| 1 | <!DOCTYPE HTML PUBLIC "-//W4C//DTD HTML 4.0 Transitional//EN"> |
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| 2 | <HTML><HEAD> |
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| 3 | <TITLE>Survex 3d Format Specification (v3-v7)</TITLE> |
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| 8 | .code {text-align: center; white-space: nowrap;} |
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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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| 13 | TH.data, TH.desc {text-align: center;} |
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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 (v3-v7)</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 other processed survey data formats (those from |
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| 26 | Larry Fish's Compass and from Bob Thrun's CMAP), and allows reading |
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| 27 | a sub-set of the data in a file, restricted by survey prefix.</P> |
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| 28 | |
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| 29 | <P>This document only describes 3d format revisions 3 to 7 (inclusive). |
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| 30 | Newer versions are described in a <a href="3dformat.htm">separate document</a>. |
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| 31 | Older format versions are only documented by the code to read them in img.c - |
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| 32 | they had version strings "v0.01", "Bv0.01", "bv0.01", and "v2"). |
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| 33 | </P> |
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| 34 | |
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| 35 | <P>The following table document which Survex versions generate which 3d file |
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| 36 | format versions. A version is able to read the format it generates and any |
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| 37 | older versions, but in addition Survex 1.0.40 has support for reading all |
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| 38 | versions up to v7 (but writes v3). |
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| 39 | |
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| 40 | <table border="1" cellpadding="1" cellspacing="0" width="*"> |
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| 41 | <tr> |
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| 42 | <th class="version">Format</th> |
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| 43 | <th class="version" colspan=2>Survex versions</th> |
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| 44 | </tr> |
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| 45 | <tr> |
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| 46 | <td class="version">v3</td> |
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| 47 | <td class="version">0.97</td> |
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| 48 | <td class="version">1.0.40</td> |
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| 49 | </tr> |
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| 50 | <tr> |
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| 51 | <td class="version">v4</td> |
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| 52 | <td class="version">1.1.0</td> |
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| 53 | <td class="version">1.1.3</td> |
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| 54 | </tr> |
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| 55 | <tr> |
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| 56 | <td class="version">v5</td> |
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| 57 | <td class="version">1.1.4</td> |
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| 58 | <td class="version">1.1.10</td> |
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| 59 | </tr> |
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| 60 | <tr> |
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| 61 | <td class="version">v6</td> |
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| 62 | <td class="version">1.1.11</td> |
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| 63 | <td class="version">1.1.14</td> |
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| 64 | </tr> |
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| 65 | <tr> |
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| 66 | <td class="version">v7</td> |
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| 67 | <td class="version">1.1.15</td> |
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| 68 | <td class="version">1.2.6</td> |
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| 69 | </tr> |
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| 70 | </table> |
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| 71 | |
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| 72 | <P>If you try to use this specification and find details which aren't |
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| 73 | spelled out clearly enough (or at all!) or any errors, please let us know. |
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| 74 | At least two people have successfully written code to read 3d files |
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| 75 | using this document, but that doesn't mean it can't be improved. |
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| 76 | </P> |
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| 77 | |
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| 78 | <H2>File Header</H2> |
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| 79 | |
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| 80 | <P>This consists of:</P> |
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| 81 | |
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| 82 | <ul> |
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| 83 | <li>File ID: the string "Survex 3D Image File" followed by a linefeed |
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| 84 | (decimal 10, hex 0a). [Note: v0.01 files can have a carriage return |
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| 85 | before this and other linefeeds - this is a file format error in any |
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| 86 | other format version]. |
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| 87 | <li>File format version: "v3", "v4", "v5", "v6", "v7" followed by a linefeed. |
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| 88 | Any future versions will be "v8", "v9", "v10", "v11", etc. |
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| 89 | <li> Survey title: A string followed by a linefeed. There's no length limit on this string. |
