def readTile(self, lat0, lon0):
# We need the tile name to know which row key to get.
tileName = tileFromLatLon(lat0,lon0)
print tileName
# Calculate begin and end position
begin = posFromLatLon(lat0,lon0)
end = posFromLatLon(lat0 + 1, lon0 + 1)
try:
data = self.cf.get(tileName, column_start=int(begin), column_finish=int(end))
res = data.values()
except Exception:
res = []
# Now turn the result into a 2D array
tile = []
# Calculate tile width (should be 1200, or 10 for test tiles)
tile_width = int(sqrt(len(res)))
i = 0
for x in range(tile_width):
row = []
for y in range(tile_width):
row.append(int(res[i]))
i = i + 1
tile.append(row)
print tile
return tile
def readTile(self, lat0, lon0):
# Calculate begin and end position
begin = posFromLatLon(lat0,lon0)
end = posFromLatLon(lat0 + 1, lon0 + 1)
sql = self.db.query(" \
SELECT \
alt \
FROM altitude \
WHERE \
pos >= " + str(begin) + "\
AND pos < " + str(end) + "\
ORDER BY pos ASC \
")
res = sql.getresult()
# Now turn the result into a 2D array
tile = []
# Calculate tile width (should be 1200, or 10 for test tiles)
tile_width = int(sqrt(len(res)))
i = 0
for x in range(tile_width):
row = []
for y in range(tile_width):
row.append(int(res[i][0]))
i = i + 1
tile.append(row)
return tile
def insertTile(self, tile, lat0, lon0):
# We need the tile name to know which row key to get.
tileName = tileFromLatLon(lat0, lon0)
#print "tileName:", tileName
# Calculate begin position
begin = posFromLatLon(lat0,lon0)
# We want to accumulate a bunch of columns before we insert into Cassandra.
columns = {}
i=0
insert_max=25000
# We drop the top row and right column.
for row in range(1, len(tile)):
for col in range(0, len(tile) - 1):
alt = long(tile[row][col])
key = long(begin + (row-1) * 1200 + col)
#print key, alt
columns[key] = int(alt)
# We've reached our ceiling, insert.
# We could do a bulk insert but since we're hitting one key, a single mutation should be more efficient.
if i == insert_max:
self.cf.insert(tileName, columns)
columns = {}
i=0
else:
i+=1
# Send insert any thing left after the loop exits.
self.cf.insert(tileName, columns);
def insertTile(self, tile, lat0, lon0):
# I use the Psycopg2 connection, with its copy_to and
# copy_from commands, which use the more efficient COPY command.
# This method requires a temporary file.
# Calculate begin position
begin = posFromLatLon(lat0,lon0)
# First we write the data into a temporary file.
f = cStringIO.StringIO()
# int16 to string conversion is really slow, so we speed things up with caching
cache = {}
# We drop the top row and right column.
for row in range(1, len(tile)):
for col in range(0, len(tile) - 1):
alt = tile[row][col]
if not cache.has_key(alt):
cache[alt] = str(alt)
alt = cache[alt]
f.write(str(begin + (row-1) * 1200 + col) + "\t" + alt + "\n")
