PITS Apparent Depth Profiles for Mars Global Cave Candidate Catalog (MGC3) Features

Apparent depth profiles calculated by the Pit Topography from Shadows (PITS) tool for the majority of the features in the Mars Global Cave Candidate Catalog (MGC³). PITS is a Python framework for automatically calculating apparent depth profiles for Martian and Lunar pits from just a single cropped satellite image. These images can also be single- or multi-band, such as in the case of the Mars Reconnaissance Orbiter (MRO) HiRISE camera. You can learn more about PITS by reading its journal article in RAS Techniques and Instruments, going to its GitHub repository or reading the following post.

Since not all catalogued cave candidates on Mars will be pits, PITS has so far been applied to the following MGC³ subcategories:

• Atypical Pit Craters (APCs).

With plans to extend this to:

• Lava tube skylights,
• small rimless pits,
• generic, amorphous pits,
• and polar pits.

This totals 123 apparent depth profiles in CSV format, which have been derived automatically by PITS for 88 APCs. Therefore, these profiles can be plotted as the user prefers, and/or used in combination with other data to reveal more about this particular APC on the surface of Mars.

Each depth profile's CSV file is named according to the HiRISE Reduced Data Record Version 1.1. (RDRV11) that it was calculated upon (e.g. ESP_011386_2065_RED_profile.csv for the red-band version of the HiRISE image ESP_011386_2065). Where there are multiple MGC3 APCs contained within a single image, the file names are numbered generally from the most northern to southernmost, or most westerly to easterly. ESRI shapefiles for the location of all APCs in each HiRISE image have been provided in polygon (containing the extents used to crop the larger HiRISE product) and point format in order to give context in these intances. 

As the headers suggest, the first four columns represent the shadow length (\(L\)), apparent depth (\(h\)), and the upper/lower bounds of \(\Delta h\), respectively, before they have been corrected for non-zero emission angles (\(\varepsilon\)) at the time of image acquisition. Whereas the latter four columns represent the same quantities after \(\varepsilon\)-correction. How this correction is derived and applied is explained in the PITS journal article linked above.