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| 90 | <li> Timestamp: A string followed by a linefeed. This is intended to be the |
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| 91 | time the file was generated, rather than the time the survey data was |
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| 92 | collected. The easiest way to generate this is with the strftime() format |
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| 93 | "%a,%Y.%m.%d %H:%M:%S %Z" if you have access to strftime(). An example |
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| 94 | timestamp is "Sun,2002.03.17 14:01:07 GMT". |
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| 95 | </ul> |
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| 96 | |
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| 97 | <H2>Items</H2> |
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| 98 | |
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| 99 | <P>Following the header are a number of items. The last item must be a 0x00 |
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| 100 | byte when the current label is empty, which marks the end of the data. The |
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| 101 | first byte of an item is a code identifying what the item is:</P> |
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| 102 | |
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| 103 | <table border="1" cellpadding="1" cellspacing="0" width="100%"> |
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| 104 | <tr> |
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| 105 | <th class="code">Code</th> |
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| 106 | <th class="code">Type</th> |
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| 107 | <th class="data">Data</th> |
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| 108 | <th class="desc" colspan="2">Meaning</th> |
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| 109 | <th class="version">Version</th> |
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| 110 | </tr> |
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| 111 | <tr> |
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| 112 | <td class="code">0x00</td> |
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| 113 | <td class="type">STOP</td> |
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| 114 | <td class="data"> </td> |
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| 115 | <td class="desc" colspan="2"> |
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| 116 | If the current label is empty, signifies the end of the data in the 3d |
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| 117 | file; if the current label isn't empty, make it empty.</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">0x01 - 0x0e</td> |
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| 122 | <td class="type">TRIM</td> |
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| 123 | <td class="data"> </td> |
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| 124 | <td class="desc" colspan="2"> |
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| 125 | Trim the last 16 characters of the current label, then trim back N (i.e. |
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| 126 | 1-14) dots ("."), everything after that particular dot. |
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| 127 | It's incorrect if the label ends up empty, or you attempt to trim more |
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| 128 | label than there is. The rationale for removing 16 characters first is |
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| 129 | that removal of 1-16 characters can be encoded by 0x10-0x1f (see below) |
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| 130 | and we can make this encoding more powerful by not |
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| 131 | overlapping what can be encoded.</td> |
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| 132 | <td class="version">≥3</td> |
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| 133 | </tr> |
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| 134 | <tr> |
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| 135 | <td class="code">0x0f</td> |
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| 136 | <td class="type">MOVE</td> |
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| 137 | <td class="data"><x> <y> <z></td> |
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| 138 | <td class="desc" colspan="2"> |
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| 139 | Set current position to the coordinates given. Coordinates |
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| 140 | are 4 byte little-endian signed integers representing |
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| 141 | values in centimetres (0.01 metres).</td> |
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| 142 | <td class="version">≥3</td> |
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| 143 | </tr> |
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| 144 | <tr> |
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| 145 | <td class="code">0x10 - 0x1f</td> |
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| 146 | <td class="type">TRIM</td> |
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| 147 | <td class="data"> </td> |
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| 148 | <td colspan="2"> |
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| 149 | Remove N-15 (i.e. 1-16) characters from the current label. It's |
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| 150 | incorrect if the label ends up empty, or you attempt to trim more label |
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| 151 | than there is.</td> |
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| 152 | <td class="version">≥3</td> |
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| 153 | </tr> |
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| 154 | <tr> |
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| 155 | <td class="code">0x20</td> |
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| 156 | <td class="type">DATE (old version)</td> |
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| 157 | <td class="data"><date></td> |
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| 158 | <td colspan="2"> |
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| 159 | Set survey date of legs: date is 4 byte little-endian unsigned integer |
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| 160 | counting seconds since 1970.</td> |
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| 161 | <td class="version">≥4 and ≤6</td> |
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| 162 | </tr> |
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| 163 | <tr> |
