- S\bSP\bPL\bLA\bAT\bT!\b! imports topographic data in the form of SPLAT Data
- Files (SDFs) that may be generated from a number of infor-
- mation sources. In the United States, SPLAT Data Files
- are most often derived from U.S. Geological Survey Digi-
- tal Elevation Models (DEMs) using the u\bus\bsg\bgs\bs2\b2s\bsd\bdf\bf utility
- included with S\bSP\bPL\bLA\bAT\bT!\b!. USGS Digital Elevation Models com-
- patible with this utility are available at no cost via the
- Internet at: _\bh_\bt_\bt_\bp_\b:_\b/_\b/_\be_\bd_\bc_\b-
- _\bs_\bg_\bs_\b9_\b._\bc_\br_\b._\bu_\bs_\bg_\bs_\b._\bg_\bo_\bv_\b/_\bg_\bl_\bi_\bs_\b/_\bh_\by_\bp_\be_\br_\b/_\bg_\bu_\bi_\bd_\be_\b/_\b1_\b__\bd_\bg_\br_\b__\bd_\be_\bm_\b-
- _\bf_\bi_\bg_\b/_\bi_\bn_\bd_\be_\bx_\b1_\bm_\b._\bh_\bt_\bm_\bl.
-
- SPLAT Data Files contain topographic elevations to the
- nearest meter above mean sea level for 1-degree by
- 1-degree regions of the earth with a resolution of 3-arc
- seconds. SDF files can be read in either standard format
- (_\b._\bs_\bd_\bf) as generated by the u\bus\bsg\bgs\bs2\b2s\bsd\bdf\bf utility, or in bzip2
- compressed format (_\b._\bs_\bd_\bf_\b._\bb_\bz_\b2). Since uncompressed files
- can be slightly faster to load than compressed files,
+ S\bSP\bPL\bLA\bAT\bT!\b! imports topographic data in the form of SPLAT Data
+ Files (SDFs). These files may be generated from a number
+ of information sources. In the United States, SPLAT Data
+ Files can be generated through U.S. Geological Survey
+ Digital Elevation Models (DEMs) using the u\bus\bsg\bgs\bs2\b2s\bsd\bdf\bf utility
+ included with S\bSP\bPL\bLA\bAT\bT!\b!. USGS Digital Elevation Models com-
+ patible with this utility may be downloaded from:
+ _\bh_\bt_\bt_\bp_\b:_\b/_\b/_\be_\bd_\bc_\bf_\bt_\bp_\b._\bc_\br_\b._\bu_\bs_\bg_\bs_\b._\bg_\bo_\bv_\b/_\bp_\bu_\bb_\b/_\bd_\ba_\bt_\ba_\b/_\bD_\bE_\bM_\b/_\b2_\b5_\b0_\b/.
+
+ Significantly better resolution can be obtained through
+ the use of SRTM-3 Version 2 digital elevation models.
+ These models are the result of the STS-99 Space Shuttle
+ Radar Topography Mission, and are available for most popu-
+ lated regions of the Earth. SPLAT Data Files may be gen-
+ erated from SRTM data using the included s\bsr\brt\btm\bm2\b2s\bsd\bdf\bf utility.
+ SRTM-3 Version 2 data may be obtained through anonymous
+ FTP from: _\bf_\bt_\bp_\b:_\b/_\b/_\be_\b0_\bs_\br_\bp_\b0_\b1_\bu_\b._\be_\bc_\bs_\b._\bn_\ba_\bs_\ba_\b._\bg_\bo_\bv_\b:_\b2_\b1_\b/_\bs_\br_\bt_\bm_\b/_\bv_\be_\br_\bs_\bi_\bo_\bn_\b2_\b/
+
+ Despite the higher accuracy that SRTM data has to offer,
+ some voids in the data sets exist. When voids are
+ detected, the s\bsr\brt\btm\bm2\b2s\bsd\bdf\bf utility replaces them with corre-
+ sponding data found in existing SDF files (that were pre-
+ sumably created from earlier USGS data through the
+ u\bus\bsg\bgs\bs2\b2s\bsd\bdf\bf utility). If USGS-derived SDF data is not avail-
+ able, voids are handled through adjacent pixel averaging,
+ or direct replacement.
+
+ SPLAT Data Files contain integer value topographic eleva-
+ tions (in meters) referenced to mean sea level for
+ 1-degree by 1-degree regions of the earth with a resolu-
+ tion of 3-arc seconds. SDF files can be read in either
+ standard format (_\b._\bs_\bd_\bf) as generated by the u\bus\bsg\bgs\bs2\b2s\bsd\bdf\bf and
+ s\bsr\brt\btm\bm2\b2s\bsd\bdf\bf utilities, or in bzip2 compressed format
+ (_\b._\bs_\bd_\bf_\b._\bb_\bz_\b2). Since uncompressed files can be processed
+ slightly faster than files that have been compressed,