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3 | <TITLE>Survex 3d Format Specification</TITLE> |
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9 | .type {text-align: center; white-space: nowrap;} |
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10 | .data {text-align: left; white-space: nowrap;} |
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11 | .desc {text-align: left; white-space: wrap;} |
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12 | .version {text-align: center; white-space: wrap;} |
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16 | </STYLE> |
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17 | </HEAD><BODY BGCOLOR=white TEXT=black> |
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18 | <H1>Survex 3d Format Specification</H1> |
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19 | |
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20 | <P>If you're writing in C or C++ it's <b>strongly</b> recommended |
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21 | that you use the img routine provided with Survex to read and write |
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22 | 3d files. Doing so means that you can take advantage of any revisions |
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23 | to the 3d format by simply rebuilding your software with the updated |
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24 | img routines, rather than having to update your own code. It also |
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25 | allows you to read a sub-set of the data in the file, restricted by |
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26 | Survey prefix.</P> |
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27 | |
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28 | <P>This document only describes the more recent revisions of the 3d format |
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29 | (versions 3 to 7, inclusive). |
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30 | Version 3 was produced by Survex versions 0.97 and later, |
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31 | version 4 by Survex 1.1.0-1.1.3, |
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32 | version 5 by 1.1.4-1.1.10, |
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33 | version 6 by 1.1.11-1.1.14, |
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34 | and version 7 by versions from 1.1.15.</P> |
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35 | |
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36 | <P>If you try to use this specification and find details which aren't |
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37 | spelled out clearly enough (or at all!) or any errors, please let us know. |
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38 | At least two people have successfully written code to read 3d files |
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39 | using this document, but that doesn't mean it can't be improved. |
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40 | </P> |
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41 | |
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42 | <H2>File Header</H2> |
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43 | |
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44 | <P>This consists of:</P> |
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45 | |
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46 | <ul> |
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47 | <li>File ID: the string "Survex 3D Image File" followed by a linefeed |
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48 | (decimal 10, hex x0a). [Note: v0.01 files can have a carriage return |
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49 | before this and other linefeeds - this is a file format error in any |
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50 | other format version]. |
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51 | <li>File format version: "v3", "v4", etc followed by a linefeed. |
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52 | If the format gets to version 10, that would be "v10". |
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53 | Older format versions aren't described here, but had version strings |
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54 | "v0.01", "Bv0.01", "bv0.01", and "v2"). |
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55 | <li> Survey title: A string followed by a linefeed. There's no length limit on this string. |
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56 | <li> Timestamp: A string followed by a linefeed. This is intended to be the |
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57 | time the file was generated, rather than the time the survey data was |
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58 | collected. The easiest way to generate this is with the strftime() format |
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59 | "%a,%Y.%m.%d %H:%M:%S %Z" if you have access to strftime(). An example |
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60 | timestamp is "Sun,2002.03.17 14:01:07 GMT". |
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61 | </ul> |
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62 | |
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63 | <H2>Items</H2> |
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64 | |
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65 | <P>Following the header are a number of items. The last item must be a 0x00 |
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66 | byte when the current label is empty, which marks the end of the data. The |
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67 | first byte of an item is a code identifying what the item is:</P> |
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68 | |
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69 | <table border="1" cellpadding="1" cellspacing="0" width="100%"> |
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70 | <tr> |
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71 | <th class="code">Code</th> |
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72 | <th class="code">Type</th> |
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73 | <th class="data">Data</th> |
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74 | <th class="desc" colspan="2">Meaning</th> |
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75 | <th class="version">Version</th> |
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76 | </tr> |
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77 | <tr> |
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78 | <td class="code">0x00</td> |
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79 | <td class="type">STOP</td> |
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80 | <td class="data"> </td> |
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81 | <td class="desc" colspan="2"> |
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82 | If the current label is empty, signifies the end of the data in the 3d |
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83 | file; if the current label isn't empty, make it empty.</td> |
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84 | <td class="version">≥3</td> |
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85 | </tr> |
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86 | <tr> |
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87 | <td class="code">0x01 - 0x0e</td> |
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88 | <td class="type">TRIM</td> |
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89 | <td class="data"> </td> |
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90 | <td class="desc" colspan="2"> |
