Calibration support for Envisat and ERS1&2 SLCs.

Author: priit111

asar_xarray/asar.py

@@ -6,6 +6,7 @@
 import pandas as pd
 import xarray as xr
 import numpy as np
+import math
 from osgeo import gdal
 from xarray.backends import AbstractDataStore
 from xarray.core.types import ReadBuffer
@@ -58,7 +59,8 @@ def open_asar_dataset(filepath: str | os.PathLike[Any] | ReadBuffer[Any] | Abstr
     metadata = get_metadata(gdal_dataset)
 
     # Duplicate, read directly from file, as gdal does not parse some necessary metadata
-    metadata["direct_parse"] = envisat_direct.parse_direct(filepath)
+
+    metadata["direct_parse"] = envisat_direct.parse_direct(filepath, metadata)
 
     # Create an xarray Dataset with pixel data and metadata attributes
     dataset: xr.Dataset = create_dataset(metadata, filepath)
@@ -80,14 +82,17 @@ def create_dataset(metadata: dict[str, Any], filepath: str) -> xr.Dataset:
     number_of_samples = metadata["line_length"]
     product_first_line_utc_time = metadata["first_line_time"]
     product_last_line_utc_time = metadata["last_line_time"]
-    print(product_first_line_utc_time)
 
     number_of_lines = metadata["records"]["main_processing_params"]["num_output_lines"]
-    azimuth_time_interval = 1 / metadata["records"]["main_processing_params"]["image_parameters"]["prf_value"][0]
+    azimuth_time_interval = metadata["line_time_interval"]
+
     range_sampling_rate = metadata["records"]["main_processing_params"]["range_samp_rate"]
     image_slant_range_time = metadata["direct_parse"]["slant_time_first"] * 1e-9
 
-    number_of_bursts = 0
+    if metadata["sph_descriptor"] == "Image Mode SLC Image":
+        product_type = "SLC"
+    else:
+        raise RuntimeError("Only Image mode SLC files(IMS) supported for now")
 
     attrs = {
         "family_name": "Envisat",
@@ -98,33 +103,29 @@ def create_dataset(metadata: dict[str, Any], filepath: str) -> xr.Dataset:
         "relative_orbit_number": metadata["rel_orbit"],
         "pass": metadata["pass"],
         "transmitter_receiver_polarisations": metadata["mds1_tx_rx_polar"],
-        "product_type": "SLC",
+        "product_type": product_type,
         "start_time": product_first_line_utc_time,
         "stop_time": product_last_line_utc_time,
-
+        "range_pixel_spacing" : metadata["range_spacing"],
+        "azimuth_pixel_spacing" : metadata["azimuth_spacing"],
         "radar_frequency": metadata["records"]["main_processing_params"]["radar_freq"] / 1e9,
         "ascending_node_time": "",
         "azimuth_pixel_spacing": metadata["records"]["main_processing_params"]["azimuth_spacing"],
-        "range_pixel_spacing": metadata["records"]["main_processing_params"]["range_samp_rate"],
         "product_first_line_utc_time": product_first_line_utc_time,
         "product_last_line_utc_time": product_last_line_utc_time,
         "azimuth_time_interval": azimuth_time_interval,
         "image_slant_range_time": image_slant_range_time,
         "range_sampling_rate": range_sampling_rate,
-        "incidence_angle_mid_swath": metadata["direct_parse"]["incidence_angle_center"],
+        "incidence_angle_mid_swath": metadata["direct_parse"]["incidence_angle_center"] * 2 * math.pi / 360 ,
         "metadata": metadata
     }
 
     azimuth_time = compute_azimuth_time(
         product_first_line_utc_time, product_last_line_utc_time, number_of_lines
     )
 
-    if number_of_bursts == 0:
-        swap_dims = {"line": "azimuth_time", "pixel": "slant_range_time"}
-    else:
-        raise NotImplementedError(
-            "Burst processing is not implemented yet."
-        )
+
+    swap_dims = {"line": "azimuth_time", "pixel": "slant_range_time"}
 
     coords: dict[str, Any] = {
         "pixel": np.arange(0, number_of_samples, dtype=int),
@@ -179,7 +180,7 @@ def get_chirp_parameters(dataset: gdal.Dataset) -> dict[str, Any]:
             new_key = key.replace('CHIRP_PARAMS_ADS_CHIRP_', '').lower()
             params['chirp'][new_key] = float(value)
 
