Create a multiband constant Image from a list object

Question

I get values as a list from another computation and I would like to create an ee.Image with 1 band for each value.

I wanted to do it as specified in the documentation:

var list = ee.List([1,2,3])
var image = ee.Image(list)
var buffer = geometry.buffer(1)
var values = image.reduceRegion(ee.Reducer.first(), buffer, 1)
print(values)

but I get the following error:

A mapped function's arguments cannot be used in client-side operations

If I use the getInfo() method on list it works but I would like to avoid client side operation, is there another way ?

Here is the example with the point geometry: https://code.earthengine.google.com/11a69463743086cf20709ab359d8289c

Answer 1

To instantiate a multi-band constant image using an ee.List, you'll need to use ee.Image.constant instead of ee.Image.

var list = ee.List([1,2,3]);
var image = ee.Image.constant(list); // Works!
var bad_image = ee.Image(list); // Doesn't work :(

I suspect this is unintended behavior since the ee.Image constructor works as a shortcut for creating constant images in most cases including with client-side lists, but it's an easy workaround at least.

• Pierrick Rambaud: thanks I t though constant was only accepting Array and numbers, I should have tried. It's mentioned in the documentation: developers.google.com/earth-engine/apidocs/ee-image-constant