Convert from simple binary format to ArcAscii - based on https://gist.github.com/nikmolnar/284b5541bfc54946a24b

get_ascii.py

__author__ = 'Taylor'
'''
    Convert binary format to ArcAscii Format - adapted from https://gist.github.com/nikmolnar/284b5541bfc54946a24b
'''


import os, struct, sys, math, requests

server = 'your/terrain/server/here' # Ask for the URL if you want to try it out.


def main():
    if len(sys.argv) < 2:
        print('Usage: get_ascii.py <terrainName>.asc')
        sys.exit(-1)

    output_path = sys.argv[1]
    if os.path.exists(output_path):
        overwrite_message = '{0} already exists. Overwrite? [y/n] '.format(output_path)
        if not input(overwrite_message).lower().startswith('y'):
            sys.exit(-1)

    lat1 = float(input('South: '))
    lat2 = float(input('North: '))
    lng1 = float(input('East: '))
    lng2 = float(input('West: '))
    width = int(input('Number of segments: '))
    height = int(input('Number of latitude segments (-1 for equal aspect ratio): '))

    if (height == -1):
        payload = {'lat1': str(lat1),
                   'lat2': str(lat2),
                   'lng1': str(lng1),
                   'lng2': str(lng2),
                   'numlngs': str(width)}
    else:
        payload = {'lat1': str(lat1),
                   'lat2': str(lat2),
                   'lng1': str(lng1),
                   'lng2': str(lng2),
                   'numlats': str(height),
                   'numlngs': str(width)}

    try:
        r = requests.get(server, params=payload)
        print(r.content)
        print('Request successful, writing to ' + output_path + '\n')
    except requests.HTTPError:
        print('Request failed... a team of highly trained monkeys is on its way!')
        sys.exit(-1)

    if (height == -1): # Get the correct number of latitudes from the server
        form_feed = b'\x0c'
        index = 0
        myChar = b''
        while myChar != form_feed:
            myChar = r.content[index:index+1]
            if myChar == form_feed:
                break
            index +=1
        height = int(r.content[:index].decode('ascii').split()[5]) # this is the right position for height

    with open(output_path, 'w') as f_out:

        header = [
            'ncols {0}'.format(width),
            'nrows {0}'.format(height),
            'xllcorner 0.0',
            'yllcorner 0.0',
            'cellsize 1.0',
            'NODATA_value -9999',
            ''
        ]
        f_out.write('\n'.join(header))
        index = 0
        for i in range(1, height + 1):
            index = len(r.content) - i*4*width  # floats are 4 bytes long
            floats = struct.unpack('f' * width, r.content[index: index + 4*width])
            line = (str(x) for x in floats)
            f_out.write(' '.join(line) + '\n')

if __name__ == '__main__':
    main()