PyReX

A recursion based crossover detection algorithm in Python for along-track geophysical measurements.

Refer to the paper for a detailed description of the algorithm used and a basic workflow of implementation of the codes.

Steps to run a calculation:

• Place the required files in the working directory, i.e.
  • script to run : detection.py, correction.py and/or stacking.py. These need not be edited by the user
  • cross_over_module.py file which contains necessary functions used by other scripts and need not be edited by user
  • config_cross.py file, to be edited by user to set up the calculation.
  • Necessary data files to work with (in ASCII formats).
• Edit config_cross.py by adding your own section with a unique calc_id or modify existing ones as per your needs.
• Run the calculation using the command $ python script.py calc_id

You can get these from the codes directory

Each calculation/run has an associated calc_id. The settings/configuration of any calculation (by any of the script) has to be done by the user inside config_cross.py file. This file can have one or multiple sections, each with a different calc_id with corresponding configuration for that particular calculation.

Please see the example/reference config_cross.py in the codes folder for details and explanations of each option

Feel free to raise any issue, and we will try to address them as much as we can. Info on any minor updates or bug fixes will be informed here.

How to cite

Please cite us as follows if you have used PyReX in your studies.

Vikram, K. V. N. G., Krishna, D. V. P., & Sreejith, K. M. (2025). PyReX: A recursion based crossover detection algorithm in Python for along-track geophysical measurements. Earth and Space Science, 12, e2024EA003932. https://doi.org/10.1029/2024EA003932

If you want to replicate the entire study of the paper, please contact us, and we will be happy to share the full satellite altimetry data we used (~6 GB).

Requirements

• numpy
• pandas
• numba
• scipy

These probably are already present in a base anaconda installation.

Running the test data

Two datasets (Group A and Group B) used in the paper for testing crossover detection between the tracks of ship borne free-air gravity measurements from NGDC is placed in the input_data/group_a and input_data/group_b folders. The example config_cross.py in codes folder is preconfigured with two calc_ids namely pyrex_group_a_detect and pyrex_group_b_detect for crossover detection of corresponding datasets.

• Go to codes folder

$ cd codes

• Run the detection for Group A with its corresponding calc_id

$ python detection.py pyrex_group_a_detect

• Similarly, run the detection for Group B with its corresponding calc_id

$ python detection.py pyrex_group_b_detect

• Extracted crossovers are present in output_detection_files folder and named corresponding to their calc_id.