def do_supertile(lon, lat, zoom, size, margin=128):
"""render the supertile containing lon,lat
int zoom is the GYM tile zoom level.
size and margin are in pixels.
"""
tilesize = 256
# difference in zoom between tile and supertile
dzoom = math.log(size / tilesize, 2)
# build a grid where each cell is a supertile at the
# target resolution, and look up the requested location within
# that grid.
stgrid = Grid.gym_tiles(zoom - dzoom)
stx, sty = stgrid.ll2i(lon, lat)
# get a grid for all tiles at the requested zoom level
# that are contained in the supertile.
tilegrid = stgrid.expand_tile(int(stx), int(sty), size/tilesize)
# and get a grid for pixels within the supertile (this is the geoxf)
pixelgrid = stgrid.expand_tile(int(stx), int(sty), size)
# to handle boundary conditions, duplicate a margin around all
# edges of the supertile. the step that requires the largest
# margin is probably label placement?
workgrid = pixelgrid.with_margin(margin)
# request a directory for temporary files
workdir = request_workdir(workgrid)
# extract and render the supertile
img = doit(workdir, workgrid)
# clip off the margin (returning to pixelgrid) and save tiles
# destdir should not be on the ramdisk
destdir = os.path.join(workdir, 'tiles')
if not os.path.isdir(destdir):
os.makedirs(destdir)
save_tiles(workdir,
destdir,
zoom,
pixelgrid, img[margin:-margin,margin:-margin,:],
tilesize)
# save the whole thing as a tif for debugging
save_raster('%s/geo.tif' % (workdir,),
N.array(img*255, N.uint8),
attrdict(grid=workgrid))
return img
def build_quarter(fn, info, data):
"""output an image at half resolution in both x and y.
used to prepare for the next zoom level while the data is hot.
"""
# filter and downsample. could do this more gracefully with broadcasting?
if len(data.shape) == 2:
print "QD", data.shape, data.dtype
data = ndimage.zoom(data, 0.5)
print "QS", data.shape, data.dtype
elif len(data.shape) == 3:
print "QD", data.shape, data.dtype
outshape = (data.shape[0] / 2, data.shape[1] / 2, data.shape[2])
data = N.dstack([ndimage.zoom(data[:, :, ci], 0.5) for ci in range(data.shape[2])])
print "QS", data.shape, data.dtype
# should this be a convenience function in Grid?
# double the scale of pixels in the output
geoxf = [] + info.grid.geoxf()
for i in (1, 2, 4, 5):
geoxf[i] *= 2
qgrid = Grid(info.grid.srs(), geoxf=geoxf, shape=data.shape)
save_raster(fn, data, {"grid": qgrid})
def doit(workdir, grid):
extract_all(workdir, grid)
# create surface
lcf = '%s/mrlc' % (workdir,)
if os.path.exists(lcf + '.tif'):
sfcinfo, surface = load_mrlc(lcf + '.tif')
else:
sfcinfo, surface = load_quarters(lcf)
#print 'SFCI', sfcinfo
# get the hydrography
#water = map_nhd(sfcinfo.grid)
#print 'WWWWS', water.shape
#glumpy_loop(water)
demf = '%s/dem' % (workdir,)
demtif = demf + '.tif'
if os.path.exists(demtif):
deminfo, demlayers = load_raster(demtif)
else:
deminfo, demlayers = load_quarters(lcf)
dem = demlayers[0]
# XXX handle missing values
#glumpy_loop(surface)
shaded = reliefshade(deminfo, dem, surface)
#glumpy_loop(shaded)
# test of grid tiling
#for (z,ix,iy) in sfcinfo.grid.itertiles():
# print 'TILE %d %d %d' % (z, ix, iy)
#print 'TIFF_HISTO', N.histogram(img, new=True)
# if we don't have the DEM in a file (because we just composited it from quadrants),
# save it to a file so it can be fed to gdal_contour
if not os.path.exists(demtif):
save_raster(deminfo, demtif, dem)
if not os.path.isdir('%s/contour' % workdir):
contour_find(demtif, '%s/contour' % workdir)
if not os.path.isdir('%s/contourft' % (workdir,)):
ContourTweaker().filter('%s/contour' % (workdir,), '%s/contourft' % (workdir,))
feats = render_layer(workdir, 'features', grid, ['nhd_flowline', 'nhd_waterbody', 'nhd_area', 'osm_line', 'contours'])
fills = render_layer(workdir, 'fills', grid, ['contours', 'nhd_flowline', 'nhd_waterbody', 'nhd_area', 'osm_line'])
labels = render_layer(workdir, 'labels', grid, ['contours', 'nhd_flowline', 'nhd_waterbody', 'nhd_area', 'osm_line'])
# add contour labels and features
img = asum(shaded, halo_mask(feats, labels))
img = asum(img, fills)
img = asum(img, labels)
# build half-resolution versions for next zoom level
#if not os.path.isdir('%s/quarter' % (workdir,)):
# os.mkdir('%s/quarter' % (workdir,))
# XXX doesn't do anything right now
parentgrid = sfcinfo.grid
# XXX need to figure these out based on ix%2, iy%2 at some zoom?
is_east = 0
is_north = 0
quadrant = [['sw', 'se'], ['nw', 'ne']][is_north][is_east]
mrlcdir = request_workdir(parentgrid, 'mrlc')
build_quarter('%s/%s.tif' % (mrlcdir,quadrant), sfcinfo, surface)
demdir = request_workdir(parentgrid, 'dem')
build_quarter('%s/%s.tif' % (demdir,quadrant), deminfo, dem)
return img