DOI: 10.15131/shef.data.23741973.v1
title: <strong>HiRISE digital terrain model (1 m/pixel) and orthorectified image (25 cm/pixel) of a viscous flow feature incised by a gully in Nereidum Montes, Mars.</strong>

description: <strong>High Resolution Imaging Science Experiment (HiRISE) digital terrain model (DTM) and orthorectified image of a viscous flow feature incised by a gully in Nereidum Montes, Mars.</strong> <br> These data products were produced by Joel Davis at the Natural History Museum, London, and re-projected by Frances Butcher at the University of Sheffield for the purposes of the study presented in: <br> <em>Butcher, F.E.G., Arnold, N.S., Conway, S.J., Berman, D.C., Davis, J.M., and Balme, M.R. 2023, The Internal Structure of a Debris-Covered Glacier on Mars Revealed by Gully Incision, Icarus, </em><em>https://doi.org/10.1016/j.icarus.2023.115717</em><em>.</em> <br> Please read the following information carefully. <strong>Data Sets </strong> The following files are present in .tif format. These are geotiffs and have geospatial metadata: - 1 m/pixel DTM: ‘NWArgyre_1_AATE_1m_Sinusoidal.tif’ - 1 m/pixel FOM (Figure of Merit - see Readme.txt): ‘FOM_NWArgyre_1_AATE_1m_Sinusoidal.tif’ - 25 cm/pixel orthoimage: ‘ESP_051036_1370_25o_Sinusoidal.tif’ - Readme.txt:Contains further information, including an explanation of the values in the Figure of Merit <br> The DTM was generated using BAE Systems SOCET SET software, with the following HiRISE images as input: -ESP_051036_1370: https://www.uahirise.org/ESP_051036_1370 -ESP_015947_1370: https://www.uahirise.org/ESP_015947_1370 <br> The orthoimage was generated by orthorectifying HiRISE image ESP_051036_1370 using the DTM. <br> The DTM, FOM, and orthoimage were re-projected in ESRI ArcGIS 10.7 to minimise the effects of distortion upon the measurements and modelling results presented in Butcher et al. (2023). The sinusoidal projection used has a central meridian of 308.75°E, and is based on the IAU spherical datum for Mars (radius 3396190 m). <br> The data are not georeferenced to any other dataset in this release. Therefore care should be taken in the first instance, with georeferencing as required. The overall quality of the DTM is good, but noise levels vary – check the FOM (see below) and create a shaded relief map to ensure the DTM is adequate for your required use. <br> We note that since we generated the DTM and orthoimage, the HiRISE team also released a DTM generated from the same images, including additional colour orthorectified images (which are used in Butcher et al. 2023). These independently-generated data can be found at: https://www.uahirise.org/dtm/ESP_015947_1370 <br> <strong>DTM Vertical Precision </strong> The vertical precision of the DTM was estimated by Butcher et al. (2023) to be 0.2 m (based on a stereo convergence angle between input images of 14.8°, and assuming an RMS pixel matching error of 0.2 pixels) following the approach of: <br> - Kirk, R. L., et al. (2008), Ultrahigh resolution topographic mapping of Mars with MRO HiRISE stereo images: Meter-scale slopes of candidate Phoenix landing sites, J. Geophys. Res., 113, E00A24, doi:10.1029/2007JE003000. <br> <strong>Figure of Merit (FOM) explanation</strong> Please see 'Readme.txt' for an explanation of values in the Figure of Merit. <br> <strong>Credit </strong> If using the data products included herein, please cite: Butcher et al. (2023) HiRISE images should be credited "Image: NASA/JPL-Caltech/University of Arizona" <br> <br>