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5.7 Raster Modules

The raster modules can accommodate image data, digital terrain models, gridded GIS layers, other gridded data, and a voxel space. For the purposes of this specification, raster, grid, voxel space, or image data will all be referred to as raster data. A raster object may consist of different layers, each layer being composed of a number of grid cells, pixels, voxels, or n-dimensional cells (See 2.3.4.3), henceforth to be referred to as cells, arranged in an array.

Many different types of organizational schemes exist for raster data. To distinguish between the main aspects of these schemes, the concept of an object representation code has been carried through to this transfer form. A two-dimensional grid or digital image is object code G2. A three-dimensional voxel space is a G3. A two or three dimensional grid that varies (has discrete labeled axes) is a GV.

A raster object consists of one or more related layers of cells arranged in such a way that corresponding cells between layers are registered to a common scan reference system (to be defined) and overlap, but need not be of the same spatial extent.

There are three different types of raster modules: the Raster Definition module, the Layer Definition module, and the Cell module. A typical transfer of a raster object can require one Raster Definition module, one Layer Definition module, several Cell modules, one Internal Spatial Reference module, one External Spatial Reference module, the Data Dictionary modules, as well as other miscellaneous modules. A Raster Definition module record must reference one or more layers. Each Layer Definition record must reference one Cell Module or equivalent. One Cell Module must only contain cells from one layer, unless the layers are interleaved, in which case it must contain cells from all.

5.7.1 Raster Definition Module

The Raster Definition module (see Table 42) is used to define each raster object in the system. One Raster Definition module record corresponds to one raster object. A raster object is defined by one or more layers, as defined in the Layer Definition module. The raster object internal reference system is defined by the Internal Spatial Reference record pointed to by the Raster Definition records Internal Spatial ID field.

Raster objects are usually two dimensional, but this standard also supports additional dimensions as needed. The additional dimensions for a raster object are defined by having the coresponding Internal Spatial Reference record point to each additional dimension through the Dimension ID field. All dimensions, geospatial and nongeospatial, are defined through the Internal Reference module and the Dimension Definition module, respectively.

The registration of a raster object is defined by two categories of information; the location, Spatial Address (SADR), of the origin of the scan reference system, and the size of the raster objects cells. The cell size is derived from the Internal Spatial Reference record and/or Dimension Definitions record(s) pointed to by a raster object. If any of the dimension's cell sizes are zero, that dimension, geospatial or nongeospatial, will be explicitly labeled using the corresponding repeating Label field. The number of repetitions of the Label fields is determined by the value found in the Corresponding Extent subfield, i.e. for each position a cell might reside along the axis an associated registration value will be defined. Labeling is only permitted for the following Object Representation Codes: GV.

The main components of the Raster Definition module are:

a) a primary field consisting of subfields defining the geospatial dimensions of the raster object scan reference system as well as global cell sequencing parameters,

b) an Internal Spatial Id field pointing to the Internal Spatial Reference record defining all dimensions of the raster object,

c) a repeating nongeospatial raster extent field, used to describe the nongeospatial dimensions of the raster object scan reference system,

d) a Spatial Address field used to locate the origin of the raster object scan reference system,

e) a repeating X-Axis label field used when the resolution along the X-Axis is not fixed, each position along the grid will be explicitly labeled here. Similarly for all dimensions.

f) a repeatable Layer ID field; each field points to the Layer Definition module record which define the layers of this raster object.

5.7.2 Layer Definition Module

Each Layer Definition module record (see Table 43) describes one layer of a raster. The format, definition and domain of the layer are stored in the respective Data Dictionary modules. The Attribute Label subfield found in the Data Dictionary modules will contain the name of the layer as it appears in the Layer Label subfield of the Layer Definition record, thereby making it possible to relate the Data Dictionary records to the Layer Definition records. Each record in this module will be referenced by only one Layer ID field from the Raster Definition module, thereby making it impossible to reuse the Layer Definition records for multiple raster objects. Each record of the Layer Definition module will be uniquely identified by the name of the layer in conjunction with the name of the cell module into which the cell values for the layer will reside. The information found in this module will define the layer scan reference system.

The main components of the Layer Definition module are:

a) primary field consisting of subfields pertaining to the entire layer,

b) an optionally repeating Layer Extent field used to describe the extents of the layer for nongeospatial dimensions, as described in the corresponding Dimension Definition module. The extents for geospatial dimensions are described in the primary field, separate from the nongeospatial dimensions, and

c) a repeating Layer Attribute ID for attributes of the layer.

