diff --git a/src/Lib/Geometry/util.cxx b/src/Lib/Geometry/util.cxx
index 6b5b36b7..376b59eb 100644
--- a/src/Lib/Geometry/util.cxx
+++ b/src/Lib/Geometry/util.cxx
@@ -414,6 +414,95 @@ Point3D midpoint( Point3D p0, Point3D p1 )
     return Point3D( (p0.x() + p1.x()) / 2, (p0.y() + p1.y()) / 2, (p0.z() + p1.z()) / 2 );
 }
 
+void
+makePolygons (const Line &line, double width, poly_list& polys)
+{
+    int nPoints = line.getPointCount();
+    int i;
+    int turn_dir;
+
+    Point3D cur_inner;
+    Point3D cur_outer;
+    Point3D prev_inner = Point3D(0.0f, 0.0f, 0.0f);
+    Point3D prev_outer = Point3D(0.0f, 0.0f, 0.0f);
+
+    double heading = 0.0f;
+    double az2 = 0.0f;
+    double dist = 0.0f;
+    double pt_x = 0.0f;
+    double pt_y = 0.0f;
+
+    TGPolygon   poly;
+
+    // generate poly and texparam lists for each line segment
+    for (i=0; i<nPoints; i++)
+    {
+        turn_dir = 0;
+
+        SG_LOG(SG_GENERAL, SG_DEBUG, "makePolygonsTP: calculating offsets for segment " << i);
+
+        // for each point on the PointsList, generate a quad from
+        // start to next, offset by 1/2 width from the edge
+        if (i == 0)
+        {
+            // first point on the list - offset heading is 90deg 
+            cur_outer = OffsetPointFirst( line.getPoint(i), line.getPoint(i+1), -width/2.0f );
+            cur_inner = OffsetPointFirst( line.getPoint(i), line.getPoint(i+1),  width/2.0f );
+        }
+        else if (i == nPoints-1)
+        {
+            // last point on the list - offset heading is 90deg 
+            cur_outer = OffsetPointLast( line.getPoint(i-1), line.getPoint(i), -width/2.0f );
+            cur_inner = OffsetPointLast( line.getPoint(i-1), line.getPoint(i),  width/2.0f );
+        }
+        else
+        {
+            // middle section
+            cur_outer = OffsetPointMiddle( line.getPoint(i-1), line.getPoint(i), line.getPoint(i+1), -width/2.0f, turn_dir );
+            cur_inner = OffsetPointMiddle( line.getPoint(i-1), line.getPoint(i), line.getPoint(i+1),  width/2.0f, turn_dir );
+        }
+
+        if ( (prev_inner.x() != 0.0f) && (prev_inner.y() != 0.0f) )
+        {
+            Point3D prev_mp = midpoint( prev_outer, prev_inner );
+            Point3D cur_mp  = midpoint( cur_outer,  cur_inner  );
+            geo_inverse_wgs_84( prev_mp.y(), prev_mp.x(), cur_mp.y(), cur_mp.x(), &heading, &az2, &dist);
+
+            poly.erase();
+
+            poly.add_node( 0, prev_inner );
+            poly.add_node( 0, prev_outer );
+
+            // we need to extend one of the points so we're sure we don't create adjacent edges
+            if (turn_dir == 0)
+            {
+                // turned right - offset outer
+                geo_inverse_wgs_84( prev_outer.y(), prev_outer.x(), cur_outer.y(), cur_outer.x(), &heading, &az2, &dist);
+                geo_direct_wgs_84( cur_outer.y(), cur_outer.x(), heading, MP_STRETCH, &pt_y, &pt_x, &az2 );
+
+                poly.add_node( 0, Point3D( pt_x, pt_y, 0.0f) );
+                //poly.add_node( 0, cur_outer );
+                poly.add_node( 0, cur_inner );
+            }
+            else
+            {
+                // turned left - offset inner
+                geo_inverse_wgs_84( prev_inner.y(), prev_inner.x(), cur_inner.y(), cur_inner.x(), &heading, &az2, &dist);
+                geo_direct_wgs_84( cur_inner.y(), cur_inner.x(), heading, MP_STRETCH, &pt_y, &pt_x, &az2 );
+
+                poly.add_node( 0, cur_outer );
+                poly.add_node( 0, Point3D( pt_x, pt_y, 0.0f) );
+                //poly.add_node( 0, cur_inner );
+            }
+
+            polys.push_back(poly);
+        }
+
+        prev_outer = cur_outer;
+        prev_inner = cur_inner;
+    }
+}
+
 void
 makePolygonsTP (const Line &line, double width, poly_list& polys, texparams_list &tps)
 {
diff --git a/src/Lib/Geometry/util.hxx b/src/Lib/Geometry/util.hxx
index 6b219f8c..22ba6df0 100644
