| 1 | #!/usr/bin/env python |
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| 2 | |
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| 3 | # from os import open, write, read |
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| 4 | import Numeric |
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| 5 | |
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| 6 | |
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| 7 | def write_ermapper_header(ofile, datum = 'AGD66', projection = 'GEOGRAPHIC', |
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| 8 | coordinate_type = 'LL', rotation = '0:0:0.0', |
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| 9 | cell_type = 'IEEE4ByteReal', null_value = '-99999', |
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| 10 | x_dim = '100', x_ll = '0:0:0', y_dim = '100', y_ll = '0:0:0', |
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| 11 | num_lines = '3', num_cells = '4', num_bands = '1', |
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| 12 | band_id = 'band1'): |
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| 13 | |
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| 14 | # Determine if the dataset is in lats/longs or eastings/northings and set header parameters |
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| 15 | # accordingly |
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| 16 | if coordinate_type is 'LL': |
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| 17 | X_Class = 'Longitude' |
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| 18 | Y_Class = 'Latitude' |
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| 19 | elif coordinate_type is 'EN': |
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| 20 | X_Class = 'Eastings' |
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| 21 | Y_Class = 'Northings' |
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| 22 | |
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| 23 | # open the header file for writing to |
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| 24 | fid = open(ofile,'wt') |
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| 25 | |
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| 26 | # Begin writing the header |
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| 27 | fid.write('DatasetHeader Begin\n') |
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| 28 | fid.write('\tVersion\t\t\t= "6.4"\n') |
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| 29 | fid.write('\tDatasetType\t\t= ERStorage\n') |
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| 30 | fid.write('\tDataType\t\t= Raster\n') |
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| 31 | fid.write('\tByteOrder\t\t= LSBFirst\n') |
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| 32 | |
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| 33 | # Write the coordinate space information |
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| 34 | fid.write('\tCoordinateSpace Begin\n') |
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| 35 | fid.write('\t\tDatum\t\t\t = "' + datum + '"\n') |
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| 36 | fid.write('\t\tProjection\t\t = "' + projection + '"\n') |
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| 37 | fid.write('\t\tCoordinateType\t = ' + coordinate_type + '\n') |
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| 38 | fid.write('\t\tRotation\t\t = ' + rotation + '\n') |
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| 39 | fid.write('\tCoordinateSpace End\n') |
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| 40 | |
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| 41 | # Write the raster information |
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| 42 | fid.write('\tRasterInfo Begin\n') |
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| 43 | fid.write('\t\tCellType\t\t\t = ' + cell_type + '\n') |
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| 44 | fid.write('\t\tNullCellValue\t\t = ' + null_value + '\n') |
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| 45 | fid.write('\t\tRegistrationCellX\t\t = 0\n') |
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| 46 | fid.write('\t\tRegistrationCellY\t\t = ' + str(int(num_lines) - 1) +'\n') |
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| 47 | # Write the cellsize information |
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| 48 | fid.write('\t\tCellInfo Begin\n') |
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| 49 | fid.write('\t\t\tXDimension\t\t\t = ' + x_dim + '\n') |
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| 50 | fid.write('\t\t\tYDimension\t\t\t = ' + y_dim + '\n') |
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| 51 | fid.write('\t\tCellInfo End\n') |
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| 52 | # Continue with wrting the raster information |
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| 53 | fid.write('\t\tNrOfLines\t\t\t = ' + num_lines + '\n') |
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| 54 | fid.write('\t\tNrOfCellsPerLine\t = ' + num_cells + '\n') |
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| 55 | # Write the registration coordinate information |
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| 56 | fid.write('\t\tRegistrationCoord Begin\n') |
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| 57 | fid.write('\t\t\t' + X_Class + '\t\t\t = ' + x_ll + '\n') |
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| 58 | fid.write('\t\t\t' + Y_Class + '\t\t\t = ' + y_ll + '\n') |
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| 59 | fid.write('\t\tRegistrationCoord End\n') |
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| 60 | # Continue with wrting the raster information |
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| 61 | fid.write('\t\tNrOfBands\t\t\t = ' + num_bands + '\n') |
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| 62 | fid.write('\t\tBandID Begin\n') |
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| 63 | fid.write('\t\t\tValue\t\t\t\t = "' + band_id + '"\n') |
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| 64 | fid.write('\t\tBandID End\n') |
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| 65 | fid.write('\tRasterInfo End\n') |
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| 66 | fid.write('DatasetHeader End\n') |
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| 67 | |
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| 68 | fid.close |
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| 69 | |
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| 70 | |
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| 71 | def write_ermapper_data(grid, ofile, data_format = Numeric.Float32): |
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| 72 | # Convert the array to data_format (default format is Float32) |
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| 73 | grid_as_float = grid.astype(data_format) |
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| 74 | |
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| 75 | # Convert array to a string for writing to output file |
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| 76 | output_string = grid_as_float.tostring() |
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| 77 | |
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| 78 | # open output file in a binary format and write the output string |
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| 79 | fid = open(ofile,'wb') |
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| 80 | fid.write(output_string) |
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| 81 | fid.close() |
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| 82 | |
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| 83 | |
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| 84 | def read_ermapper_data(ifile, data_format = Numeric.Float32): |
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| 85 | # open input file in a binary format and read the input string |
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| 86 | fid = open(ifile,'rb') |
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| 87 | input_string = fid.read() |
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| 88 | fid.close() |
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| 89 | |
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| 90 | # convert input string to required format (Note default format is Numeric.Float32) |
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| 91 | grid_as_float = Numeric.fromstring(input_string,data_format) |
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| 92 | return grid_as_float |
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| 93 | |
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| 94 | def create_default_header(header): |
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| 95 | # fill any blanks in a header dictionary with default values |
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| 96 | # input parameters: |
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| 97 | # header: a dictionary containing fields that are not meant |
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| 98 | # to be filled with default values |
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| 99 | |
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| 100 | ## projection = 'GEOGRAPHIC', |
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| 101 | ## coordinate_type = 'LL', rotation = '0:0:0.0', |
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| 102 | ## cell_type = 'IEEE4ByteReal', null_value = '-99999', |
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| 103 | ## x_dim = '100', x_ll = '0:0:0', y_dim = '100', y_ll = '0:0:0', |
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| 104 | ## num_lines = '3', num_cells = '4', num_bands = '1', |
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| 105 | ## band_id = 'band1') |
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| 106 | if not header.has_key('datum'): |
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| 107 | header['datum'] = 'GDA94' |
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| 108 | if not header.has_key('projection'): |
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| 109 | header['datum'] = 'GEOGRAPHIC' |
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| 110 | |
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| 111 | return header |
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| 116 | |
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