5.7.3 Cell Module

The Cell module contains the actual data values for the raster (see Table 44).

The module record of the Cell module has been designed so that each module record can hold information on a number of related cells. Designating these related cells as a "stream" to facilitate the following explanation, examples of a stream are a single scan line of an image, a number of layer-interleaved scan lines as a part of an image, a single cell, a block of a quad tree, or even an entire layer of a raster. A stream does not necessarily start at the beginning of a line or row, but can start in the middle of row i, proceed through rows i through n - 1, and terminate somewhere in row n. If the raster object is of three or greater dimensions then the order of cells in the module may be affected by the order Dimension ID fields are found in the corresponding Internal Spatial Reference record for the raster object (see Annex F).

The main components of the Cell module are:

a) a primary field with the number of cells per record and a row, a column and a plane index; the index is used to locate the first cell in the record inside of the layer scan reference system,

b) a repeating Dimension Index field used to locate the first cell in the record inside the layer scan reference system for the dimension,

c) an attribute foreign identifier for the stream, and

d) a Cell Values field with a number of layer subfields, each to be repeated for each cell value. The attribute link can be used, for instance, to store ancillary data with a layer interleaved scan line, or it can be used to associate a full set of attributes with each run encoded cell.

5.7.4 Object Representation Codes

Any of the object representation codes may be used, but their use is dependent on the configuration of the Internal Spatial Reference record pointed to by the RSDF/ISID. Table 40 summarizes the rules for each object representation code:

The Internal Spatial Reference module must be consistent with the Object Representation Code selected. The Object Representation Code will be used to configure the Raster modules for encoding the raster data.

5.7.5 Default Implementation

The Raster Definition and Layer Definition modules have a strongly recommended default implementation in which a number of subfields have default values. Subfields with a default value are indicated by the symbol "(d)" preceding the field name in the module specification table, as defined in 4.2.3.7. Table 41 - lists the subfields values that must be present when the default implementation is used

5.7.6 Tesseral Indexing.

The use of the raster portion of the standard is not restricted to raster transfer using a row-column layout. Rasters can be divided into tiles of regular or irregular size and can be transferred on a tile basis. To fit this type of organization into the SDTS model, each tile is equated with a stream. Each stream (tile) can be preceded by a row-column address, or alternately, a tesseral index can be used. A tesseral index is not the equivalent of a row and column address, because the index can contain the extent of the tile as well through the use of wildcard components. The type of tesseral index must conform to the contents of the Scan Pattern subfield of the Raster Definition module and can, therefore, only be a Linear, Boustro, Morton, or Peano key.

Use of tesseral indexing must be indicated through the Tesseral Indexing Description subfield, and the type of data structure, particular method, and meaning of the index digits must be specified in the Tesseral Index Format subfield.

5.7.7 Cell Encoding.

Various methods are possible for assigning a unique attribute value to each cell in a raster. The Cell Encoding Type subfield of the Raster Definition module specifies the method used. The possible values are: "L", indicating that the presence or absence of the attribute is coded for each cell; "D", indicating that the value assigned occupies the greatest area of the cell; "F", indicating that the value assigned is the one that occurs most frequently within the cell; "V", indicating that the value is a continuous numeric variable measured at the center of the cell; or "X", indicating that the value is a code representing a value defined in a corresponding Data Dictionary/Domain module.

5.7.8 Registration of Cell Values to the External Reference system.

Spatial referencing for raster data must be governed by parameters transferred in the Spatial Reference modules. For raster data with a known and expressed relationship to latitude and longitude, spatial registration conformance level 2 (See 5.2.4.2) might be the best registration level, allowing the raster data to remain untransformed in a specified projection that is not one of the three preferred systems (GEO, UTM/UPS, or SPCS). Use of one of these three preferred systems might result in a loss of information because of transformation.

For complete details on converting from raster coordinate systems to internal coordinates see Annex F.

5.7.9 Radiometric Information.

For remotely sensed images, radiometric infoirmation is of utmost importance for the correct utilization of the imagery. There is no standardized set of radiometric parameters. Therefore producer defined attributes can be used to encode radiometry.