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91 | Trim the last 16 characters of the current label, then trim back N (i.e. |
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92 | 1-14) dots ("."), everything after that particular dot. |
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93 | It's incorrect if the label ends up empty, or you attempt to trim more |
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94 | label than there is. The rationale for removing 16 characters first is |
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95 | that removal of 1-16 characters can be encoded by 0x10-0x1f (see below) |
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96 | and we can make this encoding more powerful by not |
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97 | overlapping what can be encoded.</td> |
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98 | <td class="version">≥3</td> |
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99 | </tr> |
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100 | <tr> |
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101 | <td class="code">0x0f</td> |
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102 | <td class="type">MOVE</td> |
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103 | <td class="data"><x> <y> <z></td> |
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104 | <td class="desc" colspan="2"> |
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105 | Set current position to the coordinates given. Coordinates |
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106 | are 4 byte little-endian signed integers representing |
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107 | values in centimetres (0.01 metres).</td> |
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108 | <td class="version">≥3</td> |
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109 | </tr> |
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110 | <tr> |
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111 | <td class="code">0x10 - 0x1f</td> |
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112 | <td class="type">TRIM</td> |
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113 | <td class="data"> </td> |
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114 | <td colspan="2"> |
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115 | Remove N-15 (i.e. 1-16) characters from the current label. It's |
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116 | incorrect if the label ends up empty, or you attempt to trim more label |
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117 | than there is.</td> |
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118 | <td class="version">≥3</td> |
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119 | </tr> |
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120 | <tr> |
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121 | <td class="code">0x20</td> |
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122 | <td class="type">DATE (old version)</td> |
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123 | <td class="data"><date></td> |
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124 | <td colspan="2"> |
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125 | Set survey date of legs (date is 4 byte little endian unsigned integer |
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126 | counting seconds since 1970) </td> |
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127 | <td class="version">≥4 and ≤6</td> |
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128 | </tr> |
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129 | <tr> |
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130 | <td class="code">0x20</td> |
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131 | <td class="type">DATE</td> |
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132 | <td class="data"><date></td> |
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133 | <td colspan="2"> |
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134 | Set survey date of legs (date is |
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135 | 2 byte unsigned integer counting days since the |
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136 | start of 1900)</td> |
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137 | <td class="version">≥7</td> |
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138 | </tr> |
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139 | <tr> |
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140 | <td class="code">0x21</td> |
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141 | <td class="type">DATE (old version)</td> |
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142 | <td class="data"><date1><date2></td> |
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143 | <td colspan="2"> |
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144 | Set survey date of legs to a range (date1, date2 are 4 byte little |
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145 | endian unsigned integer counting seconds since 1970) </td> |
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146 | <td class="version">≥4 and ≤6</td> |
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147 | </tr> |
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148 | <tr> |
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149 | <td class="code">0x21</td> |
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150 | <td class="type">DATE</td> |
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151 | <td class="data"><date1><datespan></td> |
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152 | <td colspan="2"> |
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153 | Set survey date of legs to a range (date1 is a |
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154 | 2 byte unsigned integer counting days since the |
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155 | start of 1900, datespan is an unsigned byte storing date2-date1-1)</td> |
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156 | <td class="version">≥7</td> |
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157 | </tr> |
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158 | <tr> |
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159 | <td class="code">0x22</td> |
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160 | <td class="type">ERROR</td> |
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161 | <td class="data"><legs><length><E><H><V></td> |
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162 | <td colspan="2"> |
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163 | Error information for the current traverse. <legs> is the number of legs. <length> is the total length of the |
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164 | traverse in cm (0.01m). E, H and V are the error and thehorizontal and vertical components in cm. (All values are 4 byte little |
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165 | endian signed integers) </td> |
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166 | <td class="version">≥6</td> |
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167 | </tr> |
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168 | <tr> |
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169 | <td class="code">0x23</td> |
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170 | <td class="type">DATE</td> |
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171 | <td class="data"><date1><date2></td> |
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172 | <td colspan="2"> |
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173 | Set survey date of legs to a range (date1, date2 are |
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174 | 2 byte unsigned integers counting days since the |
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175 | start of 1900)</td> |
