mirror of https://github.com/ArduPilot/ardupilot
AP_Terrain: added script for creating terrain *.dat files
useful for pre-populating a microSD card
This commit is contained in:
Andrew Tridgell
parent
dee9e85307
commit
0aa367d5ca
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#!/usr/bin/env python
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'''
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create ardupilot terrain database files
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'''
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from MAVProxy.modules.mavproxy_map import srtm
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import math, struct, os, sys
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import crc16, time, struct
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# MAVLink sends 4x4 grids
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TERRAIN_GRID_MAVLINK_SIZE = 4
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# a 2k grid_block on disk contains 8x7 of the mavlink grids. Each
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# grid block overlaps by one with its neighbour. This ensures that
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# the altitude at any point can be calculated from a single grid
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# block
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TERRAIN_GRID_BLOCK_MUL_X = 7
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TERRAIN_GRID_BLOCK_MUL_Y = 8
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# this is the spacing between 32x28 grid blocks, in grid_spacing units
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TERRAIN_GRID_BLOCK_SPACING_X = ((TERRAIN_GRID_BLOCK_MUL_X-1)*TERRAIN_GRID_MAVLINK_SIZE)
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TERRAIN_GRID_BLOCK_SPACING_Y = ((TERRAIN_GRID_BLOCK_MUL_Y-1)*TERRAIN_GRID_MAVLINK_SIZE)
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# giving a total grid size of a disk grid_block of 32x28
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TERRAIN_GRID_BLOCK_SIZE_X = (TERRAIN_GRID_MAVLINK_SIZE*TERRAIN_GRID_BLOCK_MUL_X)
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TERRAIN_GRID_BLOCK_SIZE_Y = (TERRAIN_GRID_MAVLINK_SIZE*TERRAIN_GRID_BLOCK_MUL_Y)
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# format of grid on disk
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TERRAIN_GRID_FORMAT_VERSION = 1
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IO_BLOCK_SIZE = 2048
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GRID_SPACING = 100
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def to_float32(f):
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'''emulate single precision float'''
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return struct.unpack('f', struct.pack('f',f))[0]
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LOCATION_SCALING_FACTOR = to_float32(0.011131884502145034)
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LOCATION_SCALING_FACTOR_INV = to_float32(89.83204953368922)
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def longitude_scale(lat):
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'''get longitude scale factor'''
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scale = to_float32(math.cos(to_float32(math.radians(lat))))
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return max(scale, 0.01)
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def get_distance_NE_e7(lat1, lon1, lat2, lon2):
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'''get distance tuple between two positions in 1e7 format'''
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return ((lat2 - lat1) * LOCATION_SCALING_FACTOR, (lon2 - lon1) * LOCATION_SCALING_FACTOR * longitude_scale(lat1*1.0e-7))
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def add_offset(lat_e7, lon_e7, ofs_north, ofs_east):
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'''add offset in meters to a position'''
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dlat = int(float(ofs_north) * LOCATION_SCALING_FACTOR_INV)
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dlng = int((float(ofs_east) * LOCATION_SCALING_FACTOR_INV) / longitude_scale(lat_e7*1.0e-7))
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return (int(lat_e7+dlat), int(lon_e7+dlng))
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def east_blocks(lat_e7, lon_e7):
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'''work out how many blocks per stride on disk'''
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lat2_e7 = lat_e7
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lon2_e7 = lon_e7 + 10*1000*1000
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# shift another two blocks east to ensure room is available
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lat2_e7, lon2_e7 = add_offset(lat2_e7, lon2_e7, 0, 2*GRID_SPACING*TERRAIN_GRID_BLOCK_SIZE_Y)
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offset = get_distance_NE_e7(lat_e7, lon_e7, lat2_e7, lon2_e7)
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return int(offset[1] / (GRID_SPACING*TERRAIN_GRID_BLOCK_SPACING_Y))
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def pos_from_file_offset(lat_degrees, lon_degrees, file_offset):
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'''return a lat/lon in 1e7 format given a file offset'''
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ref_lat = int(lat_degrees*10*1000*1000)
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ref_lon = int(lon_degrees*10*1000*1000)
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stride = east_blocks(ref_lat, ref_lon)
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blocks = file_offset // IO_BLOCK_SIZE
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grid_idx_x = blocks // stride
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grid_idx_y = blocks % stride
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idx_x = grid_idx_x * TERRAIN_GRID_BLOCK_SPACING_X
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idx_y = grid_idx_y * TERRAIN_GRID_BLOCK_SPACING_Y
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offset = (idx_x * GRID_SPACING, idx_y * GRID_SPACING)
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(lat_e7, lon_e7) = add_offset(ref_lat, ref_lon, offset[0], offset[1])
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offset = get_distance_NE_e7(ref_lat, ref_lon, lat_e7, lon_e7)
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grid_idx_x = int(idx_x / TERRAIN_GRID_BLOCK_SPACING_X)
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grid_idx_y = int(idx_y / TERRAIN_GRID_BLOCK_SPACING_Y)
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(lat_e7, lon_e7) = add_offset(ref_lat, ref_lon,
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grid_idx_x * TERRAIN_GRID_BLOCK_SPACING_X * float(GRID_SPACING),
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grid_idx_y * TERRAIN_GRID_BLOCK_SPACING_Y * float(GRID_SPACING))
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return (lat_e7, lon_e7)
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class GridBlock(object):
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def __init__(self, lat_int, lon_int, lat, lon):
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'''
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a grid block is a structure in a local file containing height
