streetview.py

#!/usr/bin/python

import urllib
import urllib2
import libxml2
import inspect
import sys
import zlib
import base64
import struct


BaseUri = 'http://maps.google.com/cbk';

# panoid is the value from panorama metadata
# OR: supply lat/lon/radius to find the nearest pano to lat/lon within radius
def GetPanoramaMetadata(panoid = None, lat = None, lon = None, radius = 2000):
	url =  '%s?'
	url += 'output=xml'			# metadata output
	url += '&v=4'				# version
	url += '&dm=1'				# include depth map
	url += '&pm=1'				# include pano map
	if panoid == None:
		url += '&ll=%s,%s'		# lat/lon to search at
		url += '&radius=%s'		# search radius
		url = url % (BaseUri, lat, lon, radius)
	else:
		url += '&panoid=%s'		# panoid to retrieve
		url = url % (BaseUri, panoid)
	
	findpanoxml = GetUrlContents(url)
	if not findpanoxml.find('data_properties'):
		return None
	return PanoramaMetadata(libxml2.parseDoc(findpanoxml))

# panoid is the value from the panorama metadata
# zoom range is 0->NumZoomLevels inclusively
# x/y range is 0->?
def GetPanoramaTile(panoid, zoom, x, y):
	url =  '%s?'
	url += 'output=tile'			# tile output
	url += '&panoid=%s'			# panoid to retrieve
	url += '&zoom=%s'			# zoom level of tile
	url += '&x=%i'				# x position of tile
	url += '&y=%i'				# y position of tile
	url += '&fover=2'			# ???
	url += '&onerr=3'			# ???
	url += '&renderer=spherical'		# standard speherical projection
	url += '&v=4'				# version
	url = url % (BaseUri, panoid, zoom, x, y)
	
	return GetUrlContents(url)

def GetUrlContents(url):
	f = urllib2.urlopen(url)
	data = f.read()
	f.close()
	return data

class PanoramaMetadata:
	
	def __init__(self, panodoc):
		self.PanoDoc = panodoc
		panoDocCtx = self.PanoDoc.xpathNewContext()

		self.PanoId = panoDocCtx.xpathEval("/panorama/data_properties/@pano_id")[0].content
		self.ImageWidth = panoDocCtx.xpathEval("/panorama/data_properties/@image_width")[0].content
		self.ImageHeight = panoDocCtx.xpathEval("/panorama/data_properties/@image_height")[0].content
		self.TileWidth = panoDocCtx.xpathEval("/panorama/data_properties/@tile_width")[0].content
		self.TileHeight = panoDocCtx.xpathEval("/panorama/data_properties/@tile_height")[0].content
		self.NumZoomLevels = panoDocCtx.xpathEval("/panorama/data_properties/@num_zoom_levels")[0].content
		self.Lat = panoDocCtx.xpathEval("/panorama/data_properties/@lat")[0].content
		self.Lon = panoDocCtx.xpathEval("/panorama/data_properties/@lng")[0].content
		self.OriginalLat = panoDocCtx.xpathEval("/panorama/data_properties/@original_lat")[0].content
		self.OriginalLon = panoDocCtx.xpathEval("/panorama/data_properties/@original_lng")[0].content
		self.Copyright = panoDocCtx.xpathEval("/panorama/data_properties/copyright/text()")[0].content
		self.Text = panoDocCtx.xpathEval("/panorama/data_properties/text/text()")[0].content
		self.Region = panoDocCtx.xpathEval("/panorama/data_properties/region/text()")[0].content
		self.Country = panoDocCtx.xpathEval("/panorama/data_properties/country/text()")[0].content

		self.ProjectionType = panoDocCtx.xpathEval("/panorama/projection_properties/@projection_type")[0].content
		self.ProjectionPanoYawDeg = panoDocCtx.xpathEval("/panorama/projection_properties/@pano_yaw_deg")[0].content
		self.ProjectionTiltYawDeg = panoDocCtx.xpathEval("/panorama/projection_properties/@tilt_yaw_deg")[0].content
		self.ProjectionTiltPitchDeg = panoDocCtx.xpathEval("/panorama/projection_properties/@tilt_pitch_deg")[0].content
		
