Solar System Generic Tiled DSK Files ============================================================================= This "aareadme.txt" file describes the contents of the kernels/dsk/tiled directory of the Solar System Generic SPICE Kernel Dataset. It also provides the file naming conventions used for the Solar System Generic Tiled DSK kernels. It was last modified on June 11th, 2025 by Alfredo Escalante Lopez, ESAC/ESA. Brief Summary -------------------------------------------------------- This directory contains the tiled SPICE Digital Shape-Kernel files for Solar System Generic bodies. In order to implement the maximum spatial resolution available in Digital Elevation Models for the DSKs of various natural bodies, a tiled version consisting of a set of 32 (latitudinal divisions) by 32 (longitudinal divisions) DSKs conforming the whole shape model of the targets have been produced. File naming conventions -------------------------------------------------------- The naming scheme for the Natural Bodies DSKs is: BODY_PRO[_DEM][_YY][_XX]_vNN.bds where BODY body: mars for Mars mercury for Mercury moon for Moon earth for Earth PRO producer: mola for Mars Global Surveyor MOLA data. messenger for MESSENGER data. lola for Lunar Reconnaissance Orbiter LOLA data. sldem for LRO LOLA and SELENE Kaguya merged data. etopo for NOAA Earth Topography data. DEM Digital Elevation Model spatial resolution (required; e.g. dem_118m) YY latitudinal tile index (required; e.g. 01) XX longitudinal tile index (required; e.g. 01) NN version number (required; e.g. 01) Current DSK Kernels Set -------------------------------------------------------- mars_mola_dem_463m_YY_XX_vNN.bds Contains Mars tiled shape data based on MOLA data processed and generated by ESA SPICE Service (ESS). mercury_messenger_dem_665m_YY_XX_vNN.bds Contains Mercury tiled shape data based on MESSENGER data processed and generated by ESA SPICE Service (ESS). moon_lola_dem_118m_YY_XX_vNN.bds Contains Moon tiled shape data based on LOLA data processed and generated by ESA SPICE Service (ESS). moon_sldem_dem_59m_YY_XX_vNN.bds Contains Moon tiled shape data based on LOLA and SELENE merged data processed and generated by ESA SPICE Service (ESS). earth_etopo_dem_926m_YY_XX_vNN.bds Contains Earth tiled shape data based on NOAA bare-Earth bedrock Topography data processed and generated by ESA SPICE Service (ESS). Kernel File Details -------------------------------------------------------- The contents of any DSK file may be easily determined using the 'dskbrief' utility program, Example: % dskbrief Descriptive information about how/why/when an DSK file was created is usually available in the 'comment area' of the file. This may be viewed using the 'commnt' utility program available in all copies of the SPICE Toolkit. Use the '-r' option to read the comments. Example: % commnt -r All binary DSK files (*.bds) contained in this directory are little-endian (LTL-IEEE) binary files. These DSK files have been produced by ESA SPICE Service. About the DSK generation ------------------------------------------------------------------------ In order to retain the maximum spatial resolution of the source data, a set of tiled DSKs have been produced to provide full coverage of the target. The body is separated in 32 by 32 latitudinal and longitudinal divisions, each of them covering 11.25 degrees longitude and 5.625 degrees latitude. The latitudinal sector YY and longitudinal sector XX of the tiled grid is indicated in the DSK filename. For example: moon_lola_dem_118m_YY_XX_v02.bds For the moon_lola_118m and mars_mola_463m tiled sets, the tile 01_01 covers latitude range from 84.375 to 90.0 and longitude range -180.0 to -168.75, the tile 01_02 -- covers latitude range from 84.375 to 90.0 and longitude range from -168.75 to -157.5, and the tile 32_32 -- covers latitude range from -90.0 to -84.375 and longitude range from 168.75 to 180.0. For the set mercury_messenger_665m, the tile 01_01 covers latitude range from 84.375 to 90.0 and longitude range 0.0 to 11.25, the tile 01_02 -- covers latitude range from 84.375 to 90.0 and longitude range from 11.25 to 22.5, and the tile 32_32 -- covers latitude range from -90.0 to -84.375 and longitude range from 348.75 to 360.0. For moon_sldem_59m tiled set, in order to retain the maximum spatial resolution of the source data, a set of tiled DSKs have been produced to provide -60 to +60 degrees latitude coverage of the Moon. The Moon is separated in 32 by 64 latitudinal and longitudinal divisions, each of them covering 5.625 degrees longitude and 3.75 degrees latitude. The latitudinal sector YY and longitudinal sector XX of the tiled grid is indicated in the DSK filename. moon_sldem_dem_59m_YY_XX_v01.bds For example, the tile 01_01 covers latitude range from 56.25 to 60.0 and longitude range -180.0 to -174.375, the tile 01_02 -- covers latitude range from 56.25 to 60.0 and longitude range from -174.375 to -168.75, and the tile 32_64 -- covers latitude range from -60.0 to -56.25 and longitude range from 174.375 to 180.0. In order to make sure there are no gaps at the boundaries between tiles, each segment has been created using ``padding'' including additional plates extending slightly beyond the segments boundaries (consecutive tiles overlap by few rows of plates). This ensures that no ray emanating from the origin and hitting the sphere within the segment's longitude-latitude coverage can miss all of the segment's plates. For more details see Segment Coverage Errors section in [1]. Extra rows have been only added at the northern and southern boundaries to fix the issue indicated in DSK required reading, the minimum required to fix the latitude gap at the boundary segment center 'above' and 'below' each tile has been added. No padding has been added at the meridian boundaries as in that case the longitude of the east and west boundary segments is constant. Other directory contents -------------------------------------------------------- aareadme.txt This file. Particulars -------------------------------------------------------- Please note that in order to use DSK data you need to use N0066 or later Toolkits. Contact Information -------------------------------------------------------- If you have any questions regarding this file contact the ESA SPICE Service (ESS) at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@cosmos.esa.int References and required readings -------------------------------------------------------- 1. ``DSK Required Reading'', NAIF Document End of aareadme file.