Subsetting added

CHANGES.md

@@ -1,3 +1,8 @@
+## Changes in 0.2.5 (under development)
+
+* Added subsetting and reprojection in analysis mode via parameters `crs`
+  `resolution` and `bbox`.
+
 ## Changes in 0.2.4 (from 2025-11-17)
 
 * Added support for **common band names** from the [STAC EO extension](https://github.com/stac-extensions/eo?tab=readme-ov-file#common-band-names)

docs/guide.md

@@ -36,25 +36,30 @@ form. All bands and quality flags are resampled to a unified, user-provided reso
 Parameters `**kwargs`:
 
 - `resolution`: Target resolution for all spatial data variables / bands.
+- `crs`: Coordinate reference system of the output dataset. If not provided, a
+  mission-specific default CRS is used (see the respective mission sections below).
+- `bbox`: Bounding box `[west, south, east, north]` used for spatial subsetting;
+  coordinates must be in the same CRS as `crs`.
 - `interp_methods`: for upsampling / interpolating
-    spatial data variables. Can be a single interpolation method for all
-    variables or a dictionary mapping variable names or dtypes to
-    interpolation method. Supported methods include:
+  spatial data variables. Can be a single interpolation method for all
+  variables or a dictionary mapping variable names or dtypes to
+  interpolation method. Supported methods include:
 
     - `0` (nearest neighbor)
     - `1` (linear / bilinear)
     - `"nearest"`
     - `"triangular"`
     - `"bilinear"`
 
-    The default is `0` for integer arrays (e.g. Sentinel-2 L2A SCL),
-    else `1`.
+  The default is `0` for integer arrays (e.g. Sentinel-2 L2A SCL),
+  else `1`. For more information view [xcube-resampling Documentation](https://xcube-dev.github.io/xcube-resampling/guide/#spatial-resampling-algorithms).
 - `agg_methods`: Optional aggregation methods to be used for downsampling
   spatial data variables / bands. Can be a single method for all variables or 
   a dictionary mapping variable names or dtypes to methods. Supported methods include:
     `"center"`, `"count"`, `"first"`, `"last"`, `"max"`, `"mean"`, `"median"`, 
     `"mode"`, `"min"`, `"prod"`, `"std"`, `"sum"`, and `"var"`.
   Defaults to `"center"` for integer arrays (e.g. Sentinel-2 L2A SCL), else `"mean"`.
+  For more information view [xcube-resampling Documentation](https://xcube-dev.github.io/xcube-resampling/guide/#spatial-resampling-algorithms).
 - `variables`: Variables to include in the dataset. Can be a name or regex pattern 
   or iterable of the latter.
 - `product_type`: Product type name, such as `"MSIL1C"`. 
@@ -88,12 +93,22 @@ bands from multiple resolutions onto the same grid using [affine transformation
 - [Sentinel-2 Level-1C](https://stac.browser.user.eopf.eodc.eu/collections/sentinel-2-l1c)
 - [Sentinel-2 Level-2A](https://stac.browser.user.eopf.eodc.eu/collections/sentinel-2-l2a)
 
+**Supported Variables**
+
+- **Surface reflectance bands**:
+  `b01`, `b02`, `b03`, `b04`, `b05`, `b06`, `b07`, `b08`, `b8a`, `b09`, `b11`, `b12`
+- **Classification/Quality layers** (L2A only):
+  `cld`, `scl`, `snw`
+
 **Specific Sentinel-2 parameters `**kwargs`:**
 
-- `variables`: The common spectral band names specified in the [STAC EO extension](https://github.com/stac-extensions/eo?tab=readme-ov-file#common-band-names)
-  are supported for the Sentinel-2 analysis mode.
-- `resolution`: Target resolution for all spatial data variables / bands.
-  Must be one of `10`, `20`, or `60`.  
+- `variables`: Select specific spectral bands using the names listed above in
+  *Suported Variables*. Common spectral band names from the [STAC EO extension](https://github.com/stac-extensions/eo?tab=readme-ov-file#common-band-names) are also supported for Sentinel-2 analysis mode.
+- `crs`: Coordinate reference system of the output dataset.
+  If not specified, the UTM grid of the native data is used.
+- `resolution`: Target resolution for all spatial variables/bands.
+  Choose 10, 20, or 60 meters to minimize resampling and retain some of the native
+  data resolution.
 
 Examples:  
 - [Example notebook - open-sen2.ipynb](https://github.com/EOPF-Sample-Service/xarray-eopf/blob/main/examples/open-sen2.ipynb)  
@@ -128,6 +143,41 @@ for details.
 - [Sentinel-3 SLSTR Level-1 RBT](https://stac.browser.user.eopf.eodc.eu/collections/sentinel-3-slstr-l1-rbt)
 - [Sentinel-3 SLSTR Level-2 LST](https://stac.browser.user.eopf.eodc.eu/collections/sentinel-3-slstr-l2-lst)
 
+
+**Supported Variables:**
+- `sentinel-3-olci-l1-efr`:
+  `oa01_radiance`, `oa02_radiance`, `oa03_radiance`, `oa04_radiance`, `oa05_radiance`,
+  `oa06_radiance`, `oa07_radiance`, `oa08_radiance`, `oa09_radiance`, `oa10_radiance`,
+  `oa11_radiance`, `oa12_radiance`, `oa13_radiance`, `oa14_radiance`, `oa15_radiance`,
+  `oa16_radiance`, `oa17_radiance`, `oa18_radiance`, `oa19_radiance`, `oa20_radiance`,
+  `oa21_radiance`
+- `sentinel-3-olci-l2-lfr`:
+  `gifapar`, `iwv`, `otci`, `rc681`, `rc865`
+- `sentinel-3-slstr-l1-rbt`:
+  `s1_radiance_an`, `s2_radiance_an`, `s3_radiance_an`, `s4_radiance_an`,
+  `s5_radiance_an`, `s6_radiance_an`, `s1_radiance_ao`, `s2_radiance_ao`,
+  `s3_radiance_ao`, `s4_radiance_ao`, `s5_radiance_ao`, `s6_radiance_ao`,
+  `s4_radiance_bn`, `s5_radiance_bn`, `s6_radiance_bn`, `s4_radiance_bo`,
+  `s5_radiance_bo`, `s6_radiance_bo`, `f1_bt_fn`, `f1_bt_fo`, `f2_bt_in`,
+  `f2_bt_io`, `s7_bt_in`, `s8_bt_in`, `s9_bt_in`, `s7_bt_io`, `s8_bt_io`,
+  `s9_bt_io`
+- `sentinel-3-slstr-l2-lst`:
+  `lst`
+
+**Specific Sentinel-2 parameters `**kwargs`:**
+
+- `variables`: Select varaibles using the names listed above om *Supported Variables*.
+- `crs`: Coordinate reference system of the output dataset.
+  If not specified, [EPSG:4326](https://epsg.io/4326) is used.
+- `resolution`: Target resolution for all spatial variables/bands.
+  If not specified, the default is set per product:
+
+    - Sentinel-3 OLCI Level-1 EFR: 300 meter
+    - Sentinel-3 OLCI Level-1 ERR: 1200 meter
+    - Sentinel-3 OLCI Level-2 LFR: 300 meter
+    - Sentinel-3 SLSTR Level-1 RBT: 500 meter (1000 meter if selected variables come from F- or I-stripe)
+    - Sentinel-3 SLSTR Level-2 LST: 1000 meter
+
 Example:  
 - [Example notebook (open-sen3.ipynb)](https://github.com/EOPF-Sample-Service/xarray-eopf/blob/main/examples/open-sen3.ipynb)