GMS:Dataset Files

ASCII Data Set Files

Data sets can be stored to either ASCII or binary files. The default format is binary. Data sets can be saved in ASCII format by right clicking on the data set in the Project Explorer and selecting the Export command from the pop up menu. For both file formats, multiple data sets can be stored in a single file and both scalar and vector data sets can be saved to the same file. The file format is identical for 2D and 3D data sets.

For scalar data set files, one value is listed per vertex, cell, node, or scatter point. The points are listed sequentially in ascending order according to the ids of the nodes, points, vertices, or cells. For vector data set files, one set of XYZ vector components is listed per vertex, cell, node, or scatter point. If necessary, a set of status flags can be included in the file. If the status flag is false (0), the corresponding item (node, cell, etc.) is inactive. If status flags are not included in the file, it is assumed that all items are active.

The ASCII Data Set file format is as follows:

_{DATASET // File type identifier}

OBJTYPE type // Type of object data set is associated with

REFTIME reftime // A value corresponding to beginning date/time of dataset

BEGSCL // Beginning of scalar data set

OBJID id // Object id

ND numdata // Number of data values

NC numcells // Number of cells or elements

NAME "name" // Data set name

ACTTS time // Marks the active time step

MAPTS time // Marks the time step which is mapped as elevations

TS istat time // Time step of the following data

stat1 // Status flags

stat2

.

.

statnumcells

val1 // Scalar data values

val2

.

.

valnumdata

// Repeat TS card for each time step

ENDDS // End of data set

BEGVEC // Beginning of vector dataset

VECTYPE type // Vector at node/gridnode or element/cell

OBJID id // Object id

ND numdata // Number of data values

NC numcells // Number of cells or elements

NAME "name" // Data set name

TS istat time // Time step of the following data

stat1 // Status flags

stat2

.

.

statnumcells

vx1 vy1 vz1

vx2 vy2 vz2

.

.

vnumdata vnumdata vnumdata

// Repeat TS card for each time step

ENDDS // End of data set

// Repeat BEGSCL and BEGVEC sequences for each data set

Sample ASCII Data Set File:

_DATASET

OBJTYPE grid2d

REFTIME 945.348729

BEGSCL

ACTTS 1.00000000e+00

ND 8

NC 8

NAME "trichloroethylene"

TS 1 1.00000000e+00

0

0

0

1

1

1

1

0

0.00000000e+00

0.00000000e+00

0.00000000e+00

3.24000000e+00

4.39000000e+00

2.96000000e+00

7.48000000e+00

0.00000000e+00

ENDDS

BEGVEC

VECTYPE 0

ND 8

NC 8

NAME "velocity"

TS 1 5.00000000e+00

0

0

0

1

1

1

1

0

1.60000000e+01 1.60000000e+01 3.20000000e+01

6.40000000e+01 6.40000000e+01 1.28000000e+02

1.44000000e+02 1.44000000e+02 2.88000000e+02

1.96000000e+02 1.96000000e+02 3.92000000e+02

2.25000000e+02 2.25000000e+02 4.50000000e+02

9.21600000e+03 9.21600000e+03 1.84320000e+04

9.60400000e+03 9.60400000e+03 1.92080000e+04

9.80100000e+03 9.80100000e+03 1.96020000e+04

ENDDS

If variograms have been defined for a data set or time step of a data set within GMS, the variograms are saved in the data set file. The variogram cards are not documented.

The card types used in the scalar data set file format are as follows:

Card Type	DATASET
Decription	File type identifier. Must be on first line of file. No fields.
Required	YES

Card Type	OBJTYPE
Decription	Identifies the type of objects that the data sets in the file are associated with.
Required	YES. If card does not exist, the file can only be read through the Data Browser. The data sets would then be assigned to the objects corresponding to the active module.
Format	OBJTYPE type
Sample	OBJTYPE tin

Field	Variable	Value	Description
1	type	tin	TINs
		mesh2d	2D meshes
		grid2d	2D grids
		scat2d	2D scatter points
		mesh3d	3D meshes
		grid3d	3D grids
		scat3d	3D scatter points

Card Type	REFTIME
Decription	A value corresponding to the beginning date/time of the data set.
Required	NO
Format	REFTIME reftime
Sample	REFTIME 3982.897459

Field	Variable	Value	Description
1	reftime	" +/- "	A value corresponding to the beginning date/time of the data set.