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176 | <td class="version">≥7</td> |
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177 | </tr> |
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178 | <tr> |
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179 | <td class="code">0x24</td> |
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180 | <td class="type">DATE</td> |
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181 | <td class="data"> </td> |
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182 | <td colspan="2"> |
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183 | Seet survey date to "no date information"</td> |
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184 | <td class="version">≥7</td> |
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185 | </tr> |
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186 | <tr class="reserved"> |
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187 | <td class="code">0x25 - 0x2f</td> |
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188 | <td class="type"> </td> |
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189 | <td class="data"> </td> |
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190 | <td colspan="3">Reserved</td> |
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191 | </tr> |
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192 | <tr> |
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193 | <td class="code" rowspan="3">0x30 - 0x31</td> |
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194 | <td class="type" rowspan="3">XSECT</td> |
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195 | <td class="data" rowspan="3"><len> <label> <L> <R> <U> <D></td> |
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196 | <td colspan="2"> |
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197 | Dimensions are 2 byte little-endian signed integers representing values |
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198 | in centimetres (0.01 metres). Omitted dimensions are encoded as 0xffff. |
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199 | Station flags are (N & 0x01): </td> |
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200 | <td class="version" rowspan="3">≥5</td> |
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201 | </tr> |
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202 | <tr> |
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203 | <th>Flag (N & 0x01)</th> |
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204 | <th>Meaning</th> |
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205 | </tr> |
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206 | <tr> |
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207 | <td>0x01</td> |
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208 | <td>Station is last one in this passage</td> |
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209 | </tr> |
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210 | <tr> |
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211 | <td class="code" rowspan="3">0x32 - 0x33</td> |
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212 | <td class="type" rowspan="3">XSECT</td> |
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213 | <td class="data" rowspan="3"><len> <label> <L> <R> <U> <D></td> |
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214 | <td colspan="2"> |
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215 | Dimensions are 4 byte little-endian signed integers representing values |
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216 | in centimetres (0.01 metres). Omitted dimensions are encoded as |
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217 | 0xffffffff.</td> |
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218 | <td class="version" rowspan="3">≥5</td> |
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219 | </tr> |
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220 | <tr> |
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221 | <th>Flag (N & 0x01)</th> |
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222 | <th>Meaning</th> |
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223 | </tr> |
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224 | <tr> |
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225 | <td>0x01</td> |
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226 | <td>Station is last one in this passage</td> |
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227 | </tr> |
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228 | <tr class="reserved"> |
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229 | <td class="code">0x34 - 0x3f</td> |
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230 | <td class="type"> </td> |
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231 | <td class="data"> </td> |
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232 | <td colspan="3">Reserved</td> |
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233 | </tr> |
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234 | <!-- Checked to here! --> |
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235 | <tr> |
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236 | <td class="code" rowspan="13">0x40 - 0x7f</td> |
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237 | <td class="type" rowspan="13">LABEL</td> |
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238 | <td class="data" rowspan="13"><len> <label> <x> <y> <z></td> |
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239 | <td colspan="2"> |
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240 | Append label to the current label buffer. The updated contents of the |
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241 | label buffer give the survey stations full name. The length of label is |
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242 | given by length, which is encoded as follows:</td> |
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243 | <td class="version" rowspan="12">≥3</td> |
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244 | </tr> |
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245 | <tr> |
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246 | <th>Length</th> |
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247 | <th>Encoding</th> |
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248 | </tr> |
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249 | <tr> |
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250 | <td>0 - 253</td> |
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251 | <td>byte 0x00 - 0xfd</td> |
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252 | </tr> |
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253 | <tr> |
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254 | <td>254-65789</td> |
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255 | <td>byte 0xfe 2 byte little-endian unsigned integer len-254 0x0000-0xffff</td> |
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256 | </tr> |
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257 | <tr> |
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258 | <td>65790 and greater</td> |
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259 | <td>byte 0xff 4 byte little-endian unsigned integer len |
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260 | 0x000100fd-0xffffffff</td> |
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261 | </tr> |
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262 | <tr> |
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263 | <td colspan="2"> |
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264 | The station flags are encoded in the bottom 6 bits of the item code:</td> |
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265 | </tr> |
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266 | <tr> |
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267 | <th>Flag (N & 0x3f)</th> |
