diff --git a/Scenery/material.cxx b/Scenery/material.cxx
index 8b27b037b..abbd6ed72 100644
--- a/Scenery/material.cxx
+++ b/Scenery/material.cxx
@@ -172,8 +172,6 @@ int fgMATERIAL_MGR::load_lib ( void ) {
 			      /* GL_LINEAR */ 
 			      /* GL_NEAREST_MIPMAP_LINEAR */
 			      GL_LINEAR_MIPMAP_LINEAR ) ;
-	    xglTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ) ;
-	    xglHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST ) ;
 
 	    /* load in the texture data */
 	    tpath[0] = '\0';
@@ -301,6 +299,12 @@ fgMATERIAL_MGR::~fgMATERIAL_MGR ( void ) {
 
 
 // $Log$
+// Revision 1.8  1998/07/08 14:47:20  curt
+// Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
+// polare3d.h renamed to polar3d.hxx
+// fg{Cartesian,Polar}Point3d consolodated.
+// Added some initial support for calculating local current ground elevation.
+//
 // Revision 1.7  1998/07/04 00:54:28  curt
 // Added automatic mipmap generation.
 //
diff --git a/Scenery/obj.cxx b/Scenery/obj.cxx
index a37877942..bcb81893b 100644
--- a/Scenery/obj.cxx
+++ b/Scenery/obj.cxx
@@ -52,7 +52,7 @@ using namespace std;
 #include <Main/options.hxx>
 #include <Math/mat3.h>
 #include <Math/fg_random.h>
-#include <Math/polar3d.h>
+#include <Math/polar3d.hxx>
 
 #include "material.hxx"
 #include "obj.hxx"
@@ -88,9 +88,9 @@ static void calc_normal(double p1[3], double p2[3],
 
 
 // Calculate texture coordinates for a given point.
-fgPolarPoint3d calc_tex_coords(double *node, fgCartesianPoint3d *ref) {
-    fgCartesianPoint3d cp;
-    fgPolarPoint3d pp;
+fgPoint3d calc_tex_coords(double *node, fgPoint3d *ref) {
+    fgPoint3d cp;
+    fgPoint3d pp;
 
     cp.x = node[0] + ref->x; 
     cp.y = node[1] + ref->y;
@@ -109,7 +109,7 @@ fgPolarPoint3d calc_tex_coords(double *node, fgCartesianPoint3d *ref) {
 int fgObjLoad(char *path, fgTILE *tile) {
     fgOPTIONS *o;
     fgFRAGMENT fragment;
-    fgPolarPoint3d pp;
+    fgPoint3d pp;
     char fgpath[256], line[256], material[256];
     double approx_normal[3], normal[3], scale;
     // double x, y, z, xmax, xmin, ymax, ymin, zmax, zmin;
@@ -441,6 +441,12 @@ int fgObjLoad(char *path, fgTILE *tile) {
 
 
 // $Log$
+// Revision 1.17  1998/07/08 14:47:21  curt
+// Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
+// polare3d.h renamed to polar3d.hxx
+// fg{Cartesian,Polar}Point3d consolodated.
+// Added some initial support for calculating local current ground elevation.
+//
 // Revision 1.16  1998/07/06 21:34:33  curt
 // Added using namespace std for compilers that support this.
 //
diff --git a/Scenery/scenery.hxx b/Scenery/scenery.hxx
index 9ac533818..47777580d 100644
--- a/Scenery/scenery.hxx
+++ b/Scenery/scenery.hxx
@@ -42,10 +42,10 @@ struct fgSCENERY {
     int terrain_skip;
 
     /* center of current scenery chunk */
-    fgCartesianPoint3d center;
+    fgPoint3d center;
 
     /* next center of current scenery chunk */
-    fgCartesianPoint3d next_center;
+    fgPoint3d next_center;
 
     /* angle of sun relative to current local horizontal */
     double sun_angle;
@@ -71,9 +71,15 @@ void fgSceneryRender( void );
 
 
 /* $Log$
-/* Revision 1.2  1998/05/02 01:52:16  curt
-/* Playing around with texture coordinates.
+/* Revision 1.3  1998/07/08 14:47:22  curt
+/* Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
+/* polare3d.h renamed to polar3d.hxx
+/* fg{Cartesian,Polar}Point3d consolodated.
+/* Added some initial support for calculating local current ground elevation.
 /*
+ * Revision 1.2  1998/05/02 01:52:16  curt
+ * Playing around with texture coordinates.
+ *
  * Revision 1.1  1998/04/30 12:35:31  curt
  * Added a command line rendering option specify smooth/flat shading.
  *
diff --git a/Scenery/tile.hxx b/Scenery/tile.hxx
index ce31cd410..e79a8dc82 100644
--- a/Scenery/tile.hxx
+++ b/Scenery/tile.hxx
@@ -60,7 +60,7 @@ class fgFRAGMENT {
 
 public:
     // culling data for this object fragment (fine grain culling)
-    fgCartesianPoint3d center;
+    fgPoint3d center;
     double bounding_radius;
 
     // variable offset data for this object fragment for this frame
@@ -96,9 +96,9 @@ class fgTILE {
 public:
 