--- a/src/Lib/Geometry/util.hxx
+++ b/src/Lib/Geometry/util.hxx
@@ -93,6 +93,7 @@ void makePolygon (const Point3D &p, double width, TGPolygon &polygon);
  */
 void makePolygon (const Line &line, double width, TGPolygon &polygon);
 
+void makePolygons   (const Line &line, double width, poly_list &segments);
 void makePolygonsTP (const Line &line, double width, poly_list &segments, texparams_list &tps);
 
 /**
diff --git a/src/Lib/Polygon/chop-bin.cxx b/src/Lib/Polygon/chop-bin.cxx
index c9c0180c..7c67f6bb 100644
--- a/src/Lib/Polygon/chop-bin.cxx
+++ b/src/Lib/Polygon/chop-bin.cxx
@@ -153,6 +153,132 @@ static void clip_and_write_poly( string root, long int p_index,
     }
 }
 
+static void clip_and_write_polys_with_mask( string root, long int p_index,
+                                            const string &poly_type,
+                                            SGBucket b, const poly_list& segments,
+                                            bool preserve3d )
+{
+    Point3D c, min, max, p;
+
+    c = Point3D( b.get_center_lon(), b.get_center_lat(), 0 );
+    double span = b.get_width();
+    TGPolygon base, result;
+    char tile_name[256], poly_index[256];
+
+    // calculate bucket dimensions
+    if ( (c.y() >= -89.0) && (c.y() < 89.0) ) {
+        min.setx( c.x() - span / 2.0 );
+        max.setx( c.x() + span / 2.0 );
+        min.sety( c.y() - SG_HALF_BUCKET_SPAN );
+        max.sety( c.y() + SG_HALF_BUCKET_SPAN );
+    } else if ( c.y() < -89.0) {
+        min.setx( -90.0 );
+        max.setx( -89.0 );
+        min.sety( -180.0 );
+        max.sety( 180.0 );
+    } else if ( c.y() >= 89.0) {
+        min.setx( 89.0 );
+        max.setx( 90.0 );
+        min.sety( -180.0 );
+        max.sety( 180.0 );
+    } else {
+        SG_LOG( SG_GENERAL, SG_ALERT,
+                "Out of range latitude in clip_and_write_poly() = " << c.y() );
+    }
+
+    min.setz( 0.0 );
+    max.setz( 0.0 );
+
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  (" << min << ") (" << max << ")" );
+
+    // set up clipping tile
+    base.add_node( 0, Point3D(min.x(), min.y(), 0) );
+    base.add_node( 0, Point3D(max.x(), min.y(), 0) );
+    base.add_node( 0, Point3D(max.x(), max.y(), 0) );
+    base.add_node( 0, Point3D(min.x(), max.y(), 0) );
+
+    // SG_LOG( SG_GENERAL, SG_DEBUG, "base = 4 vertices" );
+
+    /*
+       FILE *bfp= fopen("base", "w");
+       gpc_write_polygon(bfp, &base);
+       fclose(bfp);
+     */
+
+    poly_list    clipped_shapes;
+    TGPolygon    shape;
+    unsigned int s;
+
+    for ( s = 0; s < segments.size(); s++ ) {
+        shape = segments[s];
+
+        // SG_LOG(SG_GENERAL, SG_DEBUG, "shape contours = " << shape.contours() );
+        // for ( int ii = 0; ii < shape.contours(); ii++ )
+        //    SG_LOG(SG_GENERAL, SG_DEBUG, "   hole = " << shape.get_hole_flag(ii) );
+
+        result = tgPolygonInt( base, shape );
+
+        // write_polygon(shape, "shape");
+        // write_polygon(result, "result");
+
+        // SG_LOG(SG_GENERAL, SG_DEBUG, "result contours = " << result.contours() );
+        // for ( int ii = 0; ii < result.contours(); ii++ ) {
+        //     SG_LOG(SG_GENERAL, SG_DEBUG, "  hole = " << result.get_hole_flag(ii) );
+        // }
+
+        if ( preserve3d )
+            result.inherit_elevations( shape );
+
+        if ( result.contours() > 0 ) {
+            clipped_shapes.push_back( result );
+        }
+    }
+
+    // Now we can write the file
+    long int t_index = b.gen_index();
+    string path = root + "/" + b.gen_base_path();
+
+    SGPath sgp( path );
+    sgp.append( "dummy" );
+    sgp.create_dir( 0755 );
+
+    sprintf( tile_name, "%ld", t_index );
+    string polyfile = path + "/" + tile_name;
+
+    sprintf( poly_index, "%ld", p_index );
+    polyfile += ".";
+    polyfile += poly_index;
+
+    FILE *rfp = fopen( polyfile.c_str(), "w" );
+
+    if ( preserve3d )
+        fprintf( rfp, "#3D_WITH_MASK\n" );
+    else
