Is there a way to eliminate isolated pixels just like we can do with the classification sieve of the QGIS SCP plugin?
I've done a classification of an image that contains many isolated pixels which I want to remove.
Google Earth Engine – How to Eliminate Isolated Pixels in Classified Images
google-earth-enginegoogle-earth-engine-javascript-apiland-classification
Related Solutions
My quick solution would be for one class (e.g. water):
- mask water pixels from classified image
- add Landsat DN band values
- create histogram from image
var water = upsampled.eq(0)
water = water.selfMask()
Map.addLayer(water, {}, "Water")
water = water.addBands(landsatComposite).select('B[1-4]')`
// Pre-define some customization options.
var options = {
title: 'Water - Landsat 7 DN histogram, bands 1-4',
fontSize: 20,
hAxis: {title: 'DN'},
vAxis: {title: 'count of DN'},
series: {
0: {color: 'Blue'},
1: {color: 'Green'},
2: {color: 'Red'},
3: {color: 'Magenta'}}};
// Make the histogram, set the options.
var histogram = ui.Chart.image.histogram(water, geometry, 300)
.setSeriesNames(['Blue', 'Green', 'Red', 'NIR'])
.setOptions(options);
print(histogram)
Link to whole script: https://code.earthengine.google.com/a4b56b96f8e05fba7a6b95649acaf8cd
The error “Remote request too large …” is an unfortunate limitation — unfortunate in that it really shouldn't exist, and it's also not worded very well.
What it actually means is that you're somehow trying to compute an image that's too big (number of pixels times number of bytes needed to store each pixel). Most likely, this is due to your reprojection and reduceResolution somehow requiring computing many more pixels intermediately than the reduceRegion asked for per tile of the reduction.
Ideally, Earth Engine would automatically try computing the reduction in smaller tiles. But for now, you can specify the tileScale parameter in reductions — try tileScale: 8.
As of October 24, 2019, this error message has been changed, hopefully for the better. It now reads, for example from the above script:
Output of image computation is too large (3200.0 MiB > 80.0 MiB).
If this is a reduction, try specifying a larger 'tileScale' parameter.
Best Answer
Just use a focal operator or reduceNeighborhood with a mode reducer.
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