## burst.Burst


Represents a single Sentinel-1 burst.


Usage

``` python
burst.Burst(
    burst_id,
    sub_swath,
    polarization,
    date,
    abs_burst_id=None,
    cdse_id=None,
    parent_product_name=None,
    _rel_orbit_number=None,
    _pass_direction=None,
    _geometry=None
)
```


A burst is a segment of SAR data acquisition characterized by its spatial location, temporal acquisition time, and imaging parameters.

Two bursts are considered equal when their [burst_id](burst.BurstPair.md#s1bursts.burst.BurstPair.burst_id), [sub_swath](burst.BurstPair.md#s1bursts.burst.BurstPair.sub_swath), [polarization](burst.BurstPair.md#s1bursts.burst.BurstPair.polarization), and calendar day (`date` normalized to midnight) match, so a burst from a CDSE search compares equal to the same acquisition reconstructed from an SLC filename (which carries only the day). A given footprint is re-acquired at most once per repeat cycle, so the day is a unique key.


## Parameter Attributes


`burst_id: int`  

`sub_swath: SubSwath`  

`polarization: Polarization`  

`date: Timestamp`  

`abs_burst_id: int | None = None`  

`cdse_id: str | None = None`  

`parent_product_name: str | None = None`  

`_rel_orbit_number: int | None = None`  

`_pass_direction: PassDirection | None = None`  

`_geometry: Polygon | MultiPolygon | None = None`  


## Attributes

| Name | Description |
|----|----|
| [pass_direction](#pass_direction) | Pass direction, propagated from CDSE or looked up from the burst map. |
| [utm_zone](#utm_zone) | The WGS 84 / UTM zone that holds the burst's footprint, the zone `crs="auto"` uses. |

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


#### pass_direction


Pass direction, propagated from CDSE or looked up from the burst map.


`pass_direction: PassDirection`


##### Raises


`BurstMapUnavailableError`  
If the value was not propagated and the burst map has not been downloaded (see [s1bursts.burstmap.download_burst_map](burstmap.download_burst_map.md#s1bursts.burstmap.download_burst_map)).

`BurstNotInMapError`  
If the burst is not found in the burst map.


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


#### utm_zone


The WGS 84 / UTM zone that holds the burst's footprint, the zone `crs="auto"` uses.


`utm_zone: CRS`


The zone is the one containing the center of the footprint, by the zone boundaries of `freezebase.mgrs.UTMZones`, the ones the MGRS grid uses, Norway and Svalbard exceptions included. A center on a border between two zones takes the eastern one, and one on the equator the northern hemisphere. The zone depends only on the burst ID and sub-swath, so a time series of one burst stays in one zone. Products meant for a composite take the target cell's zone instead, which need not be the zone of every burst.

A burst found on disk with `FileManager.find(Burst)` takes its footprint, and so its zone, from the burst-ID map, since file names record its pass direction but not its footprint.


##### Raises


`NoUTMZoneError`  
If the center lies outside the UTM zones, north of 84 degrees or south of 80 degrees. It is a `ValueError`.

`BurstMapUnavailableError`  
If the footprint was not propagated and the burst map has not been downloaded (see [s1bursts.burstmap.download_burst_map](burstmap.download_burst_map.md#s1bursts.burstmap.download_burst_map)).

`BurstNotInMapError`  
If the burst is not found in the burst map.


## Methods

| Name | Description |
|----|----|
| [__eq__()](#__eq__) | Compare identity fields with the acquisition date normalized to the day. |
| [__repr__()](#__repr__) | Return string representation of the Burst. |
| [from_dict()](#from_dict) | Instantiate from a mapping, silently dropping unknown and non-init fields. |

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


#### \_\_eq\_\_()


Compare identity fields with the acquisition date normalized to the day.


Usage

``` python
__eq__(other)
```


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


#### \_\_repr\_\_()


Return string representation of the Burst.


Usage

``` python
__repr__()
```


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


#### from_dict()


Instantiate from a mapping, silently dropping unknown and non-init fields.


Usage

``` python
from_dict(data)
```


Public footprint keys ([rel_orbit_number](burst.BurstPair.md#s1bursts.burst.BurstPair.rel_orbit_number), [pass_direction](burst.Burst.md#s1bursts.burst.Burst.pass_direction), [geometry](burst.BurstPair.md#s1bursts.burst.BurstPair.geometry)) are mapped onto the private override fields, so a burst reconstructed from a parsed SLC filename keeps its relative orbit number and pass direction instead of re-deriving them from the LUT.


##### Parameters


`data: dict[str, Any]`  
Mapping of field names to values. Extra keys and `init=False` fields are filtered before construction.


##### Returns


`Self`  
A new [Burst](burst.Burst.md#s1bursts.burst.Burst) instance.