Contributions from David Megginson.

- increased maximum areas to 128 (for future growth), and added Road
  and Railroad areas
- changed the method of calculating the triangle centre in
  poly_support.hxx
- added a has_holes() method to polygon.hxx
- added a new library, e00, for reading ArcInfo e00 files (i.e. the
  free online ones from DCW and GeoGratis); it needs more work
- added a new prep utility, e00lines, for creating textured polygons
  out of e00 line data (with user-specified width and area type); this
  is useful for roads, railroads, rivers, and utility lines

configure.in

@@ -302,6 +302,7 @@ AC_OUTPUT( \
 	src/Lib/Makefile \
 	src/Lib/Array/Makefile \
 	src/Lib/DEM/Makefile \
+	src/Lib/e00/Makefile \
 	src/Lib/Geometry/Makefile \
 	src/Lib/landcover/Makefile \
 	src/Lib/Optimize/Makefile \
@@ -313,6 +314,7 @@ AC_OUTPUT( \
 	src/Prep/DemChop/Makefile \
 	src/Prep/DemInfo/Makefile \
 	src/Prep/DemRaw2ascii/Makefile \
+	src/Prep/E00Lines/Makefile \
 	src/Prep/GenAirports/Makefile \
 	src/Prep/GSHHS/Makefile \
 	src/Prep/MergerClipper/Makefile \

src/BuildTiles/Clipper/clipper.cxx

@@ -38,21 +38,18 @@ FG_USING_STD(cout);
 #define MASK_CLIP 1
 
 
-// Constructor
+// Constructor.
-FGClipper::FGClipper( void ) {
+FGClipper::FGClipper() {
 }
 
 
-// Destructor
+// Destructor.
-FGClipper::~FGClipper( void ) {
+FGClipper::~FGClipper() {
 }
 
 
-// Initialize Clipper (allocate and/or connect structures)
+// Initialize the clipper (empty all the polygon buckets.)
 bool FGClipper::init() {
-    // v_list.num_vertices = 0;
-    // v_list.vertex = new gpc_vertex[FG_MAX_VERTICES];;
-
     for ( int i = 0; i < FG_MAX_AREA_TYPES; ++i ) {
 	polys_in.polys[i].clear();
     }
@@ -61,7 +58,7 @@ bool FGClipper::init() {
 }
 
 
-// Load a polygon definition file
+// Load a polygon definition file.
 bool FGClipper::load_polys(const string& path) {
     string poly_name;
     AreaType poly_type = DefaultArea;
@@ -78,9 +75,6 @@ bool FGClipper::load_polys(const string& path) {
 	exit(-1);
     }
 
-    // gpc_polygon *poly = new gpc_polygon;
-    // poly->num_contours = 0;
-    // poly->contour = NULL;
     FGPolygon poly;
 
     Point3D p;
@@ -133,8 +127,6 @@ bool FGClipper::load_polys(const string& path) {
 		// cout << "poly pt = " << p << endl;
 		poly.add_node( i, p );
 	    }
-
-	    // gpc_add_contour( poly, &v_list, hole_flag );
 	}
 
 	in >> skipcomment;
@@ -142,10 +134,6 @@ bool FGClipper::load_polys(const string& path) {
 
     int area = (int)poly_type;
 
-    // if ( area == OceanArea ) {
-    // TEST - Ignore
-    // } else 
-
     add_poly(area, poly);
 
     // FILE *ofp= fopen("outfile", "w");
@@ -154,7 +142,7 @@ bool FGClipper::load_polys(const string& path) {
     return true;
 }
 
-
+// Add a polygon to the clipper.
 void FGClipper::add_poly( int area, const FGPolygon &poly )
 {
     if ( area < FG_MAX_AREA_TYPES ) {
@@ -167,7 +155,7 @@ void FGClipper::add_poly (int area, const FGPolygon &poly)
 }
 
 
-// remove any slivers from in polygon and move them to out polygon.
+// Move slivers from in polygon to out polygon.
 void FGClipper::move_slivers( FGPolygon& in, FGPolygon& out ) {
     // traverse each contour of the polygon and attempt to identify
     // likely slivers
@@ -221,7 +209,9 @@ void FGClipper::move_slivers( FGPolygon& in, FGPolygon& out ) {
 }
 
 
-// for each sliver contour, see if a union with another polygon yields
+// Attempt to merge slivers into a list of polygons.
+//
+// For each sliver contour, see if a union with another polygon yields
 // a polygon with no increased contours (i.e. the sliver is adjacent
 // and can be merged.)  If so, replace the clipped polygon with the
 // new polygon that has the sliver merged in.
@@ -289,7 +279,8 @@ void FGClipper::merge_slivers( FGPolyList& clipped, FGPolygon& slivers ) {
 }
 
