Altimetry Search

This notebook demonstrates how to search and select satellite altimetry passes (SWOT science and cal/val phases) by date and geographic area, using Altimetry Search tool

Use Altimetry Search Binder

Follow this link to open Altimetry Search tool.

Use the top right dropdown list to select a mission (only Swot swath and Swot nadir available for now) and a period of interest. Then, with the left widget, select the area of interest (square icon). You can also use the + and - buttons to zoom in and out and wheel mouse to zoom in and out. Once you have selected the area of interest, click on the Search button to search for SWOT passes. The results are displayed in the table below and the swaths that intersect the area of interest are displayed on the map. Click on the marker to view the pass number.

You can draw multiple bounding boxes, but only the last one will be used for the search. You can also delete one or all bounding boxes by clicking on the trash icon.

Use of the Python API

Note

Required environment to run the following:

altimetry-search
pyinterp
numpy

import numpy
import pyinterp.geometry.geographic as py_geo
from altimetry.search import Mission, get_selected_passes, get_pass_passage_time, get_passes_crossing_polygon

import numpy
import pyinterp.geometry.geographic as py_geo
from altimetry.search import Mission, get_selected_passes, get_pass_passage_time, get_passes_crossing_polygon

mission = Mission.SWOT_SWATH_SCIENCE

# Search all passes starting within one cycle of a given date
selected_passes = get_selected_passes(
    mission,
    date=numpy.datetime64("2024-01-01"),
)
selected_passes

	cycle_number	pass_number	first_measurement	last_measurement
0	8	496	2023-12-14 06:49:20.010	2023-12-14 06:49:20.010
1	8	497	2023-12-14 06:49:20.010	2023-12-14 06:49:20.010
2	8	498	2023-12-14 06:49:20.010	2023-12-14 06:49:20.010
3	8	499	2023-12-14 06:49:20.010	2023-12-14 06:49:20.010
4	8	500	2023-12-14 06:49:20.010	2023-12-14 06:49:20.010
...	...	...	...	...
580	9	492	2024-01-04 03:34:26.795	2024-01-04 03:34:26.795
581	9	493	2024-01-04 03:34:26.795	2024-01-04 03:34:26.795
582	9	494	2024-01-04 03:34:26.795	2024-01-04 03:34:26.795
583	9	495	2024-01-04 03:34:26.795	2024-01-04 03:34:26.795
584	9	496	2024-01-04 03:34:26.795	2024-01-04 03:34:26.795

585 rows × 4 columns

# Get the list of passes numbers intersecting a polygon
bbox = py_geo.algorithms.from_wkt(
    'POLYGON((-6 36,-6 60,36 60,36 36,-6 36))')

passes = numpy.array(sorted(set(selected_passes['pass_number'])))

passes_list = get_passes_crossing_polygon(
    mission=mission,
    polygon=bbox,
    passes=passes
)
passes_list

array([  1,  12,  14,  27,  29,  40,  42,  55,  57,  68,  70,  83,  85,
        96,  98, 111, 113, 124, 126, 139, 141, 150, 152, 167, 169, 178,
       180, 195, 197, 206, 208, 223, 225, 234, 236, 251, 253, 262, 264,
       277, 279, 290, 292, 305, 307, 318, 320, 333, 335, 346, 348, 361,
       363, 374, 376, 389, 391, 402, 404, 417, 419, 428, 430, 432, 445,
       447, 456, 458, 473, 475, 484, 486, 501, 503, 512, 514, 529, 531,
       540, 542, 555, 557, 559, 568, 570, 583], dtype=uint16)

# Restrict passes to those crossing a given area, and get the passage time
# window for each of them

passage_time = get_pass_passage_time(
    mission,
    selected_passes,
    polygon=bbox
)
passage_time

	pass_number	first_time	last_time
0	1	0 days 00:36:45.770050944	0 days 00:44:03.526295142
1	12	0 days 09:33:17.772689177	0 days 09:40:51.148614400
2	14	0 days 11:16:42.388172748	0 days 11:23:32.610013491
3	27	0 days 22:54:10.109774617	0 days 22:58:41.440314470
4	29	1 days 00:37:13.425947417	1 days 00:44:35.561036108
...	...	...	...
81	557	19 days 21:21:21.624684364	19 days 21:28:34.992193152
82	559	19 days 23:10:47.918689254	19 days 23:11:01.684500019
83	568	20 days 06:17:52.940961433	20 days 06:25:31.325494451
84	570	20 days 08:01:09.422523059	20 days 08:08:02.780811059
85	583	20 days 19:38:37.462687052	20 days 19:41:37.166452710

86 rows × 3 columns

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