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- Test a different approach for assigning land cover attributes to "default'

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cover" areas.  Rather than artificially cut in polygon areas, just lookup
  a land cover type for unassigned triangles.  I think this has potential, but
  it needs more work to eliminate some odd artifacts.

- Revove --min-angle= option.

- Don't re-fit() triangle array to try to achieve a particular range of
  node quantities ... this is all pre-computed with a much smarter, much
  more efficient algorithm.
This commit is contained in:
curt 2003-08-19 02:35:35 +00:00
parent f5f961b8c0
commit 730c454320
1 changed files with 66 additions and 95 deletions
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161
src/BuildTiles/Main/main.cxx
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@ -243,24 +243,23 @@ static AreaType get_area_type (const LandCover &cover,
int cover_value = cover.getValue(xpos, ypos);
AreaType area = translateUSGSCover(cover_value);
// Non-default area is fine.
if (area != DefaultArea) {
return area;
}
// If we're stuck with the default area,
// try to borrow from a neighbour.
else {
for (double x = xpos - dx; x <= xpos + dx; x += dx) {
for (double y = ypos - dy; y < ypos + dx; y += dy) {
if (x != xpos || y != ypos) {
cover_value = cover.getValue(x, y);
area = translateUSGSCover(cover_value);
if (area != DefaultArea)
return area;
}
}
}
// Non-default area is fine.
return area;
} else {
// If we're stuck with the default area, try to borrow from a
// neighbour.
for (double x = xpos - dx; x <= xpos + dx; x += dx) {
for (double y = ypos - dy; y < ypos + dx; y += dy) {
if (x != xpos || y != ypos) {
cover_value = cover.getValue(x, y);
area = translateUSGSCover(cover_value);
if (area != DefaultArea) {
return area;
}
}
}
}
}
// OK, give up and return default
@ -288,7 +287,7 @@ static void make_area( const LandCover &cover, TGPolygon *polys,
}
// Generate polygons from la and-cover raster. Horizontally- or
// Generate polygons from land-cover raster. Horizontally- or
// vertically-adjacent polygons will be merged automatically.
static int actual_load_landcover ( TGConstruct & c,
TGClipper &clipper ) {
@ -389,10 +388,15 @@ static int load_polys( TGConstruct& c ) {
cout << " loaded " << count << " total polys" << endl;
}
// now we are trying an idea of taking all unassigned land mass
// polygons (i.e. default cover type) and assigning them to the
// nearest cover type
#if 0
// Load the land use polygons if the --cover option was specified
if ( c.get_cover().size() > 0 ) {
count += actual_load_landcover (c, clipper);
}
#endif
point2d min, max;
min.x = c.get_bucket().get_center_lon() - 0.5 * c.get_bucket().get_width();
@ -434,6 +438,7 @@ static bool load_array( TGConstruct& c, TGArray& array) {
SGBucket b = c.get_bucket();
array.parse( b );
array.remove_voids();
return true;
}
@ -454,7 +459,7 @@ static void first_triangulate( TGConstruct& c, const TGArray& array,
cout << "done building node list and polygons" << endl;
cout << "ready to do triangulation" << endl;
t.run_triangulate( c.get_angle(), 1 );
t.run_triangulate( 0.0, 1 );
cout << "finished triangulation" << endl;
}
@ -470,7 +475,7 @@ static void second_triangulate( TGConstruct& c, TGTriangle& t ) {
cout << " (pre) nodes = " << c.get_tri_nodes().size() << endl;
cout << " (pre) normals = " << c.get_point_normals().size() << endl;
t.run_triangulate( c.get_angle(), 2 );
t.run_triangulate( 0.0, 2 );
cout << " (post) nodes = " << t.get_out_nodes().size() << endl;
@ -596,6 +601,39 @@ static void fix_point_heights( TGConstruct& c, const TGArray& array )
}
// For each triangle assigned to the "default" area type, see if we
// can lookup a better land cover type from the 1km data structure.
static void fix_land_cover_assignments( TGConstruct& c ) {
cout << "Fixing up default land cover types" << endl;
// the list of node locations
TGTriNodes trinodes = c.get_tri_nodes();
point_list geod_nodes = trinodes.get_node_list();
// the list of triangles (with area type attribute)
triele_list tri_elements = c.get_tri_elements();
// traverse the triangle element groups
cout << " Total Nodes = " << geod_nodes.size() << endl;
cout << " Total triangles = " << tri_elements.size() << endl;
for ( unsigned int i = 0; i < tri_elements.size(); ++i ) {
TGTriEle t = tri_elements[i];
if ( t.get_attribute() == DefaultArea ) {
Point3D average = ( geod_nodes[t.get_n1()]
