1CCT(1) PROJ CCT(1)
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6 cct - Coordinate Conversion and Transformation
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9 cct [-cIostvz [args]] +opt[=arg] ... file ...
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12 cct is a 4D equivalent to the proj projection program, performs trans‐
13 formation coordinate systems on a set of input points. The coordinate
14 system transformation can include translation between projected and ge‐
15 ographic coordinates as well as the application of datum shifts.
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17 The following control parameters can appear in any order:
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19 -c <x,y,z,t>
20 Specify input columns for (up to) 4 input parameters. Defaults
21 to 1,2,3,4.
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23 -d <n> New in version 5.2.0.
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26 Specify the number of decimals in the output.
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28 -I Do the inverse transformation.
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30 -o <output file name>, --output=<output file name>
31 Specify the name of the output file.
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33 -t <time>, --time=<time>
34 Specify a fixed observation time to be used for all input data.
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36 -z <height>, --height=<height>
37 Specify a fixed observation height to be used for all input
38 data.
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40 -s <n>, --skip-lines=<n>
41 New in version 5.1.0.
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44 Skip the first n lines of input. This applies to any kind of in‐
45 put, whether it comes from STDIN, a file or interactive user in‐
46 put.
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48 -v, --verbose
49 Write non-essential, but potentially useful, information to
50 stderr. Repeat for additional information (-vv, -vvv, etc.)
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52 --version
53 Print version number.
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55 The +opt arguments are associated with coordinate operation parameters.
56 Usage varies with operation.
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58 cct is an acronym meaning Coordinate Conversion and Transformation.
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60 The acronym refers to definitions given in the OGC 08-015r2/ISO-19111
61 standard "Geographical Information -- Spatial Referencing by Coordi‐
62 nates", which defines two different classes of coordinate operations:
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64 Coordinate Conversions, which are coordinate operations where input and
65 output datum are identical (e.g. conversion from geographical to carte‐
66 sian coordinates) and
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68 Coordinate Transformations, which are coordinate operations where input
69 and output datums differ (e.g. change of reference frame).
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72 New in version 7.0.0.
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75 If the PROJ_NETWORK environment variable is set to ON, cct will attempt
76 to use remote grids stored on CDN (Content Delivery Network) storage,
77 when they are not available locally.
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79 More details are available in the network section.
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82 1. The operator specs describe the action to be performed by cct. So
83 the following script
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85 echo 12 55 0 0 | cct +proj=utm +zone=32 +ellps=GRS80
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87 will transform the input geographic coordinates into UTM zone 32 coor‐
88 dinates. Hence, the command
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90 echo 12 55 | cct -z0 -t0 +proj=utm +zone=32 +ellps=GRS80
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92 Should give results comparable to the classic proj command
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94 echo 12 55 | proj +proj=utm +zone=32 +ellps=GRS80
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96 2. Convert geographical input to UTM zone 32 on the GRS80 ellipsoid:
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98 cct +proj=utm +ellps=GRS80 +zone=32
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100 3. Roundtrip accuracy check for the case above:
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102 cct +proj=pipeline +proj=utm +ellps=GRS80 +zone=32 +step +step +inv
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104 4. As (2) but specify input columns for longitude, latitude, height and
105 time:
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107 cct -c 5,2,1,4 +proj=utm +ellps=GRS80 +zone=32
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109 5. As (2) but specify fixed height and time, hence needing only 2 cols
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112 cct -t 0 -z 0 +proj=utm +ellps=GRS80 +zone=32
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114 6. Auxiliary data following the coordinate input is forward to the out‐
115 put stream:
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117 $ echo 12 56 100 2018.0 auxiliary data | cct +proj=merc
118 1335833.8895 7522963.2411 100.0000 2018.0000 auxiliary data
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121 cct also refers to Carl Christian Tscherning (1942--2014), professor of
122 Geodesy at the University of Copenhagen, mentor and advisor for a gen‐
123 eration of Danish geodesists, colleague and collaborator for two gener‐
124 ations of global geodesists, Secretary General for the International
125 Association of Geodesy, IAG (1995--2007), fellow of the American Geo‐
126 physical Union (1991), recipient of the IAG Levallois Medal (2007), the
127 European Geosciences Union Vening Meinesz Medal (2008), and of numerous
128 other honours.
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130 cct, or Christian, as he was known to most of us, was recognized for
131 his good mood, his sharp wit, his tireless work, and his great commit‐
132 ment to the development of geodesy -- both through his scientific con‐
133 tributions, comprising more than 250 publications, and by his mentoring
134 and teaching of the next generations of geodesists.
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136 As Christian was an avid Fortran programmer, and a keen Unix connois‐
137 seur, he would have enjoyed to know that his initials would be used to
138 name a modest Unix style transformation filter, hinting at the tireless
139 aspect of his personality, which was certainly one of the reasons he
140 accomplished so much, and meant so much to so many people.
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142 Hence, in honour of cct (the geodesist) this is cct (the program).
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145 proj(1), cs2cs(1), geod(1), gie(1), projinfo(1), projsync(1)
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148 A list of know bugs can be found at
149 https://github.com/OSGeo/PROJ/issues where new bug reports can be sub‐
150 mitted to.
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153 https://proj.org/
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156 Thomas Knudsen
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159 1983-2020
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1647.2.1 Dec 25, 2020 CCT(1)