+        fprintf( rfp, "#2D_WITH_MASK\n" );
+    fprintf( rfp, "%s\n", poly_type.c_str() );
+
+    fprintf( rfp, "%d\n", (int)clipped_shapes.size() );
+    
+    for (s=0; s<clipped_shapes.size(); s++) {
+        result = clipped_shapes[s];
+    
+        fprintf( rfp, "%d\n", result.contours() );
+        for ( int i = 0; i < result.contours(); ++i ) {
+            fprintf( rfp, "%d\n", result.contour_size(i) );
+            fprintf( rfp, "%d\n", result.get_hole_flag(i) );
+            for ( int j = 0; j < result.contour_size(i); ++j ) {
+                p = result.get_pt( i, j );
+                if ( preserve3d )
+                    fprintf( rfp, "%.15f  %.15f %.15f\n", p.x(), p.y(), p.z() );
+                else
+                    fprintf( rfp, "%.15f  %.15f\n", p.x(), p.y() );
+            }
+        }
+    }
+
+    fclose( rfp );
+}
+
 static void clip_and_write_poly_tp( string root, long int p_index,
                                     const string &poly_type,
                                     SGBucket b, const TGPolygon& shape,
@@ -401,6 +527,164 @@ void tgChopNormalPolygon( const string& path, const string& poly_type,
     }
 }
 
+void tgChopNormalPolygonsWithMask(const std::string& path, const std::string& poly_type, 
+                                  const poly_list& segments, bool preserve3d )
+{
+    Point3D min, max, p;
+    TGPolygon shape;
+    long int index;
+    int i, j;
+    unsigned int s;
+
+    // bail out immediately if poly_list is empty
+    if ( segments.size() == 0 )
+        return;
+
+    // get next polygon index
+    index = poly_index_next();
+
+    min = Point3D(  200.0 );
+    max = Point3D( -200.0 );
+
+    for ( s = 0; s < segments.size(); s++) {
+        shape = segments[s];
+
+        // find min/max of polygon
+        for ( i = 0; i < shape.contours(); i++ ) {
+            for ( j = 0; j < shape.contour_size(i); j++ ) {
+                p = shape.get_pt( i, j );
+
+                if ( p.x() < min.x() ) min.setx( p.x() ); if ( p.y() < min.y() ) min.sety( p.y() ); if ( p.x() > max.x() ) max.setx( p.x() ); if ( p.y() > max.y() ) max.sety( p.y() );
+            }
+        }
+    }
+
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  min = " << min << " max = " << max );
+
+    // find buckets for min, and max points of convex hull.
+    // note to self: self, you should think about checking for
+    // polygons that span the date line
+    SGBucket b_min( min.x(), min.y() );
+    SGBucket b_max( max.x(), max.y() );
+
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  Bucket min = " << b_min );
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  Bucket max = " << b_max );
+
+    if ( b_min == b_max ) {
+        // shape entirely contained in a single bucket, write and bail
+        clip_and_write_polys_with_mask( path, index, poly_type, b_min, segments, preserve3d );
+        return;
+    }
+
+    SGBucket b_cur;
+    int dx, dy;
+
+    sgBucketDiff(b_min, b_max, &dx, &dy);
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  polygon spans tile boundaries" );
+    SG_LOG( SG_GENERAL, SG_DEBUG, "  dx = " << dx << "  dy = " << dy );
+
+    if ( (dx > 2880) || (dy > 1440) )
+        throw sg_exception("something is really wrong in split_polygon()!!!!");
+
+    if ( dy <= 1 ) {
+        // we are down to at most two rows, write each column and then bail
+        double min_center_lat = b_min.get_center_lat();
+        double min_center_lon = b_min.get_center_lon();
+        for ( j = 0; j <= dy; ++j ) {
+            for ( i = 0; i <= dx; ++i ) {
+                b_cur = sgBucketOffset(min_center_lon, min_center_lat, i, j);
+                clip_and_write_polys_with_mask( path, index, poly_type, b_cur, segments, preserve3d );
+            }
+        }
+        return;
+    }
+
+    // we have two or more rows left, split in half (along a
+    // horizontal dividing line) and recurse with each half
+
+    // find mid point (integer math)