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| 164 | <td class="code">0x20</td> |
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| 165 | <td class="type">DATE</td> |
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| 166 | <td class="data"><date></td> |
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| 167 | <td colspan="2"> |
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| 168 | Set survey date of legs: date is a 2 byte little-endian unsigned integer |
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| 169 | counting days from the |
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| 170 | start of 1900.</td> |
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| 171 | <td class="version">≥7</td> |
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| 172 | </tr> |
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| 173 | <tr> |
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| 174 | <td class="code">0x21</td> |
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| 175 | <td class="type">DATE (old version)</td> |
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| 176 | <td class="data"><date1><date2></td> |
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| 177 | <td colspan="2"> |
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| 178 | Set survey date of legs to a range: date1, date2 are 4 byte little-endian |
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| 179 | unsigned integer counting seconds since 1970.</td> |
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| 180 | <td class="version">≥4 and ≤6</td> |
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| 181 | </tr> |
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| 182 | <tr> |
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| 183 | <td class="code">0x21</td> |
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| 184 | <td class="type">DATE</td> |
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| 185 | <td class="data"><date1><datespan></td> |
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| 186 | <td colspan="2"> |
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| 187 | Set survey date of legs to a range: date1 is a |
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| 188 | 2 byte little-endian unsigned integer counting days since the start of |
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| 189 | 1900, and datespan is an unsigned byte counting days from date1.</td> |
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| 190 | <td class="version">≥7</td> |
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| 191 | </tr> |
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| 192 | <tr> |
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| 193 | <td class="code">0x22</td> |
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| 194 | <td class="type">ERROR</td> |
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| 195 | <td class="data"><legs><length><E><H><V></td> |
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| 196 | <td colspan="2"> |
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| 197 | Error information for the current traverse. <legs> is the number of |
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| 198 | legs. <length> is the total length of the |
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| 199 | traverse in cm (0.01m). E, H and V are the error and the horizontal and |
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| 200 | vertical components in cm. (All values are 4 byte little-endian signed integers) </td> |
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| 201 | <td class="version">≥6</td> |
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| 202 | </tr> |
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| 203 | <tr> |
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| 204 | <td class="code">0x23</td> |
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| 205 | <td class="type">DATE</td> |
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| 206 | <td class="data"><date1><date2></td> |
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| 207 | <td colspan="2"> |
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| 208 | Set survey date of legs to a range: date1, date2 are |
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| 209 | 2 byte little-endian unsigned integers counting days since the |
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| 210 | start of 1900.</td> |
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| 211 | <td class="version">≥7</td> |
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| 212 | </tr> |
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| 213 | <tr> |
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| 214 | <td class="code">0x24</td> |
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| 215 | <td class="type">DATE</td> |
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| 216 | <td class="data"> </td> |
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| 217 | <td colspan="2"> |
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| 218 | No survey date information was specified.</td> |
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| 219 | <td class="version">≥7</td> |
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| 220 | </tr> |
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| 221 | <tr class="reserved"> |
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| 222 | <td class="code">0x25 - 0x2f</td> |
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| 223 | <td class="type"> </td> |
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| 224 | <td class="data"> </td> |
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| 225 | <td colspan="3">Reserved</td> |
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| 226 | </tr> |
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| 227 | <tr> |
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| 228 | <td class="code" rowspan="3">0x30 - 0x31</td> |
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| 229 | <td class="type" rowspan="3">XSECT</td> |
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| 230 | <td class="data" rowspan="3"><len> <label> <L> <R> <U> <D></td> |
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| 231 | <td colspan="2"> |
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| 232 | Dimensions are 2 byte little-endian signed integers representing values |
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| 233 | in centimetres (0.01 metres). Omitted dimensions are encoded as 0xffff. |
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| 234 | Station flags are (N & 0x01): </td> |
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| 235 | <td class="version" rowspan="3">≥5</td> |
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| 236 | </tr> |
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| 237 | <tr> |