 
-// Do actually clipping work
+// Clip all the polygons against each other in a priority scheme based
+// on order of the polygon type in the polygon type enum.
 bool FGClipper::clip_all(const point2d& min, const point2d& max) {
     FGPolygon accum, tmp;
     FGPolygon slivers, remains;
@@ -339,7 +330,6 @@ bool FGClipper::clip_all(const point2d& min, const point2d& max) {
     }
 #endif
 
-    // int count = 0;
     // process polygons in priority order
     for ( int i = 0; i < FG_MAX_AREA_TYPES; ++i ) {
 	cout << "num polys of type (" << i << ") = " 
@@ -377,13 +367,6 @@ bool FGClipper::clip_all(const point2d& min, const point2d& max) {
 	    }
 #endif
 
-	    // clip current polygon against previous higher priority
-	    // stuff
-
-	    // result_diff = new gpc_polygon;
-	    // result_diff->num_contours = 0;
-	    // result_diff->contour = NULL;
-
 	    FGPolygon result_union, result_diff;
 
 	    if ( accum.contours() == 0 ) {

src/BuildTiles/Clipper/clipper.hxx

@@ -45,41 +45,35 @@ FG_USING_STD(string);
 FG_USING_STD(vector);
 
 
-// typedef vector < gpc_polygon * > gpcpoly_container;
+#define FG_MAX_AREA_TYPES 128	// FIXME also defined in
-// typedef gpcpoly_container::iterator gpcpoly_iterator;
-// typedef gpcpoly_container::const_iterator const_gpcpoly_iterator;
-
-
-#define FG_MAX_AREA_TYPES 40	// FIXME also defined in
                                 // MergerClipper/clipper.hxx
 #define EXTRA_SAFETY_CLIP
-// #define FG_MAX_VERTICES 100000
 
 
-class FGPolyList {
+class FGPolyList
+{
 public:
     poly_list polys[FG_MAX_AREA_TYPES];
     FGPolygon safety_base;
 };
 
 
-class FGClipper {
+class FGClipper 
+{
 
 private:
 
-    // gpc_vertex_list v_list;
-    // static gpc_polygon poly;
     FGPolyList polys_in, polys_clipped;
 
 public:
 
-    // Constructor
+    // Constructor.
     FGClipper (void);
 
-    // Destructor
+    // Destructor.
     ~FGClipper (void);
 
-    // Initialize Clipper (allocate and/or connect structures)
+    // Initialize Clipper (allocate and/or connect structures.)
     bool init();
 
     // Load a polygon definition file
@@ -88,20 +82,20 @@ public:
     // Add a polygon.
     void add_poly(int area, const FGPolygon &poly);
 
-    // remove any slivers from in polygon and move them to out
+    // Remove any slivers from in polygon and move them to out
     // polygon.
     void move_slivers( FGPolygon& in, FGPolygon& out );
 
-    // for each sliver contour, see if a union with another polygon
+    // For each sliver contour, see if a union with another polygon
     // yields a polygon with no increased contours (i.e. the sliver is
     // adjacent and can be merged.)  If so, replace the clipped
     // polygon with the new polygon that has the sliver merged in.
     void merge_slivers( FGPolyList& clipped, FGPolygon& slivers );
     
-    // Do actually clipping work
+    // Do actual clipping work.
     bool clip_all(const point2d& min, const point2d& max);
 
-    // return output poly list
+    // Return output poly list
     inline FGPolyList get_polys_clipped() const { return polys_clipped; }
 };
 

src/BuildTiles/Main/main.cxx

@@ -64,9 +64,7 @@ FG_USING_STD(vector);
 vector<string> load_dirs;
 
 
-/**
+// Translate USGS land cover values into TerraGear area types.
- * Translate USGS land cover into TerraGear.
- */
 static AreaType translateUSGSCover (int usgs_value)
 {
   switch (usgs_value) {
@@ -127,7 +125,7 @@ static AreaType translateUSGSCover (int usgs_value)
 }
 
 
-// do actual scan of directory and loading of files
+// Scan a directory and load polygon files.
 static int actual_load_polys( const string& dir,
 			      FGConstruct& c,
 			      FGClipper& clipper ) {
@@ -172,8 +170,10 @@ static int actual_load_polys( const string& dir,
 }
 
 
-// Merge a polygon with an existing one if possible, append a new
+// Add a polygon to a list, merging if possible.
-// one otherwise; this function is used by actual_load_landcover, below,
+//
+// Merge a polygon with an existing one if possible, append a new one
+// otherwise; this function is used by actual_load_landcover, below,
 // to reduce the number of separate polygons.
 static void inline add_to_polys ( FGPolygon &accum, const FGPolygon &poly) {
     if ( accum.contours() > 0 ) {
@@ -184,7 +184,7 @@ static void inline add_to_polys ( FGPolygon &accum, const FGPolygon &poly) {
 }
 
 
-// Generate polygons from land-cover raster.  Horizontally- or
+// Generate polygons from la and-cover raster.  Horizontally- or
 // vertically-adjacent polygons will be merged automatically.
 static int actual_load_landcover ( LandCover &cover, FGConstruct & c,
 				   FGClipper &clipper ) {
@@ -261,8 +261,8 @@ static int actual_load_landcover ( LandCover &cover, FGConstruct & c,
 }
 
