USGS

Venus Mapping White Paper

Open-File Report 95-519


Appendix 3

Useful Programs and Data Files

This section lists some other programs and data files available from ceps.nasm.edu over anonymous ftp. The source files can be compiled as described in Appendix 1 or run directly from the executables provided in the ftp directory. For any questions or problems, contact Bruce Campbell (campbell@ceps.nasm.edu). The output of all mosaicking programs are simple 8-bit raster files with no header information, but the mapping data can be recovered from the framelet headers on the CD-ROM.

The ascii data files are for use in creating radar correlation charts for Venus backscatter data. The terrestrial AIRSAR data do not have error values listed with them, because the standard deviations vary with the degree of multilook averaging. Typical errors are about ±1 dB for these measurements. All backscatter coefficients are HH polarization interpolated 12.6-cm values derived from 6- and 24-cm data (eq. 4). See Campbell et al. [1993] for a discussion of the surface texture on these lava flows.

PROGRAMS:

midr.f --- Fortran program which mosaics all or some of the 56 tiles of an F, C1, C2, or C3 MIDR image directly from the CD-ROM. Prompts for destination file name and the tile coordinates (1-8 left to right; 1-7 top to bottom).

fmap.f --- A developmental Fortran program which mosaics and shrinks the FMAP tiles from a CD-rom to 150 m resolution. The resulting mosaic is about 8000 pixels square, which is typically a good size for filmwriters. The output map lower left corner corresponds to the edge of the lower left fmap tile. All other sides have some padding.

DATA FILES:

muhl.law --- ascii data file of incidence angle (column 1) and backscatter coefficient in decibels (column 2) for the average behavior of Venus derived by Muhleman [1964]. This backscatter law is the correct one proposed by Muhleman; note that the coefficients used in the Magellan data processing are slightly different.

hh.1920aa.s --- ascii file of incidence angle versus backscatter coefficient (dB) for the 1920 a'a lava flow from Mauna Iki on Kilauea volcano.

hh.miaa.s --- ascii file of incidence angle versus backscatter coefficient (dB) for an a'a lava flow near the summit of Mauna Iki.

hh.1920pah.s --- ascii file of incidence angle versus backscatter coefficient (dB) for the 1920 pahoehoe lava flow from Mauna Iki.

hh.cald.s --- ascii file of incidence angle versus backscatter coefficient (dB) for the large pahoehoe flows on the floor of Kilauea Caldera, Hawaii.

hh.pond.s --- ascii file of incidence angle versus backscatter coefficient (dB) for the very smooth lava flows ponded in the floors of Halemaumau and Kilauea Iki craters, Hawaii.