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| 238 | <th>Flag (N & 0x01)</th> |
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| 239 | <th>Meaning</th> |
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| 240 | </tr> |
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| 241 | <tr> |
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| 242 | <td>0x01</td> |
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| 243 | <td>Station is last one in this passage</td> |
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| 244 | </tr> |
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| 245 | <tr> |
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| 246 | <td class="code" rowspan="3">0x32 - 0x33</td> |
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| 247 | <td class="type" rowspan="3">XSECT</td> |
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| 248 | <td class="data" rowspan="3"><len> <label> <L> <R> <U> <D></td> |
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| 249 | <td colspan="2"> |
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| 250 | Dimensions are 4 byte little-endian signed integers representing values |
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| 251 | in centimetres (0.01 metres). Omitted dimensions are encoded as |
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| 252 | 0xffffffff.</td> |
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| 253 | <td class="version" rowspan="3">≥5</td> |
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| 254 | </tr> |
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| 255 | <tr> |
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| 256 | <th>Flag (N & 0x01)</th> |
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| 257 | <th>Meaning</th> |
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| 258 | </tr> |
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| 259 | <tr> |
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| 260 | <td>0x01</td> |
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| 261 | <td>Station is last one in this passage</td> |
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| 262 | </tr> |
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| 263 | <tr class="reserved"> |
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| 264 | <td class="code">0x34 - 0x3f</td> |
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| 265 | <td class="type"> </td> |
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| 266 | <td class="data"> </td> |
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| 267 | <td colspan="3">Reserved</td> |
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| 268 | </tr> |
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| 269 | <!-- Checked to here! --> |
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| 270 | <tr> |
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| 271 | <td class="code" rowspan="13">0x40 - 0x7f</td> |
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| 272 | <td class="type" rowspan="13">LABEL</td> |
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| 273 | <td class="data" rowspan="13"><len> <label> <x> <y> <z></td> |
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| 274 | <td colspan="2"> |
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| 275 | Append label to the current label buffer. The updated contents of the |
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| 276 | label buffer give the survey stations full name. The length of label is |
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| 277 | given by length, which is encoded as follows:</td> |
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| 278 | <td class="version" rowspan="12">≥3</td> |
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| 279 | </tr> |
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| 280 | <tr> |
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| 281 | <th>Length</th> |
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| 282 | <th>Encoding</th> |
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| 283 | </tr> |
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| 284 | <tr> |
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| 285 | <td>0 - 253</td> |
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| 286 | <td>byte 0x00 - 0xfd</td> |
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| 287 | </tr> |
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| 288 | <tr> |
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| 289 | <td>254-65789</td> |
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| 290 | <td>byte 0xfe 2 byte little-endian unsigned integer len-254 0x0000-0xffff</td> |
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| 291 | </tr> |
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| 292 | <tr> |
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| 293 | <td>65790 and greater</td> |
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| 294 | <td>byte 0xff 4 byte little-endian unsigned integer len |
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| 295 | 0x000100fd-0xffffffff</td> |
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| 296 | </tr> |
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| 297 | <tr> |
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| 298 | <td colspan="2"> |
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| 299 | The station flags are encoded in the bottom 6 bits of the item code:</td> |
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| 300 | </tr> |
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| 301 | <tr> |
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| 302 | <th>Flag (N & 0x3f)</th> |
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| 303 | <th>Meaning</th> |
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| 304 | </tr> |
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| 305 | <tr> |
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| 306 | <td>0x01</td> |
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| 307 | <td>Station is on leg above ground</td> |
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| 308 | </tr> |
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| 309 | <tr> |
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| 310 | <td>0x02</td> |
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| 311 | <td>Station is on an underground leg (both may be true at an entrance)</td> |
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| 312 | </tr> |
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| 313 | <tr> |
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| 314 | <td>0x04</td> |
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| 315 | <td>Station is marked as an entrance (with *entrance)</td> |
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| 316 | </tr> |
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| 317 | <tr> |
