PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2017-05-12 NOTE = "Initial delivery." END_OBJECT = TEXT END MESSENGER Digital Elevation Model EXTRAS Directory Contents March 14, 2017 The EXTRAS directory within the Mercury Digital Elevation Model (DEM) MESSDEM_1001 data volume contains data products and information that are ancillary to the volume, but could be useful to users of the science data products. EXTRAS/REGIONAL/ This subdirectory contains subdirectories for the ASU DEM GeoTIFF format products. The ASU primary DEMs (*_DM_*) have GeoTIFF files associated with them, which are placed in this directory. These products follow the same filenaming convention as the DEM products, but have 'T' in the product code field and a .TIF file extension. Other associated ASU DEM products are provided only in GeoTIFF format and are also archived here. Therefore, there are more GeoTIFF files than there are DEM/REGIONAL/IMG/*.IMG files. See the SIS for details. MSGR_DEM_ASU_EQ____T_V.TIF aaaaa = the region covered by the product bb = the stereo pair mm = the product type ss = the map scale For example: EXTRAS/REGIONAL/MSGR_DEM_ASU_EQ_CATLS01_DM_85_T_V01.TIF PDS-type label files, thought not required for products in the EXTRAS directory, are included in this case since they contain useful information. They are named identically to the GeoTIFF files, but have .LBL as the file extension. These should be treated as associated metadata products rather than bonafide PDS labels. The DEM (*_DM_*.TIF) GeoTIFF products are 32-bit images. Most general-purpose image viewers are unable to properly render TIFF images of this bit depth. It is recommended that users open these files using an application that is designed to handle images with larger bit depth, such as professional GIS applications. ASU also provides free-formatted text files that provide information on the MDIS source products used to create the DEMs and other processing information. These have product type (mm) of 'RM', product code of 'S' and .TXT file extensions. For example: EXTRAS/REGIONAL/MSGR_DEM_ASU_EQ_CATLS01_RM_85_S_V01.TXT See the SIS "Product Naming Conventions" section for a more detailed description of the naming convention and the meanings of its constituent fields. EXTRAS/ISIS/ This subdirectory contains supporting files produced by the USGS Integrated Software for Imagers and Spectrometers (ISIS). The USGS provides the ISIS software free to the public (http://isis.astrogeology.usgs.gov). ISIS Cube history files and ISIS metadata files are included here. When creating image products, ISIS creates files of metadata that describe the image. These metadata files have an '.LBL' ending like PDS labels, but they should not be confused with them. ISIS metadata files can be re-read by ISIS software in order to specify the format of the image for proper rendering. The following instructions are provided to create an ISIS compatible DEM product that can be used as a shape model for Mercury: a. Copy MESSDEM_1001/DEM/GLOBAL/IMG/MSGR_DEM_USG_SC_I_V02.IMG to the directory containing the ISIS detached labels. b. Run the ISIS application demprep to produce the ISIS-compatible shape model: i. demprep from=MSGR_DEM_USG_SC_I_V02.IMG.RADIUS.LBL to=MSGR_DEM_USG_SC_I_V02.PREP.CUB c. It is now ready to use as an ISIS shape model for any Mercury mapping processing in ISIS. Here is an example on how to apply the shape model in spiceinit for an MDIS image: i. spiceinit from=EN0210451707M.CUB shape=user model=MSGR_DEM_USG_SC_I_V02.PREP.CUB Note that the polar DEMs can be used as an ISIS shape model directly and do not require step b) above (i.e., demprep should not be run on the polar DEMs). The *.LBL files in the EXTRAS/ISIS/ directory are ISIS labels, not PDS labels and have a different format and content. EXTRAS/QUAD/ This subdirectory contains the DLR (German Aerospace Center) DEM images in GeoTIFF and Portable Network Graphics (PNG) formats. Each product in the DEM/QUAD/IMG/ directory has an associated GeoTIFF product archived in this directory. There is also a PNG file for each DEM product. (In the cases of the H03 and H05 products, PNGs are provided only for the Lambert Conformal projection versions of the DEM products.) The GeoTIFF and PNG files in this directory follow the same naming convention as their associated primary DEM products, except that they have a 'T' for GeoTiff and a 'P' for PNG respectively for the product code field in place of the primary product's 'I'.