def projCoordinate(self, point):
""" Convert from Point object in EPSG:900913 to a Coordinate object
"""
# the zoom at which we're dealing with meters on the ground
diameter = 2 * _pi * 6378137
zoom = _log(diameter) / _log(2)
# global offsets
coord = Coordinate(point.y, point.x, zoom)
coord.column = coord.column + diameter/2
coord.row = diameter/2 - coord.row
return coord
def projCoordinate(self, point):
""" Convert from Point object in EPSG:3857 to a Coordinate object
"""
# the zoom at which we're dealing with meters on the ground
diameter = 2 * _pi * 6378137
zoom = _log(diameter) / _log(2)
# global offsets
coord = Coordinate(point.y, point.x, zoom)
coord.column = coord.column + diameter/2
coord.row = diameter/2 - coord.row
return coord
def generatePyramid(projection, top_tile, zooms):
""" Generate a stream of (offset, count, coordinate) tuples for seeding.
"""
print('Projection', projection)
if (projection.__class__.__name__ == 'WGS84'):
print('Skip')
else:
bounds_ul = projection.coordinateProj(top_tile)
bounds_lr = projection.coordinateProj(top_tile.down().right())
print('Pyramid top tile bounds in projection units', bounds_ul,
bounds_lr)
print bounds_ul.__class__
pyramid_start = projection.projCoordinate(bounds_ul, zooms[-1])
pyramid_end = projection.projCoordinate(bounds_lr, zooms[-1])
print('Tile grid extent of bottom of pyramid', pyramid_start,
pyramid_end)
# start with a simple total of all the coordinates we will need.
count = 0
for zoom in zooms:
if (projection.__class__.__name__ == 'WGS84'):
pyramid_start = Coordinate(0, 0, zoom)
pyramid_end = Coordinate(2**zoom - 1, 2 * 2**zoom - 1, zoom)
else:
pyramid_start = projection.projCoordinate(bounds_ul, zoom)
pyramid_end = projection.projCoordinate(bounds_lr, zoom)
pyramid_end.row = pyramid_end.row - 1
pyramid_end.column = pyramid_end.column - 1
columns = pyramid_end.column - pyramid_start.column
rows = pyramid_end.row - pyramid_start.row
count += columns * rows
# now generate the actual coordinates.
# offset starts at zero
offset = 0
for zoom in zooms:
print projection.__class__.__name__
if (projection.__class__.__name__ == 'WGS84'):
pyramid_start = Coordinate(0, 0, zoom)
pyramid_end = Coordinate(2**zoom - 1, 2 * 2**zoom - 1, zoom)
else:
pyramid_start = projection.projCoordinate(bounds_ul, zoom)
pyramid_end = projection.projCoordinate(bounds_lr, zoom)
pyramid_end.row = pyramid_end.row - 1
pyramid_end.column = pyramid_end.column - 1
print('Tile grid extent at zoom ' + str(zoom), pyramid_start,
pyramid_end)
for column in xrange(pyramid_start.column, pyramid_end.column + 1):
for row in xrange(pyramid_start.row, pyramid_end.row + 1):
coord = Coordinate(row, column, zoom)
yield (offset, count, coord)
offset += 1
