## snap_graph.GeocodingConfig


Terrain-Correction tail parameters shared by every product type.


Usage

``` python
snap_graph.GeocodingConfig()
```


Abstract: inherited by each per-product config, which supplies the graph that precedes the shared Terrain-Correction tail via [to_xml](snap_graph.CoherenceConfig.md#s1bursts.snap_graph.CoherenceConfig.to_xml).


## Parameters


`grid_spacing`  
Output pixel spacing in meters of the target CRS. Must be positive.

`dem`  
DEM used for geocoding. A string selects one of SNAP's auto-download DEMs; a path (or a string with a file suffix) is passed as an external DEM.

`dem_name`  
Name of an external DEM, written to product metadata and compared before an existing product is skipped. Required when `dem` is a path, and must not be blank; ignored for SNAP's built-in DEMs, whose `dem` value is already their name. Name each DEM differently, such as by its source and version.

`img_resampling`  
Resampling of the image during terrain correction. SNAP's cubic and sinc kernels are not supported, because they corrupt the pixels next to missing data.

`dem_resampling`  
Resampling of the DEM during terrain correction.

`align_to_standard_grid`  
Snap the output to a fixed global grid, so products from different bursts and dates share pixel boundaries and can be stacked without resampling.

`external_dem_nodata`  
No-data value of an external DEM.

`external_dem_apply_egm`  
Convert an external DEM from EGM96 geoid heights to WGS84 ellipsoidal heights, which is the reference terrain correction requires. SNAP does this automatically for its built-in ACE / Copernicus / SRTM DEMs, all of which are geoid-referenced; this flag is the equivalent for an external one and is ignored unless `dem` is a path.

Set it `True` for an orthometric DEM (heights above mean sea level, the usual case for national DEMs) and leave it `False` only when the DEM already carries ellipsoidal heights. Note this default differs from SNAP's own, which is `True`. Leave it `False` for a DEM returned by `s1bursts.prepare_dem_for_snap`, which has already been converted to ellipsoidal heights. SNAP only applies EGM96, so preprocess DEMs in other vertical datums such as EGM2008 instead of enabling this option.

`replace_zeros_with_nan`  
Convert SNAP's zero fill value to NaN, so no-data does not enter later averages as a valid low value.


## Attributes

| Name | Description |
|----|----|
| [standard_grid_origin](#standard_grid_origin) | Origin of standard grid: At pixel centers. |

------------------------------------------------------------------------


#### standard_grid_origin


Origin of standard grid: At pixel centers.


`standard_grid_origin: tuple[float, float]`


## Methods

| Name | Description |
|----|----|
| [to_mermaid()](#to_mermaid) | Mermaid `flowchart LR` diagram source for this config's graph. |
| [to_xml()](#to_xml) | Build the SNAP GPT graph XML for this config. |

------------------------------------------------------------------------


#### to_mermaid()


Mermaid `flowchart LR` diagram source for this config's graph.


Usage

``` python
to_mermaid(*, snap_version=None)
```


##### Parameters


`snap_version: tuple[int, …] | None = None`  
SNAP version the graph will run under, as for [to_xml](snap_graph.CoherenceConfig.md#s1bursts.snap_graph.CoherenceConfig.to_xml). No diagram varies with it, but a config whose options need SNAP 14 cannot build its graph without it.


------------------------------------------------------------------------


#### to_xml()


Build the SNAP GPT graph XML for this config.


Usage

``` python
to_xml(*, snap_version=None)
```


##### Parameters


`snap_version: tuple[int, …] | None = None`  
SNAP version the graph will run under, from `s1bursts.snap_client.snap_version`. The backscatter graph does not vary with it; the coherence graph writes only the options that version has (see `supports_coherence_options`). Defaults to SNAP 13 and earlier.