Merges two image collections into one. The result has all the images that were in either collection.

<br />

| Usage | Returns |
|---|---|
| `ImageCollection.merge(collection2)` | ImageCollection |

| Argument | Type | Details |
|---|---|---|
| this: `collection1` | ImageCollection | The first collection to merge. |
| `collection2` | ImageCollection | The second collection to merge. |

## Examples

### Code Editor (JavaScript)

```javascript
// Sentinel-2 surface reflectance image collection.
var ic = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED');

// Filter the images to those that intersect Mount Shasta for 3 months
// in 2019 and 2021 (two image collections).
var geom = ee.Geometry.Point(-122.196, 41.411);
var ic2018 = ic.filterBounds(geom).filterDate('2019-07-01', '2019-10-01');
print('2018 image collection', ic2018);
var ic2021 = ic.filterBounds(geom).filterDate('2021-07-01', '2021-10-01');
print('2021 image collection', ic2021);

// Merge the two image collections.
var icMerged = ic2018.merge(ic2021);
print('Merged image collection', icMerged);
```
Python setup

See the [Python Environment](https://developers.google.com/earth-engine/guides/python_install) page for information on the Python API and using
`geemap` for interactive development.

```python
import ee
import geemap.core as geemap
```

### Colab (Python)

```python
# Sentinel-2 surface reflectance image collection.
ic = ee.ImageCollection('COPERNICUS/S2_SR_HARMONIZED')

# Filter the images to those that intersect Mount Shasta for 3 months
# in 2019 and 2021 (two image collections).
geom = ee.Geometry.Point(-122.196, 41.411)
ic2018 = ic.filterBounds(geom).filterDate('2019-07-01', '2019-10-01')
display('2018 image collection:', ic2018)
ic2021 = ic.filterBounds(geom).filterDate('2021-07-01', '2021-10-01')
display('2021 image collection:', ic2021)

# Merge the two image collections.
ic_merged = ic2018.merge(ic2021)
display('Merged image collection:', ic_merged)
```