.. index:: ! xyz2grd .. include:: module_core_purpose.rst_ ******* xyz2grd ******* |xyz2grd_purpose| Synopsis -------- .. include:: common_SYN_OPTs.rst_ **gmt xyz2grd** [ *table* ] |-G|\ *outgrid* |SYN_OPT-I| |SYN_OPT-R| [ |-A|\ [**d**\|\ **f**\|\ **l**\|\ **m**\|\ **n**\|\ **r**\|\ **S**\|\ **s**\|\ **u**\|\ **z**] ] [ |SYN_OPT-D2| ] [ |-J|\ *parameters* ] [ |-S|\ [*zfile*] ] [ |SYN_OPT-V| ] [ |-Z|\ [*flags*] ] [ |SYN_OPT-bi| ] [ |SYN_OPT-di| ] [ |SYN_OPT-e| ] [ |SYN_OPT-f| ] [ |SYN_OPT-h| ] [ |SYN_OPT-i| ] [ |SYN_OPT-qi| ] [ |SYN_OPT-r| ] [ |SYN_OPT-w| ] [ |SYN_OPT-:| ] [ |SYN_OPT--| ] |No-spaces| Description ----------- **xyz2grd** reads one or more *x, y, z* or *z* tables and creates a binary grid file. **xyz2grd** will report if some of the nodes are not filled in with data. Such unconstrained nodes are set to a value specified by the user [Default is NaN]. Nodes with more than one value will be set to the mean value. As an option (using |-Z|), a 1-column *z* table may be read assuming all nodes are present (*z* tables can be organized in a number of formats, see |-Z| below.) **Note**: **xyz2grd** does not grid the data, it simply reformats existing data to a grid structure. For gridding, see :doc:`surface`, :doc:`greenspline`, :doc:`nearneighbor`, or :doc:`triangulate`. Required Arguments ------------------ *table* One or more ASCII [or binary, see **-bi**] files holding *z* or *x, y, z* values. The *x, y, z* triplets do not have to be sorted. One-column *z* tables must be sorted and the |-Z| option must be set. .. _-G: .. |Add_outgrid| replace:: Give the name of the output grid file. .. include:: /explain_grd_inout.rst_ :start-after: outgrid-syntax-begins :end-before: outgrid-syntax-ends .. _-I: .. include:: explain_-I.rst_ .. |Add_-R| replace:: |Add_-R_links| .. include:: explain_-R.rst_ :start-after: **Syntax** :end-before: **Description** Optional Arguments ------------------ .. _-A: **-A**\ [**d**\|\ **f**\|\ **l**\|\ **m**\|\ **n**\|\ **r**\|\ **S**\|\ **s**\|\ **u**\|\ **z**] By default we will calculate mean values if multiple entries fall on the same node. Use |-A| to change this behavior, except it is ignored if |-Z| is given. Append a desired directive: - **d**: Find the difference between the maximum and minimum values at each node. - **f**: Simply keep the first data point that was assigned to each node. - **l**: Find the lowest (minimum) value at each node. - **m**: Compute the mean of all values falling to each node [Default]. - **n**: Report the number of data points that were assigned to each node (this only requires two input columns *x* and *y* as *z* is not consulted). - **r**: Compute the rms of all values falling to each node. - **S**: Compute the standard deviation of all values falling to each node. - **s**: Simply keep the last data point that was assigned to each node. - **u**: Find the upper (maximum) value at each node. - **z**: Report sum of multiple values that belong to the same node. .. _-D: .. include:: explain_-D_cap.rst_ .. |Add_-J| replace:: Use the |-J| syntax to save the georeferencing info as CF-1 compliant metadata in netCDF grids. Remember also that PROJ syntax can be used directly in |-J|. This referencing will be recognized by GDAL and increasingly also by GMT. .. include:: explain_-J.rst_ :start-after: **Syntax** :end-before: **Description** .. _-S: **-S**\ [*zfile*] Swap the byte-order of the *z* table input only. No grid file is produced. You must also supply the |-Z| option. The output is written to *zfile* (or standard output if not supplied). .. |Add_-V| replace:: |Add_-V_links| .. include:: explain_-V.rst_ :start-after: **Syntax** :end-before: **Description** .. _-Z: **-Z**\ [*flags*] Read a 1-column ASCII [or binary] table. This assumes that all the nodes are present and sorted according to specified ordering convention contained in *flags*. If incoming data represents rows, make *flags* start with **T**\ (op) if first row is *y = ymax* or **B**\ (ottom) if first row is *y = ymin*. Then, append **L** or **R** to indicate that first element is at left or right end of row. Likewise for column formats: start with **L** or **R** to position first column, and then append **T** or **B** to position first element in a row. **Note**: These two row/column indicators are only required for grids; for other tables they do not apply. For gridline registered grids: If data are periodic in *x* but the incoming data do not contain the (redundant) column at *x = xmax*, append **x**. For data periodic in *y* without redundant row at *y = ymax*, append **y**. Append **s**\ *n* to skip the first *n* number of bytes (probably a header). If the byte-order or the words needs to be swapped, append **w**. Select one of several data types (all binary except **a**): - **A** ASCII representation of one or more floating point values per record - **a** ASCII representation of a single item per record - **c** int8_t, signed 1-byte character - **u** uint8_t, unsigned 1-byte character - **h** int16_t, signed 2-byte integer - **H** uint16_t, unsigned 2-byte integer - **i** int32_t, signed 4-byte integer - **I** uint32_t, unsigned 4-byte integer - **l** int64_t, long (8-byte) integer - **L** uint64_t, unsigned long (8-byte) integer - **f** 4-byte floating point single precision - **d** 8-byte floating point double precision Default format is scanline orientation of ASCII numbers: **-ZTLa**. The difference between **A** and **a** is that the latter can decode both *date*\ **T**\ *clock* and *ddd:mm:ss[.xx]* formats but expects each input record to have a single value, while the former can handle multiple values per record but can only parse regular floating point values. Translate incoming *z*-values via the **-i**\ 0 option and needed modifiers. .. |Add_-bi| replace:: [Default is 3 input columns]. This option only applies to *x, y, z* input files; see |-Z| for *z* tables. .. include:: explain_-bi.rst_ .. |Add_-di| replace:: Also sets nodes with no input *x, y, z* triplet to this value [Default is NaN]. .. include:: explain_-di.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| replace:: Not used with binary data. .. include:: explain_-h.rst_ .. include:: explain_-icols.rst_ .. include:: explain_-qi.rst_ .. |Add_nodereg| unicode:: 0x20 .. just an invisible code .. include:: explain_nodereg.rst_ .. include:: explain_-w.rst_ .. include:: explain_colon.rst_ .. include:: explain_help.rst_ .. include:: explain_float.rst_ .. include:: explain_grd_coord.rst_ Swapping Limitations -------------------- All data types can be read, even 64-bit integers, but internally grids are stored using floats. Hence, integer values exceeding the float type's 23-bit mantissa may not be represented exactly. When |-S| is used no grids are implied and we read data into an intermediate double container. This means all but 64-bit integers can be represented using the double type's 53-bit mantissa. Examples -------- .. include:: explain_example.rst_ To create a grid file from the ASCII data in hawaii\_grv.xyz, use :: gmt xyz2grd hawaii_grv.xyz -D+xdegree+ydegree+zGal+t"Hawaiian Gravity"+r"GRS-80 Ellipsoid used" \ -Ghawaii_grv_new.nc -R198/208/18/25 -I5m -V To create a grid file from the raw binary (3-column, single-precision scanline-oriented data raw.b, use :: gmt xyz2grd raw.b -D+xm+ym+zm -Graw.nc -R0/100/0/100 -I1 -V -Z -bi3f To make a grid file from the raw binary USGS DEM (short integer scanline-oriented data topo30.b on the NCEI global relief Data CD-ROM, with values of -9999 indicate missing data, one must on some machine reverse the byte-order. On such machines (like Sun), use :: gmt xyz2grd topo30.b -D+xm+ym+zm -Gustopo.nc -R234/294/24/50 -I30s -di-9999 -ZTLhw Say you have received a binary file with 4-byte floating points that were written on a machine of different byte-order than yours. You can swap the byte-order with :: gmt xyz2grd floats.bin -Snew_floats.bin -V -Zf To make a pixel node registrated tiff of the number of data points that is assigned to each node in a cartesian data set, use :: gmt xyz2grd data.txt -R0/100/0/100 -r -I10 -An -Gnumber_of_points.tif=gd:GTiff See Also -------- :doc:`gmt`, :doc:`grd2xyz`, :doc:`grdedit`, :doc:`grdconvert`, :doc:`greenspline`, :doc:`nearneighbor`, :doc:`surface`, :doc:`triangulate`