grd2xyz(1gmt) [debian man page]
GRD2XYZ(l) GRD2XYZ(l) NAME
grd2xyz - Converting a grdfile to an ASCII or binary table SYNOPSIS
grd2xyz grdfile [ -H[nrec] ] [ -L ] [ -Rwest/east/south/north[r] [ -S[r ] [ -V ] [ -Z[flags] ] [ -bo[s][n] ] DESCRIPTION
grd2xyz reads a binary 2-D grdfile and writes out xyz-triplets in ASCII [or binary] format to standard output. Modify the precision of the ASCII output format by editing the D_FORMAT parameter in your .gmtdefaults file, or choose binary output using single or double precision storage. As an option you may output z-values without the (x,y) in a number of formats, see -Z below. grdfile The 2-D binary file to be converted. OPTIONS
-H Output 1 header record based on information in the grdfile header. Ignored if binary output is selected. [Default is no header]. -L Indicates that the x values are longitudes (necessary for -: to work). -R west, east, south, and north specify the Region of interest. To specify boundaries in degrees and minutes [and seconds], use the dd:mm[:ss] format. Append r if lower left and upper right map coordinates are given instead of wesn. -S Suppress output for nodes whose z-value equals NaN [Default outputs all nodes]. Append r to reverse the suppression, i.e., only output the nodes whose z-value equals NaN. -V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"]. -Z Write a 1-column ASCII [or binary] table. Output will be organized according to the specified ordering convention contained in flags. If data should be written by 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 should start 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. For gridline registered grids: If grid is periodic in x but the outcoming data should not contain the (redundant) column at x = xmax, append x. For grid periodic in y, skip writing the redundant row at y = ymax by appending y. If the byte-order needs to be swapped, append w. Select one of several data types (all binary except a): a ASCII representation c signed 1-byte character u unsigned 1-byte character h short 2-byte integer i 4-byte integer l long (4- or 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. Note that -Z only applies to 1-column output. -bo Selects binary output. Append s for single precision [Default is double]. This option only applies to xyz output; see -Z for z ta- ble output. EXAMPLES
To edit individual values in the 5' by 5' hawaii_grv.grd file, try grd2xyz hawaii_grv.grd > hawaii_grv.xyz To write a single precision binary file without the x,y positions from the file raw_data.grd file, using scanline orientation, try grd2xyz raw_data.grd -ZTLf > hawaii_grv.b SEE ALSO
gmtdefaults(1gmt), gmt(1gmt), grdedit(1gmt), xyz2grd(1gmt) 1 Jan 2004 GRD2XYZ(l)
Check Out this Related Man Page
XYZ2GRD(l) XYZ2GRD(l) NAME
xyz2grd - Converting an ASCII or binary table to grd file format SYNOPSIS
xyz2grd xyzfile -Ggrdfile -Ix_inc[m|c][/y_inc[m|c]] -Rwest/east/south/north[r] [ -A[n|z] ] [ -Dxunit/yunit/zunit/scale/offset/title/remark ] [ -F ] [ -H[nrec] ] [ -L ] [ -Nnodata ] [ -S[zfile] ] [ -V ] [ -Z[flags] ] [ -: ] [ -bi[s][n] ] DESCRIPTION
xyz2grd reads a z or xyz table and creates a binary grdfile. 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 average value. As an option (using -Z), a 1-column z-table may be read assuming all nodes are present (z-tables can be in organized in a number of formats, see -Z below.) [xy]zfile ASCII [or binary] file holding z or (x,y,z) values. xyz triplets do not have to be sorted (for binary triplets, see -b). 1-column z tables must be sorted and the -Z must be set). -G grdfile is the name of the binary output grdfile. -I x_inc [and optionally y_inc] is the grid spacing. Append m to indicate minutes or c to indicate seconds. -R west, east, south, and north specify the Region of interest. To specify boundaries in degrees and minutes [and seconds], use the dd:mm[:ss] format. Append r if lower left and upper right map coordinates are given instead of wesn. OPTIONS
-A Add up multiple values that belong to the same node (same as -Az). Append n to simply count the number of data points that were assigned to each node. [Default (no -A option) will calculate mean value]. Ignored if -Z is given. -D Give values for xunit, yunit, zunit, scale, offset, title, and remark. To leave some of these values untouched, specify = as the value. -F Force pixel registration [Default is grid registration]. -H Input file(s) has Header record(s). Number of header records can be changed by editing your .gmtdefaults file. If used, GMT default is 1 header record. Not used with binary data. -L Indicates that the x column contains longitudes, which may differ from the regions in -R by [multiples of] 360 degrees [Default assumes no periodicity]. -N No data. Set nodes with no input xyz triplet to this value [Default is NaN]. For z-tables, this option is used to replace z-values that equal nodata with NaN. -S Swap the byte-order of the input only. No grid file is produced. You must also supply the -Z option. The output is written to zfile (or stdout if not supplied). -V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"]. -Z Read a 1-column ASCII [or binary] table. This assumes that all the nodes are present and sorted according to specified ordering con- vention 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 for- mats: start with L or R to position first column, and then append T or B to position first element in a row. For gridline regis- tered 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 sn to skip the first n number of bytes (probably a header). If the byte-order needs to be swapped, append w. Select one of several data types (all binary except a): a ASCII representation c signed 1-byte character u unsigned 1-byte character h short 2-byte integer i 4-byte integer l long (4- or 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. Note that -Z only applies to 1-column input. -: Toggles between (longitude,latitude) and (latitude,longitude) input/output. [Default is (longitude,latitude)]. Applies to geo- graphic coordinates only. -bi Selects binary input. Append s for single precision [Default is double]. Append n for the number of columns in the binary file(s). [Default is 3 input columns]. This option only applies to xyz input files; see -Z for z tables. EXAMPLES
To create a grdfile from the ASCII data in hawaii_grv.xyz, try xyz2grd hawaii_grv.xyz -Ddegree/degree/mGal/1/0/"Hawaiian Gravity"/"GRS-80 Ellipsoid used" -Ghawaii_grv_new.grd -R198/208/18/25 -I5m -V To create a grdfile from the raw binary (3-column, single-precision) scanline-oriented data raw.b, try xyz2grd raw.b -Dm/m/m/1/0/=/= -Graw.grd -R0/100/0/100 -I1 -V -Z -b3 To make a grdfile from the raw binary USGS DEM (short integer) scanline-oriented data topo30. on the NGDC 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), try xyz2grd topo30. -Dm/m/m/1/0/=/= -Gustopo.grd -R234/294/24/50 -I30c -N-9999 -V -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 xyz2grd floats.bin -Snew_floats.bin -V -Zf SEE ALSO
gmt(1gmt), grd2xyz(1gmt), grdedit(1gmt) 1 Jan 2004 XYZ2GRD(l)