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 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 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])