+    int mid = (dy + 1) / 2 - 1;
+
+    // determine horizontal clip line
+    SGBucket b_clip = sgBucketOffset(min.x(), min.y(), 0, mid);
+    double clip_line = b_clip.get_center_lat();
+    if ( (clip_line >= -90.0 + SG_HALF_BUCKET_SPAN)
+         && (clip_line < 90.0 - SG_HALF_BUCKET_SPAN) )
+        clip_line += SG_HALF_BUCKET_SPAN;
+    else if ( clip_line < -89.0 )
+        clip_line = -89.0;
+    else if ( clip_line >= 89.0 )
+        clip_line = 90.0;
+    else {
+        SG_LOG( SG_GENERAL, SG_ALERT,
+                "Out of range latitude in clip_and_write_poly() = "
+                << clip_line );
+    }
+
+    {
+        //
+        // Crop bottom area (hopefully by putting this in it's own
+        // scope we can shorten the life of some really large data
+        // structures to reduce memory use)
+        //
+        SG_LOG( SG_GENERAL, SG_DEBUG,
+                "Generating bottom half (" << min.y() << "-" <<
+                clip_line << ")" );
+
+        TGPolygon bottom, bottom_clip;
+        poly_list bottom_clip_list;
+
+        bottom.erase();
+        bottom.add_node( 0, Point3D(-180.0, min.y(), 0) );
+        bottom.add_node( 0, Point3D(180.0, min.y(), 0) );
+        bottom.add_node( 0, Point3D(180.0, clip_line, 0) );
+        bottom.add_node( 0, Point3D(-180.0, clip_line, 0) );
+
+        for (s=0; s<segments.size(); s++) {            
+            bottom_clip.erase();
+            bottom_clip = tgPolygonInt( bottom, segments[s] );
+
+            if ( bottom_clip.contours() > 0 ) {
+                bottom_clip_list.push_back( bottom_clip );
+            }
+        }
+
+        tgChopNormalPolygonsWithMask( path, poly_type, bottom_clip_list, preserve3d );
+    }
+
+    {
+        //
+        // Crop top area (hopefully by putting this in it's own scope
+        // we can shorten the life of some really large data
+        // structures to reduce memory use)
+        //
+
+        SG_LOG( SG_GENERAL, SG_DEBUG,
+                "Generating top half (" << clip_line << "-" <<
+                max.y() << ")" );
+
+        TGPolygon top, top_clip;
+        poly_list top_clip_list;
+
+        top.erase();
+        top.add_node( 0, Point3D(-180.0, clip_line, 0) );
+        top.add_node( 0, Point3D(180.0, clip_line, 0) );
+        top.add_node( 0, Point3D(180.0, max.y(), 0) );
+        top.add_node( 0, Point3D(-180.0, max.y(), 0) );
+
+        for (s=0; s<segments.size(); s++) {            
+            top_clip.erase();
+            top_clip = tgPolygonInt( top, segments[s] );
+
+            if ( top_clip.contours() > 0 ) {
+                top_clip_list.push_back( top_clip );
+            }
+        }
+
+        tgChopNormalPolygonsWithMask( path, poly_type, top_clip_list, preserve3d );
+    }
+}
+
 // process polygon shape (chop up along tile boundaries and write each
 // polygon piece to a file)
 void tgChopNormalPolygonTP( const string& path, const string& poly_type,
diff --git a/src/Lib/Polygon/chop.hxx b/src/Lib/Polygon/chop.hxx
index 3ea2c382..a10e6bd3 100644
--- a/src/Lib/Polygon/chop.hxx
+++ b/src/Lib/Polygon/chop.hxx
@@ -37,6 +37,9 @@
 void tgChopNormalPolygon( const std::string& path, const std::string& poly_type,
                           const TGPolygon& shape, bool preserve3d );
 
+void tgChopNormalPolygonsWithMask(const std::string& path, const std::string& poly_type, 
+                          const poly_list& segments, bool preserve3d );
+
 // process polygon shape (chop up along tile boundaries and write each
 // polygon piece to a file)
 void tgChopNormalPolygonTP( const std::string& path, const std::string& poly_type,
diff --git a/src/Prep/OGRDecode/ogr-decode.cxx b/src/Prep/OGRDecode/ogr-decode.cxx
index 2a0316f9..28c5775d 100644
--- a/src/Prep/OGRDecode/ogr-decode.cxx
+++ b/src/Prep/OGRDecode/ogr-decode.cxx
@@ -110,6 +110,83 @@ void processLineString(OGRLineString* poGeometry,
     tgChopNormalPolygon(work_dir, area_type, shape, false);