+ geod_nodes[t.get_n2()]
+ geod_nodes[t.get_n3()] ) / 3.0;
cout << " average triangle center = " << average;
AreaType a = get_area_type ( c.get_cover(),
average.x(), average.y(),
1.0 / 120.0, 1.0 / 120.0 );
cout << " new attrib = " << get_area_name( a ) << endl;
// update the actual structure
c.set_tri_attribute( i, a );
}
}
}
// build the wgs-84 point list
static void build_wgs_84_point_list( TGConstruct& c, const TGArray& array ) {
point_list geod_nodes;
@ -867,13 +905,6 @@ static void construct_tile( TGConstruct& c ) {
// 80% of max nodes. We should really have the sim end handle
// arbitrarily complex tiles.
bool acceptable = false;
bool growing = false;
bool shrinking = false;
double error = 200.0;
int count = 0;
// load and clip 2d polygon data
if ( load_polys( c ) == 0 ) {
// don't build the tile if there is no 2d data ... it *must*
@ -887,69 +918,10 @@ static void construct_tile( TGConstruct& c ) {
TGTriangle t;
while ( ! acceptable ) {
// do a least squares fit of the (array) data with the given
// error tolerance
array.fit( error );
// triangulate the data for each polygon
first_triangulate( c, array, t );
// triangulate the data for each polygon
first_triangulate( c, array, t );
acceptable = true;
count = t.get_out_nodes_size();
if ( (count < c.get_min_nodes()) && (error >= 25.0) ) {
// reduce error tolerance until number of points exceeds the
// minimum threshold
cout << "produced too few nodes ..." << endl;
acceptable = false;
growing = true;
if ( shrinking ) {
error /= 1.25;
shrinking = false;
} else {
error /= 1.5;
}
cout << "Setting error to " << error << " and retrying fit."
<< endl;
}
if ( count > c.get_max_nodes() ) {
if ( error <= 1000.0 ) {
// increase error tolerance until number of points drops below
// the maximum threshold
cout << "produced too many nodes ..." << endl;
acceptable = false;
shrinking = true;
if ( growing ) {
error *= 1.25;
growing = false;
} else {
error *= 1.5;
}
cout << "Setting error to " << error << " and retrying fit."
<< endl;
} else {
// we tried, but can't seem to get down to a
// reasonable number of points even with a huge error
// tolerance. This could be related to the triangle()
// call which might be having trouble with our input
// set. Let's just die hope that our parent can try
// again with a smaller interior triangle angle.
cout << "Error: Too many nodes." << endl;
exit(-1);
}
}
}
cout << "finished fit with error = " << error << " node count = "
<< count << endl;
cout << "number of fitted nodes = " << t.get_out_nodes_size() << endl;
// save the results of the triangulation
c.set_tri_nodes( t.get_out_nodes() );
@ -1001,6 +973,11 @@ static void construct_tile( TGConstruct& c ) {
c.set_point_normals( normals );
}
// Now for all the remaining "default" land cover polygons, assign
// each one it's proper type from the land use/land cover
// database.
fix_land_cover_assignments( c );
// calculate wgs84 (cartesian) form of node list
build_wgs_84_point_list( c, array );
@ -1021,7 +998,6 @@ static void usage( const string name ) {
cout << "[ --output-dir=<directory>" << endl;
cout << " --work-dir=<directory>" << endl;
cout << " --cover=<path to land-cover raster>" << endl;
cout << " --min-angle=<angle>" << endl;
cout << " --tile-id=<id>" << endl;
cout << " --lon=<degrees>" << endl;
cout << " --lat=<degrees>" << endl;
@ -1036,7 +1012,6 @@ static void usage( const string name ) {
int main(int argc, char **argv) {
string output_dir = ".";
string work_dir = ".";
string min_angle = "10";
string cover = "";
double lon = -110.664244; // P13
double lat = 33.352890;
@ -1061,8 +1036,6 @@ int main(int argc, char **argv) {
output_dir = arg.substr(13);
} else if (arg.find("--work-dir=") == 0) {
work_dir = arg.substr(11);
} else if (arg.find("--min-angle=") == 0) {
min_angle = arg.substr(12);
} else if (arg.find("--tile-id=") == 0) {
tile_id = atol(arg.substr(10).c_str());
} else if (arg.find("--lon=") == 0) {
@ -1086,7 +1059,6 @@ int main(int argc, char **argv) {
cout << "Output directory is " << output_dir << endl;
cout << "Working directory is " << work_dir << endl;
cout << "Minimum angle is " << min_angle << endl;
cout << "Tile id is " << tile_id << endl;
cout << "Center longitude is " << lon << endl;
cout << "Center latitude is " << lat << endl;
@ -1132,7 +1104,6 @@ int main(int argc, char **argv) {
// main construction data management class
TGConstruct c;
c.set_angle( min_angle );
c.set_cover( cover );
c.set_work_base( work_dir );
c.set_output_base( output_dir );