source: anuga_core/source/anuga/pmesh/mesh_interface.py @ 7699

from anuga.coordinate_transforms.geo_reference import Geo_reference,DEFAULT_ZONE
from anuga.utilities.polygon import  point_in_polygon ,populate_polygon
from anuga.utilities.numerical_tools import ensure_numeric
import numpy as num
from anuga.utilities.polygon import inside_polygon
from anuga.utilities.polygon import polylist2points_verts
import anuga.utilities.log as log


# This is due to pmesh being a package and a module and
# the current dir being unknown 
try:
    from anuga.pmesh.mesh import Mesh
except ImportError:  
    from mesh import Mesh

import exceptions
class PolygonError(exceptions.Exception): pass
class SegmentError(exceptions.Exception): pass

def create_mesh_from_regions(bounding_polygon,
                             boundary_tags,
                             maximum_triangle_area=None,
                             filename=None,
                             interior_regions=None,
                             interior_holes=None,
                             poly_geo_reference=None,
                             mesh_geo_reference=None,
                             minimum_triangle_angle=28.0,
                             fail_if_polygons_outside=True,
                             breaklines=None,
                             use_cache=False,
                             verbose=True):
    """Create mesh from bounding polygons, and resolutions.

    bounding_polygon is a list of points in Eastings and Northings,
    relative to the poly_geo_reference.

    Boundary tags is a dictionary of symbolic tags. For every tag there
    is a list of indices referring to segments associated with that tag.
    If a segment is omitted an Exception will be raised.

    maximum_triangle_area is the maximal area per triangle
    for the bounding polygon, excluding the  interior regions.

    Interior_regions is a list of tuples consisting of (polygon,
    resolution) for each region to be separately refined. Do not have
    polygon lines cross or be on-top of each other.  Also do not have
    polygon close to each other.
    
    NOTE: If a interior_region is outside the bounding_polygon it should 
    throw an error
    
    Interior_holes is a list of ploygons for each hole.

    This function does not allow segments to share points - use underlying
    pmesh functionality for that

    poly_geo_reference is the geo_reference of the bounding polygon and
    the interior polygons.
    If none, assume absolute.  Please pass one though, since absolute
    references have a zone.
    
    mesh_geo_reference is the geo_reference of the mesh to be created.
    If none is given one will be automatically generated.  It was use
    the lower left hand corner of  bounding_polygon (absolute)
    as the x and y values for the geo_ref.

    breaklines is a list of polygons. These lines will be preserved by the
               triangulation algorithm - useful for coastlines, walls, etc.
               The polygons are not closed.                        
    
    Returns the mesh instance if no filename is given

    Note, interior regions should be fully nested, as overlaps may cause
    unintended resolutions. 

    fail_if_polygons_outside: If True (the default) Exception in thrown
    where interior polygons fall outside bounding polygon. If False, these
    will be ignored and execution continued.
        
    
    """
    
    # Build arguments and keyword arguments for use with caching or apply.
    args = (bounding_polygon,
            boundary_tags)
    
    kwargs = {'maximum_triangle_area': maximum_triangle_area,
              'filename': filename,
              'interior_regions': interior_regions,
              'interior_holes': interior_holes,
              'poly_geo_reference': poly_geo_reference,
              'mesh_geo_reference': mesh_geo_reference,
              'minimum_triangle_angle': minimum_triangle_angle,
              'fail_if_polygons_outside': fail_if_polygons_outside,
              'breaklines': breaklines,
              'verbose': verbose}   # FIXME (Ole): Should be bypassed one day. See ticket:14

    # Call underlying engine with or without caching
    if use_cache is True:
        try:
            from anuga.caching import cache
        except:
            msg = 'Caching was requested, but caching module'+\
                  'could not be imported'
            raise msg


        m = cache(_create_mesh_from_regions,
                  args, kwargs,
                  verbose=verbose,
                  compression=False)
    else:
        m = apply(_create_mesh_from_regions,
                  args, kwargs)

    return m    
        


def _create_mesh_from_regions(bounding_polygon,
                              boundary_tags,
                              maximum_triangle_area=None,
                              filename=None,                              
                              interior_regions=None,
                              interior_holes=None,
                              poly_geo_reference=None,
                              mesh_geo_reference=None,
                              minimum_triangle_angle=28.0,
                              fail_if_polygons_outside=True,
                              breaklines=None,
                              verbose=True):
    """_create_mesh_from_regions - internal function.

    See create_mesh_from_regions for documentation.
    """

    
    # check the segment indexes - throw an error if they are out of bounds
    if boundary_tags is not None:
        max_points = len(bounding_polygon)
        for key in boundary_tags.keys():
            if len([x for x in boundary_tags[key] if x > max_points-1]) >= 1:
                msg = 'Boundary tag %s has segment out of bounds. '\
                      %(str(key))
                msg += 'Number of points in bounding polygon = %d' % max_points
                raise SegmentError, msg

        for i in range(max_points):
            found = False
            for tag in boundary_tags:
                if i in boundary_tags[tag]:
                    found = True
            if found is False:
                msg = 'Segment %d was not assigned a boundary_tag.' % i
                msg +=  'Default tag "exterior" will be assigned to missing segment'
                #raise Exception, msg
                # Fixme: Use proper Python warning
                if verbose: log.critical('WARNING: %s' % msg)
                

    
    #In addition I reckon the polygons could be of class Geospatial_data 
    #(DSG) If polygons were classes caching would break in places.