 
-// load all 2d polygons matching the specified base path and clip
+// load all 2d polygons from the specified load disk directories and
-// against each other to resolve any overlaps
+// clip against each other to resolve any overlaps
 static int load_polys( FGConstruct& c ) {
     FGClipper clipper;
 
@@ -304,8 +304,8 @@ static int load_polys( FGConstruct& c ) {
 }
 
 
-// load regular grid of elevation data (dem based), return list of
+// Load elevation data from a DEM file, a regular grid of elevation
-// fitted nodes
+// data--dem based) and return list of fitted nodes.
 static int load_dem( FGConstruct& c, FGArray& array) {
     point_list result;
     string base = c.get_bucket().gen_base_path();

src/Lib/Makefile.am

@@ -1,6 +1,7 @@
 SUBDIRS = \
 	Array \
 	DEM \
+	e00 \
 	Geometry \
         landcover \
 	Optimize \

src/Lib/Polygon/names.cxx

@@ -70,6 +70,8 @@ inline static void init ()
   set_area("Reservoir", ReservoirArea);
   set_area("Reservoir   Intermittent", IntReservoirArea);
   set_area("IntermittentReservoir", IntReservoirArea);
+  set_area("Road", RoadArea);
+  set_area("Railroad", RailroadArea);
   set_area("Stream", StreamArea);
   set_area("Canal", CanalArea);
   set_area("Glacier", GlacierArea);

src/Lib/Polygon/names.hxx

@@ -44,6 +44,8 @@ enum AreaType {
     IntLakeArea,
     ReservoirArea,
     IntReservoirArea,
+    RoadArea,
+    RailroadArea,
     StreamArea,
     CanalArea,
     GlacierArea,

src/Lib/Polygon/polygon.cxx

@@ -533,3 +533,20 @@ FGPolygon polygon_to_tristrip_old( const FGPolygon& in_poly ) {
     return result;
 }
 #endif
+
+
+// Send a polygon to standard output.
+ostream &
+operator<< (ostream &output, const FGPolygon &poly)
+{
+    int nContours = poly.contours();
+    output << nContours << endl;
+    for (int i = 0; i < nContours; i++) {
+	int nPoints = poly.contour_size(i);
+	output << nPoints << endl;
+	output << poly.get_hole_flag(i) << endl;
+	for (int j = 0; j < nPoints; j++) {
+	    output << poly.get_pt(i, j) << endl;
+	}
+    }
+}

src/Lib/Polygon/polygon.hxx

@@ -33,9 +33,11 @@
 #include <simgear/compiler.h>
 #include <simgear/math/sg_types.hxx>
 
+#include <iostream>
 #include <string>
 #include <vector>
 
+FG_USING_STD(ostream);
 FG_USING_STD(string);
 FG_USING_STD(vector);
 
@@ -139,6 +141,13 @@ public:
     inline void set_hole_flag( const int contour, const int flag ) {
 	hole_list[contour] = flag;
     }
+    inline bool has_holes () const {
+        for (int i = 0; i < contours(); i++) {
+	    if (get_hole_flag(i))
+	        return true;
+	}
+	return false;
+    }
 
     // shift every point in the polygon by lon, lat
     void shift( double lon, double lat );
@@ -200,6 +209,9 @@ FGPolygon polygon_xor( const FGPolygon& subject, const FGPolygon& clip );
 // Union
 FGPolygon polygon_union( const FGPolygon& subject, const FGPolygon& clip );
 
+// Output
+ostream &operator<< (ostream &output, const FGPolygon &poly);
+
 
 #endif // _POLYGON_HXX
 

src/Lib/TriangleJRS/triangle.c

@@ -303,6 +303,7 @@
 #define ONETHIRD 0.333333333333333333333333333333333333333333333333333333333333
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <math.h>
 #ifndef NO_TIMER
@@ -2728,7 +2729,7 @@ char **argv;
               k++;
             }
             workstring[k] = '\0';
-            minangle = (REAL) strtod(workstring, (char **) NULL);
+            minangle = (REAL) atof(workstring);
 	  } else {
             minangle = 20.0;
 	  }

src/Prep/Makefile.am

@@ -2,6 +2,7 @@ SUBDIRS = \
 	DemChop \
 	DemInfo \
 	DemRaw2ascii \
+	E00Lines \
 	GenAirports \
 	GSHHS \
 	MergerClipper \

src/Prep/MergerClipper/merger.hxx

@@ -43,7 +43,7 @@
 FG_USING_STD(string);
 FG_USING_STD(vector);
 
-#define FG_MAX_AREA_TYPES 40	// FIXME: also defined in clipper.hxx
+#define FG_MAX_AREA_TYPES 128	// FIXME: also defined in clipper.hxx
 
 class FGPolyList {
 public: