.. index:: ! contour .. include:: module_core_purpose.rst_ ********* contour ********* |contour_purpose| Synopsis -------- .. include:: common_SYN_OPTs.rst_ **gmt contour** [ *table* ] |-J|\ *parameters* |SYN_OPT-Rz| [ |-A|\ [**n**\|\ *contours*][*labelinfo*] ] [ |SYN_OPT-B| ] [ |-C|\ *contours* ] [ |-D|\ [*template*] ] [ |-E|\ *indexfile*\ [**+b**] ] [ |-G|\ [**d**\|\ **f**\|\ **n**\|\ **l**\|\ **L**\|\ **x**\|\ **X**]\ *params* ] [ |-I| ] [ |-J|\ **z**\|\ **Z**\ *parameters* ] [ |-L|\ *pen* ] [ |-N| ] [ |-Q|\ [*n*\|\ *length*\ [*unit*]][**+z**] ] [ |-S|\ [*p*\|\ *t*] ] [ |-T|\ [**h**\|\ **l**][**+a**][**+d**\ *gap*\ [/*length*]][**+l**\ [*labels*]] ] [ |SYN_OPT-U| ] [ |SYN_OPT-V| ] [ |-W|\ [*type*]\ *pen*\ [**+c**\ [**l**\|\ **f**]] ] [ |SYN_OPT-X| ] [ |SYN_OPT-Y| ] [ |SYN_OPT-b| ] [ |SYN_OPT-d| ] [ |SYN_OPT-e| ] [ |SYN_OPT-f| ] [ |SYN_OPT-h| ] [ |SYN_OPT-i| ] [ |SYN_OPT-l| ] [ |SYN_OPT-p| ] [ |SYN_OPT-qi| ] [ |SYN_OPT-s| ] [ |SYN_OPT-t| ] [ |SYN_OPT-:| ] [ |SYN_OPT--| ] .. module_common_begins Description ----------- Reads an ASCII [or binary] *table* and produces a raw contour plot by triangulation. By default, the optimal Delaunay triangulation is performed (using either Shewchuk's [1996] or Watson's [1982] method as selected during GMT installation; run **gmt get GMT_TRIANGULATE** to see which method is selected), but the user may optionally provide a second file with network information, such as a triangular mesh used for finite element modeling. In addition to contours, the area between contours may be painted according to the CPT. Alternatively, the *x, y, z* positions of the contour lines may be saved to one or more output files (or standard output) and no plot is produced. Required Arguments ------------------ .. |Add_intables| unicode:: 0x20 .. just an invisible code .. include:: explain_intables.rst_ .. |Add_-J| replace:: |Add_-J_links| .. include:: explain_-J.rst_ :start-after: **Syntax** :end-before: **Description** .. |Add_-R| replace:: |Add_-R_auto_table| .. include:: explain_-R.rst_ :start-after: **Syntax** :end-before: **Description** .. |Add_-Rz| unicode:: 0x20 .. just an invisible code .. include:: explain_-Rz.rst_ Optional Arguments ------------------ .. _-A: **-A**\ [**n**\|\ *contours*][*labelinfo*] *contours* is annotation interval in data units; it is ignored if contour levels are given in a file via |-C|. [Default is no annotations]. Prepend **n** to disable all annotations implied by |-C|. To just select a few specific contours give them as a comma-separated string; if only a single contour please add a trailing comma so it is seen as a list and not a contour interval. The optional *labelinfo* controls the specifics of the label formatting and consists of a concatenated string made up of any of the following modifiers: .. include:: explain_clabelinfo.rst_ .. |Add_-B| replace:: |Add_-B_links| .. include:: explain_-B.rst_ :start-after: **Syntax** :end-before: **Description** .. _-C: **-C**\ *contours* The contours to be drawn may be specified in one of five possible ways: (1) If *contours* is a string with suffix ".cpt" and can be opened as a file, it is assumed to be a CPT. The color boundaries are then used as contour levels. If the CPT has annotation flags in the last column then those contours will be annotated. By default all contours are labeled; use **-An** to disable all annotations. (2) If *contours* is a file but not a CPT, it is expected to contain one record per contour, with information given in the order *contour-level* [*angle*] **C**\|\ **c**\|\ **A**\|\ **a** [*pen*], where items in brackets are optional. The levels marked **C** (or **c**) are contoured, while the levels marked **A** (or **a**) are both contoured and annotated. If the annotation *angle* is present we will plot the label at that fixed angle [aligned with the contour]. Finally, a contour- specific *pen* may be present and will override the pen set by |-W| for this contour level only. **Note**: Please specify *pen* in proper format so it can be distinguished from a plain number like *angle*. If only *cont-level* columns are present then we set type to **C**. (3) If *contours* is a string with comma-separated values it is interpreted as those specific contours only. To indicate a single specific contour you must append a trailing comma to separate it from a contour interval. The |-A| option offers the same list choice so they may be used together to plot only specific annotated and non-annotated contours. (4) If no argument is given in modern mode then we select the current CPT. (5) Otherwise, *contours* is interpreted as a constant contour interval. If a file is given and |-T| is set, then only contours marked with upper case C or A will have tick-marks. In all cases the contour values have the same units as the file. Finally, if neither |-C| nor |-A| are set then we auto-compute suitable contour and annotation intervals from the data range, yielding approximately 10-20 contours. .. _-D: **-D**\ [*template*] .. include:: explain_contdump.rst_ .. _-E: **-E**\ *indexfile*\ [**+b**] Give name of file with network information. Each record must contain triplets of node numbers for a triangle [Default computes these using Delaunay triangulation (see :doc:`triangulate`)]. If the *indexfile* is binary and can be read the same way as the binary input *table* then you can append **+b** to speed up the reading [Default reads nodes as ASCII]. .. _-G: **-G** .. include:: explain_contlabel.rst_ .. _-I: **-I** Color the triangles using the CPT. .. _-L: **-L**\ *pen* :ref:`(more ...) ` Draw the underlying triangular mesh using the specified pen attributes [Default draws no mesh]. .. _-N: **-N** Do **not** clip contours or image at the boundaries [Default will clip to fit inside region |-R|]. .. _-Q: **-Q**\ [*n*\|\ *length*\ [*unit*]][**+z**] Do not draw contours with less than *n* number of points [Draw all contours]. Alternatively, give instead a minimum contour *length* in distance units (see `Units`_ for available units and how distances are computed), including **c** (Cartesian distances using user coordinates) or **C** for plot length units in current plot units after projecting the coordinates. Optionally, append **+z** to exclude the zero contour. .. _-S: **-S**\ [**p**\|\ **t**] Skip all input *x, y, z* points that fall outside the region [Default uses all the data in the triangulation]. Alternatively, use **-St** to skip triangles whose three vertices are all outside the region. |-S| with no modifier is interpreted as **-Sp**. .. _-T: **-T**\ [**h**\|\ **l**][**+a**][**+d**\ *gap*\ [/*length*]][**+l**\ [*labels*]] .. include:: explain_contticks.rst_ .. |Add_-U| replace:: |Add_-U_links| .. include:: explain_-U.rst_ :start-after: **Syntax** :end-before: **Description** .. |Add_-V| replace:: |Add_-V_links| .. include:: explain_-V.rst_ :start-after: **Syntax** :end-before: **Description** .. _-W: **-W**\ [*type*]\ *pen*\ [**+c**\ [**l**\|\ **f**]] :ref:`(more ...) ` *type*, if present, can be **a** for annotated contours or **c** for regular contours [Default]. The *pen* sets the attributes for the particular line. Default pen for annotated contours: 0.75p,black. Regular contours use pen 0.25p,black. Normally, all contours are drawn with a fixed color determined by the pen setting. If the modifier **+cl** is appended then the colors of the contour lines are taken from the CPT (see |-C|). If instead modifier **+cf** is appended then the colors from the cpt file are applied to the contour annotations. Select **+c** for both effects. .. |Add_-XY| replace:: |Add_-XY_links| .. include:: explain_-XY.rst_ :start-after: **Syntax** :end-before: **Description** .. |Add_-bi| replace:: [Default is 3 input columns]. To use binary 4-byte integer triplets for node ids append **+b** to |-E|. .. include:: explain_-bi.rst_ .. |Add_-bo| replace:: [Default is 3 output columns]. .. include:: explain_-bo.rst_ .. |Add_-d| unicode:: 0x20 .. just an invisible code .. include:: explain_-d.rst_ .. |Add_-e| unicode:: 0x20 .. just an invisible code .. include:: explain_-e.rst_ .. |Add_-f| unicode:: 0x20 .. just an invisible code .. include:: explain_-f.rst_ .. |Add_-h| unicode:: 0x20 .. just an invisible code .. include:: explain_-h.rst_ .. include:: explain_-icols.rst_ .. |Add_-l| replace:: Normally, the annotated contour is selected for the legend. You can select the plain contour instead, or both of them, by considering the *label* to be of the format [*annotcontlabel*][/*contlabel*]. If either label contains a slash (/) character then use | instead as the separator for the two labels. .. include:: explain_-l.rst_ .. include:: explain_-qi.rst_ .. include:: explain_colon.rst_ .. |Add_perspective| unicode:: 0x20 .. just an invisible code .. include:: explain_perspective.rst_ .. include:: explain_-s.rst_ .. include:: explain_-t.rst_ .. include:: explain_help.rst_ .. include:: explain_distunits.rst_ .. module_common_ends Examples -------- .. include:: explain_example.rst_ .. include:: oneliner_info.rst_ To make a raw contour plot from the remote file Table_5.11.txt and draw the contours every 25 and annotate every 50, using the default Cartesian projection, try :: gmt contour @Table_5_11.txt -Wthin -C25 -A50 -B -pdf map To use the same data but only contour the values 750 and 800, use :: gmt contour @Table_5_11.txt -A750,800 -W0.5p -B -pdf map To create a color plot of the numerical temperature solution obtained on a triangular mesh whose node coordinates and temperatures are stored in temp.xyz and mesh arrangement is given by the file mesh.ijk, using the colors in temp.cpt, run :: gmt contour temp.xyz -R0/150/0/100 -Jx0.1i -Ctemp.cpt -G -W0.25p -pdf temp To save the triangulated 100-m contour lines in topo.txt and separate them into multisegment files (one for each contour level), try :: gmt contour topo.txt -C100 -Dcontours_%.0f.txt .. include:: contour_notes.rst_ .. include:: auto_legend_info.rst_ See Also -------- :doc:`gmt`, :doc:`gmt.conf`, :doc:`gmtcolors`, :doc:`grdcontour`, :doc:`grdimage`, :doc:`nearneighbor`, :doc:`basemap`, :doc:`colorbar`, :doc:`surface`, :doc:`triangulate`