		self.AnnotationLinks = []
		for cur in panoDocCtx.xpathEval("/panorama/annotation_properties/link"):
			self.AnnotationLinks.append({ 'YawDeg': cur.xpathEval("@yaw_deg")[0].content,
					    'PanoId': cur.xpathEval("@pano_id")[0].content,
					    'RoadARGB': cur.xpathEval("@road_argb")[0].content,
					    'Text': cur.xpathEval("link_text/text()")[0].content,
			})
		
		tmp = panoDocCtx.xpathEval("/panorama/model/pano_map/text()")
		if len(tmp) > 0:
			tmp = tmp[0].content
			tmp = zlib.decompress(base64.urlsafe_b64decode(tmp + self.MakePadding(tmp)))			
			self.DecodePanoMap(tmp)
		
		tmp = panoDocCtx.xpathEval("/panorama/model/depth_map/text()")
		if len(tmp) > 0:
			tmp = tmp[0].content
			tmp = zlib.decompress(base64.urlsafe_b64decode(tmp + self.MakePadding(tmp)))
			self.DecodeDepthMap(tmp)


	def MakePadding(self, s):
		return (4 - (len(s) % 4)) * '='


	def DecodePanoMap(self, raw):
		pos = 0
		
		(headerSize, numPanos, panoWidth, panoHeight, panoIndicesOffset) = struct.unpack('<BHHHB', raw[0:8])
		if headerSize != 8 or panoIndicesOffset != 8:
			print "Invalid panomap data"
			return
		pos += headerSize
		
		self.PanoMapIndices = [ord(x) for x in raw[panoIndicesOffset:panoIndicesOffset + (panoWidth * panoHeight)]]
		pos += len(self.PanoMapIndices)
		
		self.PanoMapPanos = []
		for i in xrange(0, numPanos - 1):
			self.PanoMapPanos.append({ 'panoid': raw[pos: pos+ 22]})
			pos += 22
			
		for i in xrange(0, numPanos - 1):
			(x, y) = struct.unpack('<ff', raw[pos:pos+8])
			self.PanoMapPanos[i]['x'] = x
			self.PanoMapPanos[i]['y'] = y
			pos+=8

	def DecodeDepthMap(self, raw):
		pos = 0

		(headerSize, numPlanes, panoWidth, panoHeight, planeIndicesOffset) = struct.unpack('<BHHHB', raw[0:8])
		if headerSize != 8 or planeIndicesOffset != 8:
			print "Invalid depthmap data"
			return
		pos += headerSize

		self.DepthMapIndices = [ord(x) for x in raw[planeIndicesOffset:planeIndicesOffset + (panoWidth * panoHeight)]]
		pos += len(self.DepthMapIndices)

		self.DepthMapPlanes = []
		for i in xrange(0, numPlanes - 1):
			(d, nx, ny, nz) = struct.unpack('<ffff', raw[pos:pos+16])

			self.DepthMapPlanes.append({ 'd': d, 'nx': nx, 'ny': ny, 'nz': nz }) # nx/ny/nz = unit normal, d = distance from origin
			pos += 16

	def __str__(self):
		tmp = ''
		for x in inspect.getmembers(self):
			if x[0].startswith("__") or inspect.ismethod(x[1]):
				continue
			
			tmp += "%s: %s\n" % x
		return tmp

pano = GetPanoramaMetadata(lat=27.683528, lon=-99.580078)
#print pano.PanoId
#print pano.PanoMapPanos
#print pano.DepthMapPlanes
print GetPanoramaTile(pano.PanoId, 2, 0, 0)

148 (d, nx, ny, nz) = struct.unpack('<ffff', raw[pos:pos+16])
After my test, I think it should be (nx, ny, nz, d) = struct.unpack('<ffff', raw[pos:pos+16])