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268 | <th>Meaning</th> |
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269 | </tr> |
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270 | <tr> |
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271 | <td>0x01</td> |
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272 | <td>Station is on leg above ground</td> |
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273 | </tr> |
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274 | <tr> |
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275 | <td>0x02</td> |
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276 | <td>Station is on an underground leg (both may be true at an entrance)</td> |
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277 | </tr> |
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278 | <tr> |
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279 | <td>0x04</td> |
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280 | <td>Station is marked as an entrance (with *entrance)</td> |
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281 | </tr> |
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282 | <tr> |
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283 | <td>0x08</td> |
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284 | <td>Station is exported (i.e. may be used as a connection point to other |
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285 | surveys)</td> |
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286 | </tr> |
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287 | <tr> |
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288 | <td>0x10</td> |
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289 | <td>Station is a fixed point (control point)</td> |
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290 | </tr> |
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291 | <tr class="reserved"> |
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292 | <td>0x20</td> |
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293 | <td colspan="2">Reserved</td> |
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294 | </tr> |
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295 | <tr> |
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296 | <td class="code" rowspan="8">0x80 - 0xbf</td> |
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297 | <td class="type" rowspan="8">LINE</td> |
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298 | <td class="data" rowspan="8"><len> <label> <x> <y> <z></td> |
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299 | <td colspan="2"> |
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300 | Append label to the current label buffer. The length of the label is |
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301 | encoded as for a station label above. Return leg from current position |
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302 | to coordinates given, and update current position to coordinates given. |
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303 | The updated contents of the label buffer give the survey that the leg is |
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304 | in.</td> |
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305 | <td class="version" rowspan="5">≥3</td> |
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306 | </tr> |
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307 | <tr> |
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308 | <th>Flag (N & 0x3f)</th> |
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309 | <th>Meaning</th> |
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310 | </tr> |
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311 | <tr> |
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312 | <td>0x01</td> |
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313 | <td>Leg is above ground</td> |
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314 | </tr> |
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315 | <tr> |
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316 | <td>0x02</td> |
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317 | <td>Leg duplicates data in another leg (e.g. resurvey along a passage to |
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318 | tie into a known station)</td> |
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319 | </tr> |
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320 | <tr> |
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321 | <td>0x04</td> |
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322 | <td>Leg is a splay shot in a chamber (radial shots from a central point)</td> |
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323 | </tr> |
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324 | <tr class="reserved"> |
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325 | <td>0x08</td> |
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326 | <td colspan="2">Reserved</td> |
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327 | </tr> |
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328 | <tr class="reserved"> |
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329 | <td>0x10</td> |
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330 | <td colspan="2">Reserved</td> |
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331 | </tr> |
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332 | <tr class="reserved"> |
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333 | <td>0x20</td> |
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334 | <td colspan="2">Reserved</td> |
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335 | </tr> |
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336 | <tr class="reserved"> |
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337 | <td class="code">0xc0 - 0xff</td> |
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338 | <td class="type"> </td> |
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339 | <td class="data"> </td> |
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340 | <td colspan="3">Reserved</td> |
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341 | </tr> |
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342 | </table> |
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343 | |
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344 | <H2>Item order</H2> |
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345 | <ul> |
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346 | <li>A continuous section of centreline is defined by a <MOVE> item, followed |
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347 | by one or more <LINE> items.</li> |
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348 | <li><LABEL> items may appear anywhere in the file after the header, |
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349 | including within a <MOVE><LINE>... sequence.</li> |
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350 | <li>Duplicate <LABEL> items are permitted provided they also have identical |
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351 | coordinate values. (The same coordinate values may also be shared by any |
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352 | number of different <LABEL> items).</li> |
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353 | <li>Stations must be defined in a <LABEL> item <u>before</u> being |
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354 | referenced (e.g. in <XSECT> items)</li> |
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355 | </ul> |
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356 | |
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357 | <P>Authors: Olly Betts and Mike McCombe, last updated: 2010-08-18</P> |
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358 | </BODY></HTML> |
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