     // culling data for whole tile (course grain culling)
-    fgCartesianPoint3d center;
+    fgPoint3d center;
     double bounding_radius;
-    fgCartesianPoint3d offset;
+    fgPoint3d offset;
     GLdouble model_view[16];
 
     // this tile's official location in the world
@@ -121,6 +121,12 @@ public:
 
 
 // $Log$
+// Revision 1.10  1998/07/08 14:47:22  curt
+// Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
+// polare3d.h renamed to polar3d.hxx
+// fg{Cartesian,Polar}Point3d consolodated.
+// Added some initial support for calculating local current ground elevation.
+//
 // Revision 1.9  1998/07/06 21:34:34  curt
 // Added using namespace std for compilers that support this.
 //
diff --git a/Scenery/tilemgr.cxx b/Scenery/tilemgr.cxx
index fa7e16c10..d4b5f85f0 100644
--- a/Scenery/tilemgr.cxx
+++ b/Scenery/tilemgr.cxx
@@ -41,7 +41,10 @@
 #include <Include/fg_types.h>
 #include <Main/options.hxx>
 #include <Main/views.hxx>
+#include <Math/fg_geodesy.h>
 #include <Math/mat3.h>
+#include <Math/polar3d.hxx>
+#include <Math/vector.hxx>
 
 #include "material.hxx"
 #include "obj.hxx"
@@ -210,8 +213,24 @@ int fgTileMgrUpdate( void ) {
 }
 
 
+// Calculate shortest distance from point to line
+static double point_line_dist( fgPoint3d *tc, fgPoint3d *vp, MAT3vec d) {
+    MAT3vec p, p0;
+    double dist;
+
+    p[0] = tc->x; p[1] = tc->y; p[2] = tc->z;
+    p0[0] = vp->x; p0[1] = vp->y; p0[2] = vp->z;
+
+    dist = fgPointLine(p, p0, d);
+
+    // printf("dist = %.2f\n", dist);
+
+    return(dist);
+}
+
+
 // Calculate if point/radius is inside view frustum
-static int viewable( fgCartesianPoint3d *cp, double radius ) {
+static int viewable( fgPoint3d *cp, double radius ) {
     fgVIEW *v;
     MAT3hvec world, eye;
     int viewable = 1; // start by assuming it's viewable
@@ -300,11 +319,12 @@ void fgTileMgrRender( void ) {
     fgTILE *t;
     fgVIEW *v;
     fgBUCKET p;
-    fgCartesianPoint3d frag_offset;
+    fgPoint3d frag_offset, fc, pp;
     fgFRAGMENT *frag_ptr;
     fgMATERIAL *mtl_ptr;
     fgTILE *last_tile_ptr;
     GLdouble *m;
+    double dist, min_dist, lat_geod, alt, sea_level_r;
     double x, y, z;
     list < fgFRAGMENT > :: iterator current;
     list < fgFRAGMENT > :: iterator last;
@@ -330,6 +350,7 @@ void fgTileMgrRender( void ) {
 
     // initialize the transient per-material fragment lists
     material_mgr.init_transient_material_lists();
+    min_dist = 100000.0;
 
     // Pass 1
     // traverse the potentially viewable tile list
@@ -354,6 +375,38 @@ void fgTileMgrRender( void ) {
 	m[14] = m[2] * x + m[6] * y + m[10] * z + m[14];
 	m[15] = m[3] * x + m[7] * y + m[11] * z + m[15];
 
+	// temp ... calc current terrain elevation
+	// calculate distance from vertical tangent line at
+	// current position to center of tile.
+	dist = point_line_dist(&(t->offset), &(v->view_pos), v->local_up);
+	if ( dist < t->bounding_radius ) {
+
+	    // traverse fragment list for tile
+	    current = t->fragment_list.begin();
+	    last = t->fragment_list.end();
+
+	    while ( current != last ) {
+		frag_ptr = &(*current);
+		current++;
+		dist = point_line_dist( &(frag_ptr->center), &(v->view_pos), 
+					v->local_up);
+		if ( dist <= frag_ptr->bounding_radius ) {
+		    if ( dist < min_dist ) {
+			min_dist = dist;
+			// compute geocentric coordinates of tile center
+			pp = fgCartToPolar3d(frag_ptr->center);
+			// convert to geodetic coordinates
+			fgGeocToGeod(pp.lat, pp.radius, &lat_geod, 
+				     &alt, &sea_level_r);
+		    }
+		}
+	    }
+
+	    if ( min_dist <= t->bounding_radius ) {
+		printf("min_dist = %.2f  alt = %.2f\n", min_dist, alt);
+	    }
+	}
+
 	// Course (tile based) culling
 	if ( viewable(&(t->offset), t->bounding_radius) ) {
 	    // at least a portion of this tile could be viewable
@@ -478,6 +531,12 @@ void fgTileMgrRender( void ) {
 
 
 // $Log$
+// Revision 1.23  1998/07/08 14:47:23  curt
+// Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
+// polare3d.h renamed to polar3d.hxx
+// fg{Cartesian,Polar}Point3d consolodated.
+// Added some initial support for calculating local current ground elevation.
+//
 // Revision 1.22  1998/07/04 00:54:31  curt
 // Added automatic mipmap generation.
 //