PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1998-09-12 NOTE = "Anomalies and discrepancies in the CD Volume set" END_OBJECT = TEXT END ################################################################# CD COUNT Documents on previous HiRes Mosaic CDs refer to the total CD count as 20, consistent with a single CD per pole, each using all available data pertinent to a given pole. However, it was decided during completion of the polar mosaics to generate separate mosaics for apoapsis and periapsis data, which provides a more uniform appearance and quality. This brings the total CD count to 22. IMAGE NAMING CONVENTION Clementine HiRes mosaics produced at 20 m/pixel scale have names starting with "H"; this is not consistent with the naming scheme developed by the USGS, which recently designated "E" for 20 m/pixel Clementine products. Also, although the USGS has no designation for 30 m/pixel scale, the use of "G" for the 30 m/pixel polar mosaics is contrary to the USGS arrangement in which resolution decreases with alphabetic order. MISSING UV/Vis SUB-POLAR CONTEXT A very few of the sub-polar mosaic JPEG context images appear to have portions missing UV/Vis data. These "holes" are, in fact, present in the original UV/Vis basemaps and represent lack of UV/Vis and NIR images of sufficient quality. MISCELLANEOUS The following ancillary file errors are found on CL_6019 and CL_6021: 1. Missing END statement in dsmap.cat. 2. Missing closing quote for MCEWENETAL1997 reference in refs.cat. 3. Missing closing quote for column 1's description section. ADDITIONAL ERRATA INFORMATION Presented below are discussions by Eric Eliason which address, first, discrepancies in cartographic offset parameter definitions in the various planetary DIMs and, second, variations in file name conventions and the impact of this with ISO-9660 CD standards. ################################################################# DISCREPANCIES OF PROJECTION OFFSET PARAMETERS AMONG USGS-PRODUCED PLANETARY DIGITAL GLOBAL MAPS Eric M. Eliason 7/1/1997 The Issue --------- This report discusses discrepancies in map projection parameters found in the PDS labels on the Mars MDIM, Magellan F-Map (Venus), and Clementine Base Map Mosaic (Earth's Moon) produced by the USGS Astrogeology Team. This report is important for individuals needing to know the precise definition of the map projection and cartographic parameters that describe the image map. There are differences in the cartographic parameters in each of the data products that effect the algorithms defining the relationship between line and sample position in the image array and the latitude and longitude position on the planet surface. Specifically, the LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET parameters have inconsistent definitions among these data sets. Additionally, as discussed below there are differences in the keywords names used to describe the map projection parameters on the PDS labels due to the evolution of PDS standards. Data Products In Question ------------------------- The Mars MDIM, Magellan F-Map, and Clementine Basemap Mosaic exist on CD media and are available for wide distribution to the NASA science community. These data sets contain global Mosaicked Digital Image Models (MDIM). The data sets are organized according to a "tiling" scheme that divides the planet into tiles (or quadrangles). Each tile represents a specific area on the planet. A tile is stored as a PDS-labeled image file. For more information on the data products, refer to the "volinfo.txt" file located in the document directory on the CD volume sets. [Note: The Clementine HiRes Mosaics also adopt the same keyword convention.] Cartographic Keywords in the PDS Labels --------------------------------------- The "IMAGE_MAP_PROJECTION" object contained in a PDS label provides the cartographic parameters necessary to define any map projection. For the Sinusoidal Equal-Area Projection only a subset of the cartographic keywords are required and parameters not applicable will contain "N/A" in the fields. The list below shows a typical IMAGE_MAP_PROJECTION group of keywords. For precise definitions of the keywords, refer to the volinfo.txt file (located in the document directory) and the dsmap.cat file (located in the catalog directory.) OBJECT = IMAGE_MAP_PROJECTION ^DATA_SET_MAP_PROJECTION = "DSMAP.CAT" MAP_PROJECTION_TYPE = SINUSOIDAL MAP_RESOLUTION = 1408.1316 MAP_SCALE = 0.075 MAXIMUM_LATITUDE = 38.00000 MINIMUM_LATITUDE = 35.99000 EASTERNMOST_LONGITUDE = 146.01088 WESTERNMOST_LONGITUDE = 144.00000 LINE_PROJECTION_OFFSET = -53510.0039 SAMPLE_PROJECTION_OFFSET = -6837.0801 A_AXIS_RADIUS = 6051.00 B_AXIS_RADIUS = 6051.00 C_AXIS_RADIUS = 6051.00 FIRST_STANDARD_PARALLEL = "N/A" SECOND_STANDARD_PARALLEL = "N/A" POSITIVE_LONGITUDE_DIRECTION = EAST CENTER_LATITUDE = 0.00000 CENTER_LONGITUDE = 150.00000 REFERENCE_LATITUDE = "N/A" REFERENCE_LONGITUDE = "N/A" LINE_FIRST_PIXEL = 1 SAMPLE_FIRST_PIXEL = 1 LINE_LAST_PIXEL = 2830 SAMPLE_LAST_PIXEL = 2410 MAP_PROJECTION_ROTATION = 0.00000 VERTICAL_FRAMELET_OFFSET = 1 HORIZONTAL_FRAMELET_OFFSET = 6 END_OBJECT = IMAGE_MAP_PROJECTION END Because of the change in PDS standards the IMAGE_MAP_PROJECTION