google-earth-engine
Is there a possibility to do "Map.addLayer" so the image is not already displayed in the output but can be loaded in via check mark in the layer dropdown?
(I would like to do the reverse of the default "Map.addLayer"….. visual go through multiple images, by default, all with Map.addLayer are displayed and I wondered if there is a better way, then manually disable each Layer in the Output by clicking away the check mark).
(Note: I know nothing about appropriate visualization of "EVI" data; my suggestions in this answer are general advice on Earth Engine programming and not specifically recommended as good visualizations.)
I know that these bands do exist…
You checked img161, where those band names do exist, but you're trying to visualize evi, which does not have those bands — it has one band, which you just computed using an expression:
var evi = img161.expression(
'2.5 * ((NIR - RED) / (NIR + 6 * RED - 7.5 * BLUE + 1))', {
'NIR': img161.select('B8'),
'RED': img161.select('B4'),
'BLUE': img161.select('B2')
});
When you compute an image by doing arithmetic on single band images (as you have provided here using .select()), the output is also single-band (and the band name is often irrelevant — here it is 'constant' because the very first input is the constant-image-value 2.5).
You have one band, but your evivisparam specifies three bands. The question, then, is: what kind of visualization do you want?
If grayscale will do, remove bands from the visualization parameters.
var evivisparam = {min: -1, max: 1};
If you want a color gradient, specify a palette in the visualization parameters.
var evivisparam = {min: -1, max: 1, palette: ['FF0000', '000000', '00FF44']};
If you want one color channel to be the EVI value and others to be the original bands, then you need to recombine the computed EVI band with the original image bands, and specify suitable visualization parameters for red, green, and blue:
var evivisparam = {
min: [-11000, -1, -11000],
max: [11000, 1, 11000],
bands: ['B4', 'evi', 'B2']
};
var img161WithEvi = img161.addBands(evi.rename('evi'));
Map.addLayer(img161WithEvi, evivisparam, 'EVI img161');
Is not a GEE error/lack of data. This dataset hasn't global coverage. From CHIRPS: Rainfall Estimates from Rain Gauge and Satellite Observations
CHIRPS Overview
Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) is a 35+ year quasi-global rainfall data set. Spanning 50°S-50°N (and all longitudes) and ranging from 1981 to near-present, CHIRPS incorporates our in-house climatology, CHPclim, 0.05° resolution satellite imagery, and in-situ station data to create gridded rainfall time series for trend analysis and seasonal drought monitoring.
Best Answer
From the documentation
I think what you want is done by parameter shown. Set it to false and the image will be added to the
Mapbut not displayed