Card Type	BEGSCL
Decription	Scalar data set file identifier. Marks beginning of scalar data set. No fields.
Required	YES

Card Type	BEGVEC
Decription	Vector data set file identifier. Marks beginning of vector data set. No fields.
Required	YES

Card Type	ACTTS
Decription	Used to mark the active data set. The card should be placed after the BEGSCL or BEGVEC card of the active data set and the active time step should be listed.
Required	NO
Format	ACTTS time
Sample	ACTTS 0.00

Field	Variable	Value	Description
1	time	" +/- "	The time corresponding to the active time step. Use 0.0 for steady state data sets.

Card Type	MAPTS
Decription	Used to mark the data set which is mapped to the object elevations. The card should be placed after the BEGSCL or BEGVEC card of the mapped data set and the mapped time step should be listed.
Required	NO
Format	MAPTS time
Sample	MAPTS 0.00

Field	Variable	Value	Description
1	time	" +/- "	The time corresponding to the mapped time step. Use 0.0 for steady state data sets.

Card Type	OBJID
Decription	The unique id of the object the data set is associated with.
Required	This card is required for data sets associated with TINs and scatter point sets.
Format	OBJID id
Sample	OBJID 2383

Field	Variable	Value	Description
1	id	" + "	The unique id of the object.

Card Type	VECTYPE
Decription	Identifies the type of vector data that will be read and where to apply it.
Required	This card is only required if the vector data is associated with elements/cells. If this card is not present, it is assumed that the data are associated with nodes/gridnodes.
Format	VECTYPE tpye
Sample	VECTYPE 0

Field	Variable	Value	Description
1	type	" 0,1 "	0 = The vectors will be applied to the nodes/gridnodes. 1 = The vectors will be applied to the elements/cells

Card Type	ND
Decription	The number of data values that will be listed per time step. This number should correspond to the total number of vertices, nodes, cells centers (cell-centered grid), cell corners (mesh-centered grid), maximum node id (meshes) or scatter points.
Required	YES
Format	ND numdata
Sample	ND 10098

Field	Variable	Value	Description
1	numdata	" + "	The number of items. At each time step, numdata values are printed.

Card Type	NC
Decription	This number should correspond to the maximum element id (meshes) or the number of cells (grids).
Required	YES
Format	NC numcells
Sample	NC 3982

Field	Variable	Value	Description
1	numcells	" + "	The number of elements or cells

Card Type	NAME
Decription	The name of the data set
Required	YES
Format	NAME "name"
Sample	NAME "Total head"

Field	Variable	Value	Description
1	"name"	str	The name of the dataset in double quotes.

Card Type	TS
Decription	Marks the beginning of a new time step, indicates if stat flags are given, and defines the time step value, status flags, and scalar data values for each item.
Required	YES
Format	TS istat time stat1 stat2 . . stat numcells val1 val2 . . valnumdata
Sample	TS 1 12.5 0 1 1 1 34.5 74.3 58.4 72.9

Field	Variable	Value	Description
1	istat	0,1	-
2	time	+	The time step value. If only one time step exists, the time is not required
3 - (nd+2)	stat	0,1	The status of each item. If active, stat=1. If inactive stat=0. Omitted if i=0 on STAT card.
(nd+2) - (2nd+2)	val	" +/- "	The scalar data values of each item

Cardtype	ENDDS
Description	Marks the end of a scalar opr vector data set. No fields
Required	YES

Binary Data Set Files

Data sets saved with a GMS project are saved in the binary format. The binary format is patterned after the ASCII format in that the data are grouped into "cards". However, the cards are identified by a number rather than a card title. The card ids are four byte integers. The binary format is as follows:

Card	Item	Size	Description
	version	4 byte integer	The GMS binary data set file format version. value = 3000.
100	object type	4 byte integer	Identifies the type of objects that the data sets in the file are associated with. Options are as follows: 1 TINs 2 Boreholes 3 2D meshes 4 2D grids 5 2D scatter points 6 3D meshes 7 3D grids 8 3D scatter points
110	SFLT	4 byte integer	The number of bytes that will be used in the remainder of the file for each floating point value (4, 8, or 16).
120	SFLG	4 byte integer	The number of bytes that will be used in the remainder of the file for status flags.
130 or 140	BEGSCL or BEGVEC		Marks the beginning of a set of cards defining a scalar or vector data set.
220	ACTTS	SFLT real	Marks the active data set and time step
230	MAPTS	SFLT real	Marks the mapped data set and time step
150	VECTYPE	4 byte integer	(0 or 1) In the case of vector data set files, indicates whether the vectors will be applied at the nodes/gridnodes or the elements/cells.
160	OBJID	4 byte integer	The id of the associated object. Value is ignored for grids and meshes.
170	NUMDATA	4 byte integer	The number of data values that will be listed per time step. This number should correspond to the number of vertices, nodes, cell centers (cell-centered grid), cell corners (mesh-centered grid) or scatter points.
180	NUMCELLS	4 byte integer	This number should correspond to the number of elements (meshes) or the number of cells (mesh-centered grids). Value is ignored for other object types.
190	NAME	40 bytes	The name of the dataset. Use one character per byte. Mark the end of the string with the '\0' character.
195	REFTIME	8 bytes	A value corresponding to the beginning date/time of the data set.
200	TS		Marks the beginning of a time step.
	ISTAT	SFLG integer	(0 or 1) Indicates whether or not status flags will be included in the file.
	TIME	SFLT real	Time corresponding to the time step.
	statflag1	SFLG integer	Status flag (0 or 1) for node 1
	statflag2	SFLG integer	Status flag (0 or 1) for node 2
...
	val1	SFLT real	Scalar value for item 1
	val2	SFLT real	Scalar value for item 2
...
			Repeat card 200 for each timestep in the data set.
210	ENDDS		Signal the end of a set of cards defining a data set.

The cards in the binary data set file are as follows:

Card Type	Version
Card Id	3000
Description	File type identifier. No fields.
Required	Yes

Card Type	ObjType
Card Id	100
Description	Identifies the type of objects that the data sets in the file are associated with.
Required	YES. If card does not exist, the file can only be read through the Data Browser. The data sets would then be assigned to the objects corresponding to the active module.

Feild	Variable	Size	Value	Description
1	id	4 byte int	1,2,3,4,5,6,7,8,	TINs, Boreholes, 2D meshes, 2D grids, 2D scatter points, 3D meshes, 3D grids, 3D scatter points

Using Vector and Scalar Data with Grids

For meshes, TINs, and scatter point sets, the order that the values are listed in the file is simply the sequential order of the node, TIN, or scatter point ids. However, vector and scalar data can also be associated with the nodes or cells of a 2D or 3D grid. T For 2D grids, data values are ordered using a row-column (I-J) priority. For 3D grids, data values are ordered using a layer-row-column (K-I-J) priority.

The following C source code examples illustrate how a 2D or 3D array of scalar values corresponding to the nodes of a grid would be written to the main portion of an ASCII scalar file.

2D Grid Example:

_{for(i=0; i<nrow; i++){}

for(j=0; j<ncol; j++){

fprintf(fp, "%f\n", scalar[i][j]);

}

}

3D Grid Example:

_{for(k=0; k<nlay; k++){}

for(i=0; i<nrow; i++){

for(j=0; j<ncol; j++){

fprintf(fp, "%f\n", scalar[k][i][j]);

}

}

}