-    params['elev_corr_factor'] = float(metadata.get('CHIRP_PARAMS_ADS_ELEV_CORR_FACTOR'))
+    #params['elev_corr_factor'] = float(metadata.get('CHIRP_PARAMS_ADS_ELEV_CORR_FACTOR'))
     params['cal_pulse_info'] = get_chirp_cal_pulse_info(metadata)
 
     return params

asar_xarray/aux/ASAR_Auxiliary_Files/ASAR Aux file list.txt

@@ -0,0 +1,45 @@
+ASAR Auxiliary Files
+
+ASA_CON_AXVIEC20030703_000000_20020301_000000_20020815_000000
+ASA_CON_AXVIEC20030909_000000_20020815_000000_20021017_130000
+ASA_CON_AXVIEC20120626_153045_20030601_000000_20050916_195733
+ASA_CON_AXVIEC20120626_153730_20021017_130000_20030601_000000
+ASA_CON_AXVIEC20120626_154436_20050916_195733_20070204_165113
+ASA_CON_AXVIEC20120626_155037_20070204_165113_20101231_000000
+ASA_CON_AXVIEC20120626_160512_20100317_120410_20141231_000000
+ASA_CON_AXVIEC20120626_163200_20100311_094400_20100317_120409
+ASA_CON_AXVIEC20120627_074358_20101027_215740_20141231_000000
+
+ASA_INS_AXVIEC20020308_112323_20020301_000000_20021231_000000
+ASA_INS_AXVIEC20020425_093155_20020413_000000_20021231_000000
+ASA_INS_AXVIEC20021018_095608_20020613_092400_20020815_131000
+ASA_INS_AXVIEC20031212_122530_20020815_131000_20021017_162400
+ASA_INS_AXVIEC20061220_105425_20030211_000000_20071231_000000
+ASA_INS_AXVIEC20070223_140724_20070226_000000_20071231_000000
+ASA_INS_AXVIEC20070227_105626_20070228_060000_20071231_000000
+ASA_INS_AXVIEC20090525_115408_20070307_060000_20090428_095959
+ASA_INS_AXVIEC20091217_114637_20090428_100000_20101231_235959
+ASA_INS_AXVIEC20101222_143805_20101022_000000_20141231_235959
+ASA_INS_AXVIEC20110124_114858_20101228_112000_20141231_235959
+ASA_INS_AXVIEC20170504_152600_20021030_100500_20030211_000000
+ASA_INS_AXVIEC20170504_152900_20021017_162400_20021030_100500
+
+ASA_XCA_AXVIEC20020308_112533_20020301_000000_20021231_000000
+ASA_XCA_AXVIEC20070130_105508_20020413_000000_20030211_000000
+ASA_XCA_AXVIEC20070130_110635_20030211_000000_20030601_000000
+ASA_XCA_AXVIEC20070130_111029_20030601_000000_20030804_000000
+ASA_XCA_AXVIEC20070130_111245_20030804_000000_20040412_000000
+ASA_XCA_AXVIEC20070130_111449_20040412_000000_20050101_000000
+ASA_XCA_AXVIEC20070215_184408_20050916_195733_20070204_165113
+ASA_XCA_AXVIEC20090311_104037_20070204_165113_20080731_235959
+ASA_XCA_AXVIEC20091217_114112_20080801_000000_20101231_235959
+ASA_XCA_AXVIEC20100315_123052_20090501_000000_20110101_000000
+ASA_XCA_AXVIEC20100608_122638_20100311_094400_20100317_120409
+ASA_XCA_AXVIEC20100608_123419_20100317_120410_20110101_000000
+ASA_XCA_AXVIEC20101111_113830_20100601_000000_20141231_000000
+ASA_XCA_AXVIEC20110526_075734_20101027_215740_20141231_000000
+ASA_XCA_AXVIEC20120126_110323_20110607_000000_20141231_000000
+ASA_XCA_AXVIEC20120607_091724_20120127_000000_20141231_000000
+ASA_XCA_AXVIEC20161028_150126_20050101_000000_20050914_080040
+
+ASA_XCH_AXVIEC20101222_143057_20020301_000000_20141231_000000