperature extremes for a region. Using the Hycom GEE dataset, I know that using a Reducer I can find the maximum value for each pixel across the image collection (see code ...
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1answer
47 views

Count pixels inside a polygon with Google Earth Engine

i'm pretty new on GEE, so i hope someone can help me with this. As the title say, i'm looking for a way to calculate how many pixels i have inside a polygon. I tried to do it with reduceRegion and ee....
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1answer
26 views

Reduction over an image collection Google Earth Engine

I am using CHIRPS data set (daily precipitation) to derive mean, median, min and max precipitation within a certain time frame. Then, I want to extract the values at specific locations included in a ...
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1answer
46 views

Google Earth Engine: get data ready for ML export

I need to export data from GEE to get processed in MATLAB. I want to export CSV files of a region, aggregating meteo data ( CAMS, ERA5, MODIS AOT) with sentinel-2 images. These images have already ...
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35 views

Why does means not appear in the Feature Collections after applying a ee.Reducer.mean() through the image.reduceRegions

I am trying to aggregate the MODIS ET data into 1km by 1km grid squares. I have tried applying the ee.Reducer.means through the image.reduceRegions to get the mean value of MODIS-ET pixels within the ...
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46 views

Retrieve projection inside .map() GEE

When using a reducing function such as .reduceRegion(), a provided projection is necessary. This projection has to be provided as CRS String, and crsTransform List. Both are optainable with : var ...
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1answer
40 views

How to calculate the area of classified pixels in Google Earth Engine?

I'm using the Python API of GEE in a Jupyter notebook. I'd like to perform a surface evaluation of classified pixels. I have a ee_map with one band called gfc that have values in [1,2 ... 19, 30, 40, ...
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1answer
26 views

Transform an ecozone raster to vector

I want to transform a ee.Iamge that descripbe the ecozone of a specific country to a vector. I try to reproduce this example but I cannot get anything else than black vector... //load the country ...
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1answer
65 views

Extracting NDVI for Landcover Classes in Google Earth Engine

I am working on a project where I have created a supervised classification of an image which contains four land cover classes. I have reduced the classification to a frequency histogram that displays ...
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21 views

Google Earth Engine: Different calculations per region in feature collection

I have a mean SST value, which I have reduced per pergion. var sstCollection = ee.ImageCollection('NASA/OCEANDATA/MODIS-Aqua/L3SMI').select('sst') .filterDate(startDate, endDate) .filterBounds(EEZ) ....
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24 views

Google Earth Engine: Sum property values for region

I have run the code below, to find regions where data is available from my image collection, which This produces a feature collection per region and per variable (in this case SST and Salinity). // ...
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1answer
88 views

Exporting table of daily temperature (ERROR: Internal Error)

I am trying to download a table of daily temperature for the year of 2001 and all Brazilian municipalities in Google Earth Engine Code (GEE). After mapping a Reduce Regions function and flatten to ...
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1answer
45 views

How to read minimum and maximum pixel values of an image in earth engine?

I want to read the minimum and maximum rainfall value for my study region. While using the reducer function I can read the mean value, however, for min and max value it is showing null. I wish to ...
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1answer
88 views

ReduceRegions not writting to feature properties in GEE

I am trying to apply reduceRegions to extract average precipitation from the TerraClimate dataset (developers.google.com/earth-engine/datasets/catalog/IDAHO_EPSCOR_TERRACLIMATE) within each polygon of ...
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1answer
84 views

Google earth engine: count number of null values per region

Following a previous post I now have some code which sets null values in an image collection to zero. I have used this code on several variables, however, I'd like to know which variables have null ...
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120 views

Difference between reduce(ee.Reducer.mean()) and mean() for ImageCollection in GEE

I am working with S5P data for NO2. I have an image collection and want to obtain the mean NO2 for specified filters. The following code is from the documentation. var collection = ee.ImageCollection('...
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1answer
63 views

FeatureCollection (Error) Image.reduceRegions: Group input must come after weighted inputs

I was trying to find the area of each block by category in the band. There is one band and it has 18 categories. The feature collection is a collection of blocks described uniquely by code_2011. var ...
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75 views

Google Earth Engine: Converting raster to vector in the same resolution as the original image

I am using Google Earth Engine to reduce a raster region to polygon vectors. What I want to achieve is: Obtain a set of polygons each of which matches the grid of measurement in the raster dataset. ...
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1answer
36 views

Cannot get canopy height from dataset

I just can't work out why this reducer does not work and give me the average canopy height. The reducer output is null even though there are pixels in the area. var fromList = ee.FeatureCollection(&...
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2answers
34 views

Google Earth Engine: Reduce every image in a collection

I want to reduce every single image in a collection, but I have not been able to make it. The process is really easy and works with a single image, but I need to do the same for every image in the ...
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13 views

Filtering an image by regional mask

How could I filter an image by an user defined mask on a user defined area? Here an example: # select area crs = 'SR-ORG:6974' scale = 926.625433056 area_extent = (294666.8877, 5639442.3861, 314126....
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52 views

Google Earth Engine - Dynamic Visualization Parameters

I made a script that calculates the maximum NDVI values of the last 100 days of an area. Therefore, depending on WHEN you run it, the resulting image. Is there any straight straightforward method to ...
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1answer
37 views

Export ReduceRegion fixedHistogram toDrive

I'm trying to export a fixed histogram from reduceRegion as a .csv file. I'm sure im missing the obvious here, but can't find a reasonable example that does this straightforward. I can do it as a ...
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1answer
77 views

Earth Engine: combining reducers does not give same output as running reducers separately?

I am trying to combine reducers, which according to my understanding, is running parallel yet independent reducers when using sharedInputs: true (see doc). But actually, I notice that with combine(), ...
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1answer
76 views

Count number of pixel for each polygon and have the data in one featurecollection [closed]

I have raster with NDVI values. I have calculate for each plot the number of pixels in different values (no. of poixels lower than 0.2, higher than 0.2 and lower than 0.4 ect....) based on masks I ...
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2answers
67 views

earthEngine: count number of fully covered pixels within a region

I would like to count the number of pixels that are fully covered by a given region/geometry. How can I do that? Using standard reducer, I can get: ee.Reducer.count() will just count the number of ...
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1answer
231 views

Multiple reducers Google Earth Engine

How can we apply more than 2 reducers to an Image? The following link shows for 2 reducers https://developers.google.com/earth-engine/reducers_intro But the following won't work: // Load a Landsat ...