# Now we read the data from the temporary file and put it in the
# altitude table.
f.seek(0)
self.cursor.copy_from(f, 'altitude')
f.close()
def fetchTopLeftAltitude(self, lat, lon):
tileName = tileFromLatLon(lat,lon)
pos = posFromLatLon(lat,lon)
try:
res = self.cf.get(tileName, columns=[pos])
except Exception:
res = []
return int(res[pos])
def fetchTopLeftAltitude(self, lat, lon):
pos = posFromLatLon(lat,lon)
sql = self.db.query(" \
SELECT \
alt \
FROM altitude \
WHERE \
pos = " + str(pos) + "\
")
return int(sql.getresult()[0][0])
def testPosFromLatLon(self): self.assertEqual(posFromLatLon(0,0),0) self.assertEqual(posFromLatLon(0,1),1200*1200) self.assertEqual(posFromLatLon(0,2),1200*1200*2) self.assertEqual(posFromLatLon(1,0),1200*1200*360) self.assertEqual(posFromLatLon(0,-1),-1200*1200) self.assertEqual(posFromLatLon(-37,145),(-37 * 360 + 145) * 1200 * 1200)
def testPosFromLatLon(self): self.assertEqual(posFromLatLon(0,0),0) self.assertEqual(posFromLatLon(0,1),1200*1200) self.assertEqual(posFromLatLon(0,2),1200*1200*2) self.assertEqual(posFromLatLon(1,0),1200*1200*360) self.assertEqual(posFromLatLon(0,-1),-1200*1200) self.assertEqual(posFromLatLon(-37,145),(-37 * 360 + 145) * 1200 * 1200)
def writeTileCsvFile(tile, lat0, lon0, top_row = 1, bottom_row = 1200, left_col = 0, right_col = 1199 ):
# Calculate begin position
begin = posFromLatLon(lat0,lon0)
# First we write the data into a temporary file.
f = open('data/tile.csv', 'w')
# We drop the top row and right column.
for row in range(top_row, bottom_row + 1 ):
for col in range(left_col, right_col + 1):
f.write(str(\
begin + (row-1) * 1200 + col\
) + ", " + str(tile[row][col] ) + "\n")
f.close()
def readTile(self, lat0, lon0):
# Calculate begin and end position
begin = posFromLatLon(lat0,lon0)
end = posFromLatLon(lat0 + 1, lon0 + 1)
sql = "SELECT alt FROM altitude WHERE pos >= %s AND pos < %s ORDER BY pos ASC"
res = self.query(sql, (str(begin),str(end)))
# Now turn the result into a 2D array
tile = []
# Calculate tile width (should be 1200, or 10 for test tiles)
tile_width = int(sqrt(len(res)))
i = 0
for x in range(tile_width):
row = []
for y in range(tile_width):
row.append(int(res[i][0]))
i = i + 1
tile.append(row)
return tile
def writeTileCsvFile(tile,
lat0,
lon0,
top_row=1,
bottom_row=1200,
left_col=0,
right_col=1199):
# Calculate begin position
begin = posFromLatLon(lat0, lon0)
# First we write the data into a temporary file.
f = open('data/tile.csv', 'w')
# We drop the top row and right column.
for row in range(top_row, bottom_row + 1):
for col in range(left_col, right_col + 1):
f.write(str(\
begin + (row-1) * 1200 + col\
) + ", " + str(tile[row][col] ) + "\n")
f.close()
def insertTile(self, tile, lat0, lon0):
# I use the Psycopg2 connection, with its copy_to and
# copy_from commands, which use the more efficient COPY command.
# This method requires a temporary file.
# Calculate begin position
begin = posFromLatLon(lat0,lon0)
# First we write the data into a temporary file.
f = open('/tmp/tempcopy', 'w')
# We drop the top row and right column.
for row in range(1, len(tile)):
for col in range(0, len(tile) - 1):
f.write(str(\
begin + (row-1) * 1200 + col\
) + "\t" + str(tile[row][col] ) + "\n")
f.close()
# Now we read the data from the temporary file and put it in the
# altitude table.
f = open('/tmp/tempcopy', 'r')
#cur.copy_from(f, 'altitude')
# Unfortunately the copy_from() command hangs on my computer for
# some reason, so we try something else. See also:
# http://lists.initd.org/pipermail/psycopg/2007-October/005684.html
import subprocess
#psqlcmd = os.path.join('c:\\', 'Program Files', 'PostgreSQL', '8.2',
#'bin', 'psql')
psqlcmd = "/usr/bin/psql"
p = subprocess.Popen('psql ' + self.db_name + ' -c "COPY altitude FROM STDIN;"', stdin=f, shell=True);
p.wait()
f.close
def fetchTopLeftAltitude(self, lat, lon): pos = posFromLatLon(lat,lon) sql = " SELECT alt FROM altitude WHERE pos = %s " return int(self.query(sql, (pos,))[0][0])