 }
 
+void processLineStringWithMask(OGRLineString* poGeometry,
+                               const string& work_dir,
+                               const string& area_type,
+                               int width)
+{
+    poly_list segments;
+    TGPolygon segment;
+    tg::Line line;
+    Point3D p0, p1;
+    double heading, dist, az2;
+    double pt_x = 0.0f, pt_y = 0.0f;
+    int i, j, numPoints, numSegs;
+    double max_dist;
+
+    numPoints = poGeometry->getNumPoints();
+    if (numPoints < 2) {
+        SG_LOG( SG_GENERAL, SG_WARN, "Skipping line with less than two points" );
+        return;
+    }
+
+    max_dist = (double)width * 10.0f;
+
+    // because vector data can generate adjacent polys, lets stretch the two enpoints by a little bit
+    p0 = Point3D(poGeometry->getX(0),poGeometry->getY(0),0);
+    p1 = Point3D(poGeometry->getX(1),poGeometry->getY(1),0);
+
+    geo_inverse_wgs_84( p1.y(), p1.x(), p0.y(), p0.x(), &heading, &az2, &dist);
+    geo_direct_wgs_84( p0.y(), p0.x(), heading, EP_STRETCH, &pt_y, &pt_x, &az2 );
+    line.addPoint( Point3D( pt_x, pt_y, 0.0f ) );
+
+    // now add the middle points : if they are too far apart, add intermediate nodes
+    for ( i=1;i<numPoints-1;i++) {
+        p0 = Point3D(poGeometry->getX(i-1),poGeometry->getY(i-1),0);
+        p1 = Point3D(poGeometry->getX(i  ),poGeometry->getY(i  ),0);
+        geo_inverse_wgs_84( p0.y(), p0.x(), p1.y(), p1.x(), &heading, &az2, &dist);
+
+        if (dist > max_dist)
+        {
+            numSegs = (dist / max_dist) + 1;
+            dist = dist / (double)numSegs;
+
+            for (j=0; j<numSegs; j++)
+            {
+                geo_direct_wgs_84( p0.y(), p0.x(), heading, dist*(j+1), &pt_y, &pt_x, &az2 );
+                line.addPoint( Point3D( pt_x, pt_y, 0.0f ) );
+            }        
+        }
+        else
+        {
+            line.addPoint(p1);
+        }
+    }
+
+    // then stretch the last point
+    // because vector data can generate adjacent polys, lets stretch the two enpoints by a little bit
+    p0 = Point3D(poGeometry->getX(numPoints-2),poGeometry->getY(numPoints-2),0);
+    p1 = Point3D(poGeometry->getX(numPoints-1),poGeometry->getY(numPoints-1),0);
+
+    geo_inverse_wgs_84( p0.y(), p0.x(), p1.y(), p1.x(), &heading, &az2, &dist);
+    geo_direct_wgs_84( p1.y(), p1.x(), heading, EP_STRETCH, &pt_y, &pt_x, &az2 );
+    line.addPoint( Point3D( pt_x, pt_y, 0.0f ) );
+
+    // make a plygons from the line segments
+    tg::makePolygons(line,width,segments);
+
+#if 1
+    for ( i = 0; i < (int)segments.size(); ++i ) {
+    	segment = segments[i];
+
+        tgChopNormalPolygon(work_dir, area_type, segment, false);
+    }
+#else
+    tgChopNormalPolygonsWithMask(work_dir, area_type, segments, false);
+#endif
+
+}
+
 void processLineStringWithTextureInfo(OGRLineString* poGeometry,
                                       const string& work_dir,
                                       const string& area_type,
@@ -406,7 +483,7 @@ void processLayer(OGRLayer* poLayer,
             if (texture_lines) {
                 processLineStringWithTextureInfo((OGRLineString*)poGeometry,work_dir,area_type_name,width);
             } else {
-                processLineString((OGRLineString*)poGeometry,work_dir,area_type_name,width);
+                processLineStringWithMask((OGRLineString*)poGeometry,work_dir,area_type_name,width);
             }
             break;
         }
@@ -421,7 +498,7 @@ void processLayer(OGRLayer* poLayer,
                 if (texture_lines) {
                     processLineStringWithTextureInfo((OGRLineString*)poGeometry,work_dir,area_type_name,width);
                 } else {
-                    processLineString((OGRLineString*)poGeometry,work_dir,area_type_name,width);
+                    processLineStringWithMask((OGRLineString*)poGeometry,work_dir,area_type_name,width);
                 }
             }
             break;