group is different between the Mars MDIM products and the Magellan F-Map and Lunar MDIM products. The Mars MDIM products were created before the "final" cartographic projection keywords were defined and so they are different from the F-MAP and Lunar MDIM products. Here is a list of the differences in keyword names: Mars MDIM Label F-MAP / Lunar MDIM Label ----------------------------------------------------------------- IMAGE_ID (in main label body) changed to PRODUCT_ID IMAGE_MAP_PROJECTION_CATALOG changed to IMAGE_MAP_PROJECTION DATA_SET_MAP_PROJECTION_CATALOG changed to DATA_SET_MAP_PROJECTION X_AXIS_FIRST_PIXEL changed to LINE_LAST_PIXEL X_AXIS_LAST_PIXEL changed to LINE_LAST_PIXEL Y_AXIS_FIRST_PIXEL changed to SAMPLE_FIRST_PIXEL Y_AXIS_LAST_PIXEL changed to SAMPLE_LAST_PIXEL X_AXIS_PROJECTION_OFFSET changed to LINE_PROJECTION_OFFSET Y_AXIS_PROJECTION_OFFSET changed to SAMPLE_PROJECTION_OFFSET Discrepancies with Offset Parameters ------------------------------------- The LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET parameters have inconsistent definitions among the Clementine, F- Map and Mars MDIM data products. This section describes the differences. For the Mars MDIM, the offset parameters (called X_AXIS_PROJECTION_OFFSET and Y_AXIS_PROJECTION_OFFSET) are used to define line and sample number as a function of latitude and longitude: line = INT(X_AXIS_PROJECTION_OFFSET - LAT*MAP_RESOLUTION + 1.0) sample = INT(Y_AXIS_PROJECTION_OFFSET - (LON - CENTER_LONGITUDE)*MAP_RESOLUTION*COS(LAT) + 1.0) Note that the addition of 1.0 is part of the equation. This means the X_AXIS_PROJECTION_OFFSET and Y_AXIS_PROJECTION_OFFSET are relative to line and sample 0,0 in the image array. Because the direction of positive longitude is to the west for Mars, there is a "-" after the Y_AXIS_PROJECTION_OFFSET in the equation. For the F-MAP and Clementine basemap the equations are defined as: line = INT(LINE_PROJECTION_OFFSET - LAT*MAP_RESOLUTION) sample = INT(SAMPLE_PROJECTION_OFFSET + (LON - CENTER_LONGITUDE)*MAP_RESOLUTION*COS(LAT)) Note that the addition of 1.0 is not part of the equation. This means that the offset parameters are relative to line and sample 1,1. Because the direction of positive longitude is to the east for Venus and the Moon, there is a "+" after the SAMPLE_PROJECTION_OFFSET term. An additional discrepancy exists in the F-MAP volume set. The LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET parameters are actually the negative of the value that they should be. A software patch has been included on the F-MAP CD-ROMs to correct the projection offset keywords. The name of the program is PATH and it is stored in the SOFTWARE directory on the F-MAP volumes. ################################################################# ################################################################# UPPER-CASE AND LOWER-CASE FILE NAMES AND DIRECTORIES ON CD VOLUMES THAT CONFORM TO THE ISO-9660 STANDARDS Eric M. Eliason 3/1/1997 Names of files stored on an ISO-9660 formatted CD are different among computer systems and operating systems. Some systems use lower-case file names while other systems use upper-case file names. Here is a list of how popular operating behave with file names: Sun/Solaris - File names and folders are lower-case lettering Macintosh - File names and folders are upper-case lettering PC/Windows 95 - File names and folders have the first letter upper-case followed by lower-case lettering. PC/MS-DOS - File names and folders are upper-case lettering PC/Windows 3.1 - File names and folders are lower-case lettering Because of the inconsistent case lettering of file names it was decided to provide file and volume names in the image index file (imgindx.tab) and the source image index file (srcindx.tab) to upper-case lettering. Users desiring to build applications around these tables will need to convert the file name to the appropriate case for their systems. ################################################################# ################################################################# VALIDATION PERFORMED BY THE PLANETARY DATA SYSTEM Eric Eliason 9/25/99 The anomalies reported here are intended primarily for data product developers that might use the Clementine HiRes CD-ROMs as a model for future data products. The original peer review of these data products did not identify the items listed below as problems and are considered inconsequential to the overall usefulness of the data. 1) PDS standards require all files to be labeled. The following files should have been provided with a PDS label: brwstxt.htm, clemlogo.gif, index.htm, msss.gif, All *.htm and *.jpg located in the browse subdirectory of each volume. 2) The index files located in the index directory of these volumes do not fully comply with PDS naming conventions: imgindx.lbl should be named imgindex.lbl imgindx.tab should be named imgindex.tab srcindx.lbl should be named srcindex.lbl srcindx.tab should be named srcindex.tab 3) The html files on these volumes have unix-style line terminators (line-feed characters at the end of each line) but should have used the DOS-style convention of carriage-return line-feed characters to mark the end of each line.