PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2007-05-01 NOTE = "Anomalies and discrepancies in the NIR DVD Volume set" END_OBJECT = TEXT END --------------------------------------------------- --------------------------------------------------- Lunar polar coverage and the Clementine NIR Dataset --------------------------------------------------- The processing steps for the NIR mosaics were applied to data from 70 degrees N to 70 degrees S only. The polar regions were processed through 'standard' processing steps only, and the later empirical frame offset and multiplicative corrections were not applied. This was due to multiple overlapping frame coverage and the difficulty in selecting optimal image coverage and deriving a single representative offset correction value for a given frame to be corrected. --------------------------------------------------- --------------------------------------------------- Planetary Data System Data Dictionary Keyword Discrepancies --------------------------------------------------- EASTERNMOST_LONGITUDE: For some images (.IMG files), the value for this keyword may be outside the current valid range. For example, for CD volume CL_5073 (on DVD DCL_5012) the image DATA/NI03S357.IMG contains a cartographically correct value of 360.0132 for EASTERNMOST_LONGITUDE. This is beyond the current allowed maximum of 360. This occurs only for those images that contain the 0/360 longitude line and have a westernmost longitude smaller than 360. At the time of release of this CD volume, the following PDS image label keywords were not yet defined in the PDS Data Dictionary. The definitions are being submitted for inclusion in the dictionary. NULL LOW_REPR_SATURATION LOW_INSTR_SATURATION HIGH_INSTR_SATURATION HIGH_REPR_SATURATION --------------------------------------------------- --------------------------------------------------- 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 Digital Map Products (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 affect 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 and UVVIS Mosaics 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. 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" COORDINATE_SYSTEM_TYPE = "BODY-FIXED ROTATING" COORDINATE_SYSTEM_NAME = "PLANETOGRAPHIC" MAP_PROJECTION_TYPE = "SINUSOIDAL" MAP_RESOLUTION = 303.2334900 MAP_SCALE = 0.1000000 MAXIMUM_LATITUDE = 7.0000000 MINIMUM_LATITUDE = -0.0132000 EASTERNMOST_LONGITUDE = 6.0131998 WESTERNMOST_LONGITUDE = 0.0000000 LINE_PROJECTION_OFFSET = 2123.6345297 SAMPLE_PROJECTION_OFFSET = 4549.5024429 A_AXIS_RADIUS = 1737.4000000 B_AXIS_RADIUS = 1737.4000000 C_AXIS_RADIUS = 1737.4000000 FIRST_STANDARD_PARALLEL = "N/A" SECOND_STANDARD_PARALLEL = "N/A" POSITIVE_LONGITUDE_DIRECTION = EAST CENTER_LATITUDE = 0.0 CENTER_LONGITUDE = 15.0000000 REFERENCE_LATITUDE = "N/A" REFERENCE_LONGITUDE = "N/A" LINE_FIRST_PIXEL = 1 SAMPLE_FIRST_PIXEL = 1 LINE_LAST_PIXEL = 2127 SAMPLE_LAST_PIXEL = 1844 MAP_PROJECTION_ROTATION = 0.0000000 VERTICAL_FRAMELET_OFFSET = "N/A" HORIZONTAL_FRAMELET_OFFSET = "N/A" 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, Clementine Basemap, and Clementine UVVIS 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 & DVD VOLUMES THAT CONFORM TO THE ISO-9660 STANDARDS Eric M. Eliason 3/1/1997 Names of files stored on an ISO-9660 formatted CD or DVDs 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 various operating systems 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 files (index.tab and cumindex.tab) and the source image index file (srcindx.tab on final volume) 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. ########################################################### ###########################################################