First crack at a Prep utility to process SRTM "hgt" data into TerraGear's

intermediate format.

src/Prep/DemChop/Makefile.am

@@ -23,7 +23,7 @@
 #---------------------------------------------------------------------------
 
 
-bin_PROGRAMS = demchop
+bin_PROGRAMS = demchop hgtchop
 
 demchop_SOURCES = \
 	demchop.cxx point2d.hxx
@@ -33,6 +33,14 @@ demchop_LDADD = \
 	-lsgbucket -lsgmisc -lsgdebug -lsgxml -lz
 	$(base_LIBS)
 
+hgtchop_SOURCES = \
+	hgtchop.cxx point2d.hxx
+
+hgtchop_LDADD = \
+	$(top_builddir)/src/Lib/HGT/libHGT.a \
+	-lsgbucket -lsgmisc -lsgdebug -lsgxml -lz
+	$(base_LIBS)
+
 INCLUDES = -I$(top_srcdir)/src -I$(top_srcdir)/src/Lib
 
 # We can't build this with "-O2" (optimization) since this causes a seg fault

src/Prep/DemChop/hgtchop.cxx

@@ -0,0 +1,119 @@
+// hgtchop.cxx -- chop up a hgt file into it's corresponding pieces and stuff
+//                them into the workspace directory
+//
+// Written by Curtis Olson, started March 1999.
+//
+// Copyright (C) 1997  Curtis L. Olson  - curt@flightgear.org
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+//
+// $Id$
+
+
+#include <simgear/compiler.h>
+
+#include STL_STRING
+
+#include <simgear/bucket/newbucket.hxx>
+#include <simgear/debug/logstream.hxx>
+
+#include <HGT/hgt.hxx>
+
+#ifdef _MSC_VER
+#  include <Win32/mkdir.hpp>
+#endif
+
+#include "point2d.hxx"
+
+SG_USING_STD(cout);
+SG_USING_STD(string);
+
+
+int main(int argc, char **argv) {
+    sglog().setLogLevels( SG_ALL, SG_WARN );
+
+    if ( argc != 3 ) {
+	SG_LOG( SG_GENERAL, SG_ALERT, 
+		"Usage " << argv[0] << " <hgt_file> <work_dir>" );
+	exit(-1);
+    }
+
+    string hgt_name = argv[1];
+    string work_dir = argv[2];
+
+    // determine if file is 1arcsec or 3arcsec variety
+    int resolution = 3;
+    SGPath tmp1( hgt_name );
+    SGPath tmp2( tmp1.dir() );
+    string dir = tmp2.file();
+    if ( dir == "1arcsec" ) {
+        resolution = 1;
+    } else if ( dir == "3arcsec" ) {
+        resolution = 3;
+    } else {
+        cout << "ERROR: major problem in directory hierachy or file name!"
+             << endl;
+        cout << "unable to determine resolution." << endl;
+    }
+
+#ifdef _MSC_VER
+    fg_mkdir( work_dir.c_str() );
+#else
+    string command = "mkdir -p " + work_dir;
+    system( command.c_str() );
+#endif
+
+    TGHgt hgt(resolution, hgt_name);
+    hgt.load();
+    hgt.close();
+
+    point2d min, max;
+    min.x = hgt.get_originx() / 3600.0 + SG_HALF_BUCKET_SPAN;
+    min.y = hgt.get_originy() / 3600.0 + SG_HALF_BUCKET_SPAN;
+    SGBucket b_min( min.x, min.y );
+
+    max.x = (hgt.get_originx() + hgt.get_cols() * hgt.get_col_step()) / 3600.0 
+	- SG_HALF_BUCKET_SPAN;
+    max.y = (hgt.get_originy() + hgt.get_rows() * hgt.get_row_step()) / 3600.0 
+	- SG_HALF_BUCKET_SPAN;
+    SGBucket b_max( max.x, max.y );
+
+    if ( b_min == b_max ) {
+	hgt.write_area( work_dir, b_min );
+    } else {
+	SGBucket b_cur;
+	int dx, dy, i, j;
+
+	sgBucketDiff(b_min, b_max, &dx, &dy);
+	cout << "HGT file spans tile boundaries" << endl;
+	cout << "  dx = " << dx << "  dy = " << dy << endl;
+
+	if ( (dx > 20) || (dy > 20) ) {
+	    cout << "somethings really wrong!!!!" << endl;
+	    exit(-1);
+	}
+
+	for ( j = 0; j <= dy; j++ ) {
+	    for ( i = 0; i <= dx; i++ ) {
+		b_cur = sgBucketOffset(min.x, min.y, i, j);
+		hgt.write_area( work_dir, b_cur );
+	    }
+	}
+    }
+
+    return 0;
+}
+
+