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information. Each grid block is 2048 bytes in size, to keep file IO to
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block oriented SD cards efficient
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'''
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# crc of whole block, taken with crc=0
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self.crc = 0
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# format version number
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self.version = TERRAIN_GRID_FORMAT_VERSION
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# grid spacing in meters
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self.spacing = GRID_SPACING
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# heights in meters over a 32*28 grid
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self.height = []
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for x in range(TERRAIN_GRID_BLOCK_SIZE_X):
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self.height.append([0]*TERRAIN_GRID_BLOCK_SIZE_Y)
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# bitmap of 4x4 grids filled in from GCS (56 bits are used)
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self.bitmap = (1<<56)-1
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lat_e7 = int(lat * 1.0e7)
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lon_e7 = int(lon * 1.0e7)
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# grids start on integer degrees. This makes storing terrain data on
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# the SD card a bit easier. Note that this relies on the python floor
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# behaviour with integer division
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self.lat_degrees = lat_int
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self.lon_degrees = lon_int
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# create reference position for this rounded degree position
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ref_lat = self.lat_degrees*10*1000*1000
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ref_lon = self.lon_degrees*10*1000*1000
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# find offset from reference
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offset = get_distance_NE_e7(ref_lat, ref_lon, lat_e7, lon_e7)
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offset = (round(offset[0]), round(offset[1]))
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# get indices in terms of grid_spacing elements
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idx_x = int(offset[0] / GRID_SPACING)
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idx_y = int(offset[1] / GRID_SPACING)
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# find indexes into 32*28 grids for this degree reference. Note
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# the use of TERRAIN_GRID_BLOCK_SPACING_{X,Y} which gives a one square
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# overlap between grids
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self.grid_idx_x = idx_x // TERRAIN_GRID_BLOCK_SPACING_X
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self.grid_idx_y = idx_y // TERRAIN_GRID_BLOCK_SPACING_Y
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# calculate lat/lon of SW corner of 32*28 grid_block
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(ref_lat, ref_lon) = add_offset(ref_lat, ref_lon,
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self.grid_idx_x * TERRAIN_GRID_BLOCK_SPACING_X * float(GRID_SPACING),
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self.grid_idx_y * TERRAIN_GRID_BLOCK_SPACING_Y * float(GRID_SPACING))
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self.lat = ref_lat
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self.lon = ref_lon
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def fill(self, gx, gy, altitude):
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'''fill a square'''
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self.height[gx][gy] = int(altitude)
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def blocknum(self):
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'''find IO block number'''
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stride = east_blocks(self.lat_degrees*1e7, self.lon_degrees*1e7)
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return stride * self.grid_idx_x + self.grid_idx_y
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class DataFile(object):
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def __init__(self, lat, lon):
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if lat < 0:
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NS = 'S'
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else:
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NS = 'N'
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if lon < 0:
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EW = 'W'
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else:
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EW = 'E'
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name = "terrain/%c%02u%c%03u.DAT" % (NS, min(abs(int(lat)), 99),
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EW, min(abs(int(lon)), 999))
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try:
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os.mkdir("terrain")
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except Exception:
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pass
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if not os.path.exists(name):
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self.fh = open(name, 'w+b')
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else:
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self.fh = open(name, 'r+b')
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def seek_offset(self, block):
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'''seek to right offset'''
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# work out how many longitude blocks there are at this latitude
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file_offset = block.blocknum() * IO_BLOCK_SIZE
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self.fh.seek(file_offset)
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def pack(self, block):
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'''pack into a block'''
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buf = bytes()
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buf += struct.pack("<QiiHHH", block.bitmap, block.lat, block.lon, block.crc, block.version, block.spacing)
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for gx in range(TERRAIN_GRID_BLOCK_SIZE_X):
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buf += struct.pack("<%uh" % TERRAIN_GRID_BLOCK_SIZE_Y, *block.height[gx])
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buf += struct.pack("<HHhb", block.grid_idx_x, block.grid_idx_y, block.lon_degrees, block.lat_degrees)
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return buf
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def write(self, block):
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'''write a grid block'''
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self.seek_offset(block)