    # Simple check
    bounding_polygon = ensure_numeric(bounding_polygon, num.float)
    msg = 'Bounding polygon must be a list of points or an Nx2 array'
    assert len(bounding_polygon.shape) == 2, msg
    assert bounding_polygon.shape[1] == 2, msg    

    # 
    if interior_regions is not None:
        
        # Test that all the interior polygons are inside the
        # bounding_poly and throw out those that aren't fully
        # included.  #Note, Both poly's have the same geo_ref,
        # therefore don't take into account # geo_ref


        polygons_inside_boundary = []
        for interior_polygon, res in interior_regions:
            indices = inside_polygon(interior_polygon, bounding_polygon,
                                     closed = True, verbose = False)
    
            if len(indices) <> len(interior_polygon): 
                msg = 'Interior polygon %s is not fully inside'\
                      %(str(interior_polygon))
                msg += ' bounding polygon: %s.' %(str(bounding_polygon))

                if fail_if_polygons_outside is True:
                    raise PolygonError, msg                    
                else:
                    msg += ' I will ignore it.'
                    log.critical(msg)

            else:
                polygons_inside_boundary.append([interior_polygon, res])
                
        # Record only those that were fully contained        
        interior_regions = polygons_inside_boundary

            
    
# the following segment of code could be used to Test that all the 
# interior polygons are inside the bounding_poly... however it might need 
# to be change a bit   
#
#count = 0
#for i in range(len(interior_regions)):
#    region = interior_regions[i]
#    interior_polygon = region[0]
#    if len(inside_polygon(interior_polygon, bounding_polygon,
#                   closed = True, verbose = False)) <> len(interior_polygon):
#        print 'WARNING: interior polygon %d is outside bounding polygon' %(i)
#        count += 1

#if count == 0:
#    print 'interior regions OK'
#else:
#    print 'check out your interior polygons'
#    print 'check %s in production directory' %figname
#    import sys; sys.exit()

    if interior_holes is not None:        
        # Test that all the interior polygons are inside the bounding_poly
        for interior_polygon in interior_holes:
            indices = inside_polygon(interior_polygon, bounding_polygon,
                                     closed = True, verbose = False)
    
            if len(indices) <> len(interior_polygon): 
                msg = 'Interior polygon %s is outside bounding polygon: %s'\
                      %(str(interior_polygon), str(bounding_polygon))
                raise PolygonError, msg

    # Resolve geo referencing        
    if mesh_geo_reference is None:
        xllcorner = min(bounding_polygon[:,0])
        yllcorner = min(bounding_polygon[:,1])    
        #
        if poly_geo_reference is None:
            zone = DEFAULT_ZONE
        else:
            zone = poly_geo_reference.get_zone()
            [(xllcorner,yllcorner)] = poly_geo_reference.get_absolute( \
            [(xllcorner,yllcorner)])
        # create a geo_ref, based on the llc of the bounding_polygon
        mesh_geo_reference = Geo_reference(xllcorner = xllcorner,
                                           yllcorner = yllcorner,
                                           zone = zone)

    m = Mesh(geo_reference=mesh_geo_reference)

    # build a list of discrete segments from the breakline polygons
    if breaklines is not None:
        points, verts = polylist2points_verts(breaklines)
        m.add_points_and_segments(points, verts)

    # Do bounding polygon
    m.add_region_from_polygon(bounding_polygon,
                              segment_tags=boundary_tags,
                              geo_reference=poly_geo_reference)

    # Find one point inside region automatically
    if interior_regions is not None:
        excluded_polygons = []        
        for polygon, res in interior_regions:
            excluded_polygons.append( polygon )
    else:
        excluded_polygons = None

    # Convert bounding poly to absolute values
    # this sort of thing can be fixed with the geo_points class
    if poly_geo_reference is not None:
        bounding_polygon_absolute = \
            poly_geo_reference.get_absolute(bounding_polygon)
    else:
        bounding_polygon_absolute = bounding_polygon
    
    inner_point = point_in_polygon(bounding_polygon_absolute)
    inner = m.add_region(inner_point[0], inner_point[1])
    inner.setMaxArea(maximum_triangle_area)

    # Do interior regions
#    if interior_regions is not None:    
#        for polygon, res in interior_regions:
#            m.add_region_from_polygon(polygon,
#                                      geo_reference=poly_geo_reference)
#            # convert bounding poly to absolute values
#            if poly_geo_reference is not None:
#                polygon_absolute = \
#                    poly_geo_reference.get_absolute(polygon)
#            else:
#                polygon_absolute = polygon
#            inner_point = point_in_polygon(polygon_absolute)
#            region = m.add_region(inner_point[0], inner_point[1])
#            region.setMaxArea(res)
            
            
    if interior_regions is not None:    
        for polygon, res in interior_regions:
            m.add_region_from_polygon(polygon,
                                      max_triangle_area=res,
                                      geo_reference=poly_geo_reference)
    
            
    # Do interior holes
    if interior_holes is not None:    
        for polygon in interior_holes:
            m.add_hole_from_polygon(polygon,
                                    geo_reference=poly_geo_reference)
       


    # NOTE (Ole): This was moved here as it is annoying if mesh is always
    # stored irrespective of whether the computation
    # was cached or not. This caused Domain to
    # recompute as it has meshfile as a dependency

    # Decide whether to store this mesh or return it    
    if filename is None:
        return m
    else:
        if verbose: log.critical("Generating mesh to file '%s'" % filename)
        m.generate_mesh(minimum_triangle_angle=minimum_triangle_angle,
                        verbose=verbose)
        m.export_mesh_file(filename)