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| 318 | <td>0x08</td> |
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| 319 | <td>Station is exported (i.e. may be used as a connection point to other |
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| 320 | surveys)</td> |
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| 321 | </tr> |
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| 322 | <tr> |
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| 323 | <td>0x10</td> |
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| 324 | <td>Station is a fixed point (control point)</td> |
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| 325 | </tr> |
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| 326 | <tr class="reserved"> |
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| 327 | <td>0x20</td> |
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| 328 | <td colspan="2">Reserved</td> |
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| 329 | </tr> |
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| 330 | <tr> |
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| 331 | <td class="code" rowspan="8">0x80 - 0xbf</td> |
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| 332 | <td class="type" rowspan="8">LINE</td> |
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| 333 | <td class="data" rowspan="8"><len> <label> <x> <y> <z></td> |
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| 334 | <td colspan="2"> |
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| 335 | Append label to the current label buffer. The length of the label is |
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| 336 | encoded as for a station label above. Return leg from current position |
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| 337 | to coordinates given, and update current position to coordinates given. |
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| 338 | The updated contents of the label buffer give the survey that the leg is |
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| 339 | in.</td> |
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| 340 | <td class="version" rowspan="5">≥3</td> |
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| 341 | </tr> |
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| 342 | <tr> |
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| 343 | <th>Flag (N & 0x3f)</th> |
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| 344 | <th>Meaning</th> |
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| 345 | </tr> |
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| 346 | <tr> |
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| 347 | <td>0x01</td> |
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| 348 | <td>Leg is above ground</td> |
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| 349 | </tr> |
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| 350 | <tr> |
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| 351 | <td>0x02</td> |
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| 352 | <td>Leg duplicates data in another leg (e.g. resurvey along a passage to |
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| 353 | tie into a known station)</td> |
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| 354 | </tr> |
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| 355 | <tr> |
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| 356 | <td>0x04</td> |
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| 357 | <td>Leg is a splay shot in a chamber (radial shots from a central point)</td> |
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| 358 | </tr> |
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| 359 | <tr class="reserved"> |
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| 360 | <td>0x08</td> |
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| 361 | <td colspan="2">Reserved</td> |
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| 362 | </tr> |
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| 363 | <tr class="reserved"> |
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| 364 | <td>0x10</td> |
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| 365 | <td colspan="2">Reserved</td> |
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| 366 | </tr> |
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| 367 | <tr class="reserved"> |
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| 368 | <td>0x20</td> |
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| 369 | <td colspan="2">Reserved</td> |
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| 370 | </tr> |
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| 371 | <tr class="reserved"> |
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| 372 | <td class="code">0xc0 - 0xff</td> |
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| 373 | <td class="type"> </td> |
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| 374 | <td class="data"> </td> |
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| 375 | <td colspan="3">Reserved</td> |
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| 376 | </tr> |
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| 377 | </table> |
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| 378 | |
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| 379 | <H2>Item order</H2> |
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| 380 | <ul> |
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| 381 | <li>A continuous section of centreline is defined by a <MOVE> item, followed |
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| 382 | by one or more <LINE> items.</li> |
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| 383 | <li><LABEL> items may appear anywhere in the file after the header, |
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| 384 | including within a <MOVE><LINE>... sequence.</li> |
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| 385 | <li>Duplicate <LABEL> items are permitted provided they also have identical |
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| 386 | coordinate values. (The same coordinate values may also be shared by any |
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| 387 | number of different <LABEL> items).</li> |
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| 388 | <li>Stations must be defined in a <LABEL> item <u>before</u> being |
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| 389 | referenced (e.g. in <XSECT> items)</li> |
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| 390 | </ul> |
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| 391 | |
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| 392 | <P>Authors: Olly Betts and Mike McCombe, last updated: 2025-01-13</P> |
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| 393 | </BODY></HTML> |
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