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block.crc = 0
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buf = self.pack(block)
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block.crc = crc16.crc16xmodem(buf)
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buf = self.pack(block)
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self.fh.write(buf)
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def check_filled(self, block):
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'''read a grid block and check if already filled'''
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self.seek_offset(block)
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buf = self.fh.read(IO_BLOCK_SIZE)
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if len(buf) != IO_BLOCK_SIZE:
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return False
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(bitmap, lat, lon, crc, version, spacing) = struct.unpack("<QiiHHH", buf[:22])
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if (version != TERRAIN_GRID_FORMAT_VERSION or
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abs(lat - block.lat)>2 or
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abs(lon - block.lon)>2 or
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spacing != GRID_SPACING or
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bitmap != (1<<56)-1):
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return False
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buf = buf[:16] + struct.pack("<H", 0) + buf[18:]
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crc2 = crc16.crc16xmodem(buf[:1821])
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if crc2 != crc:
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return False
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return True
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def create_degree(lat, lon):
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'''create data file for one degree lat/lon'''
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lat_int = int(math.floor(lat))
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lon_int = int(math.floor((lon)))
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tiles = {}
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dfile = DataFile(lat_int, lon_int)
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print("Creating for %d %d" % (lat_int, lon_int))
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total_blocks = east_blocks(lat_int*1e7, lon_int*1e7) * TERRAIN_GRID_BLOCK_SIZE_Y
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for blocknum in range(total_blocks):
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(lat_e7, lon_e7) = pos_from_file_offset(lat_int, lon_int, blocknum * IO_BLOCK_SIZE)
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lat = lat_e7 * 1.0e-7
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lon = lon_e7 * 1.0e-7
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grid = GridBlock(lat_int, lon_int, lat, lon)
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if grid.blocknum() != blocknum:
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continue
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if not args.force and dfile.check_filled(grid):
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continue
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for gx in range(TERRAIN_GRID_BLOCK_SIZE_X):
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for gy in range(TERRAIN_GRID_BLOCK_SIZE_Y):
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lat_e7, lon_e7 = add_offset(lat*1.0e7, lon*1.0e7, gx*GRID_SPACING, gy*GRID_SPACING)
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lat2_int = int(math.floor(lat_e7*1.0e-7))
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lon2_int = int(math.floor(lon_e7*1.0e-7))
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tile_idx = (lat2_int, lon2_int)
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while not tile_idx in tiles:
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tile = downloader.getTile(lat2_int, lon2_int)
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waited = False
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if tile == 0:
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print("waiting on download of %d,%d" % (lat2_int, lon2_int))
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time.sleep(0.3)
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waited = True
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continue
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if waited:
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print("downloaded %d,%d" % (lat2_int, lon2_int))
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tiles[tile_idx] = tile
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altitude = tiles[tile_idx].getAltitudeFromLatLon(lat_e7*1.0e-7, lon_e7*1.0e-7)
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grid.fill(gx, gy, altitude)
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dfile.write(grid)
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from argparse import ArgumentParser
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parser = ArgumentParser(description='terrain data creator')
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parser.add_argument("lat", type=float, default=-35.363261)
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parser.add_argument("lon", type=float, default=149.165230)
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parser.add_argument("--force", action='store_true', help="overwrite existing full blocks")
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parser.add_argument("--radius", type=int, default=100, help="radius in km")
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parser.add_argument("--debug", action='store_true', default=False)
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parser.add_argument("--spacing", type=int, default=100, help="grid spacing in meters")
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args = parser.parse_args()
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downloader = srtm.SRTMDownloader(debug=args.debug)
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downloader.loadFileList()
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GRID_SPACING = args.spacing
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done = set()
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for dx in range(-args.radius, args.radius):
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for dy in range(-args.radius, args.radius):
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(lat2,lon2) = add_offset(args.lat*1e7, args.lon*1e7, dx*1000.0, dy*1000.0)
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lat_int = int(round(lat2 * 1.0e-7))
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lon_int = int(round(lon2 * 1.0e-7))
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tag = (lat_int, lon_int)
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if tag in done:
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continue
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done.add(tag)
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create_degree(lat_int, lon_int)
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create_degree(args.lat, args.lon)
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