5.7.10 Alternate Formats: Compression and Adjunct Files.

This standard permits raster data to be compressed. It also permits file encodings for raster data other than prescribed in Part 3. Compression methods and alternate file formats can be used independently. The method and details for decompressing or reading the alternate format must be specified by a profile document. The use of compression and (or) use of adjunct files is indicated in the Raster Definition module and thus applies to the entire raster. The Layer Definition module references the specific Cell module for part 3 encodings or a file id for adjunct file. The logical id can then be used to look up the physical file name in the Catalog/Directory module.

5.7.10.1 Run Length Encoding

The Run Length Encoding method of compressing cell values is specified in this standard as a permitted (optional) method of compression. The use of Run Length Encoding is indicated by placing the value "RLE" in the Data Compression Method subfield of the Raster Definition Module. Run length encoding is a method where a cell value and a run count is given that indicates the number of consecutive cells with the same value. This method is most applicable to gridded raster data which is not interleaved with other raster layers. The meaning of "consecutive cells" is dependent on the overall cell ordering as described by the subfields of the applicable Raster Definition and Layer Definition module records.

For RLE, the two subfields of the Cell Values field of the Cell Module must be (1) a user-defined cell value subfield (for example, LANDUSE, SOILTYPE, or WETLANDTYPE) and (2) a subfield named RLECOUNT.

Table 40 - Rules to configure the internal spatial reference record for the various types of raster object representation codes

	The internal spatial reference record will be configured as:
Object rep. code	X	Y	Z	Dimension ID1	Resolution2
G2	Yes	Yes	No	Optional	Nonzero
G3	Yes	Yes	Yes	Optional	Nonzero
GV	Yes	Yes	No	Optional	Some Zero
GV	Yes	Yes	Yes	Optional	Some Zero

1 This use of the Dimension ID field is optional but, if it is used, it will apply to all layers of the raster. 2 Nonzero - All dimensions will have nonzero resolutions. Some Zero - At least one dimensions resolution will be zero

Table 41 - Mandatory values for default raster implementation

Module	Subfield name	Default1
Raster	Scan Origin	TLor TLZN2
	Scan Pattern	LINEAR
	Tesseral Indexing	NOTESS
	Number of Lines per	1
	First Scan Direction	R or RC2
	Aspect Ratio	1
	Dimension Scan Origin	NP
	Data Compression	NON
Layer	Scan Origin Row	1
	Scan Origin Column	1
	Scan Origin Plane	1
	Scan Origin Dimension	1
	Row Offset Origin	0
	Column Offset Origin	0
	Plane Offset Origin	0
	Dimension Offset Origin	0
	Intracell Reference	TL or TLF2
	Dimension Intracell Reference	F

1 Not all default implementation values are relevant for all Object Representation codes, because not all subfields will not be present for all Object Representation codes. 2 The first value is used when the raster uses the two geospatial dimensions, X and Y. The second value is used when all three geospatial dimensions are used, X, Y, and Z.

Table 42 - Raster definition module specification

FIELD NAME	SUBFIELD NAME	FIELD/SUBFIELD DESCRIPTION	TYPE	DOMAIN	DOMAIN DESCRIPTION	MNEMONIC
Raster Definition (P) [M]						RSDF
	Module Name [M]	A unique identifier for the module.	A	Alphanum	Name must begin with alphabetic character other than SPACE	MODN
	Record ID [M]	Raster object record identifier.	I	Integer	Unsigned integer; with Module Name must form a unique ID within the file set.	RCID
	Object Representation [M]	Representation code for the raster object. (must be the same for all layers referenced)	A	G2 G3 GV	2-D geospatial grid or image. 3-D voxel space. Rectangle variant grid.	OBRP
	Cell Sequencing Code [M]	A code which indicates how cells will be sequenced in the Layers (i.e. between their Cell modules.)	A	GI GJ GL	Layer sequential. Layer interleaved by line. Layer Interleaved by pixel.	CSCD
	Acquisition Device/Method	Sensor or acquisition device from which the data originated and method by which the data were acquired/processed.	A	Gr-chars	Any combination of graphics characters.	AQMD
	Acquisition Date	Acquisition date for the data.	A	cs:FIPSPUB4	FIPSPUB 4 specified date.	AQDT
	Comments	Any desired comments pertaining to the entire raster.	A	Gr-chars	Any combination of graphics characters.	COMT
	Default Implementation [M]	Signifies whether the module version is a default implementation or not. (See 5.7.5)	A	DEF NON	Default Implementation Nondefault Implementation	DEFI
Note: The next four subfields describe the data encoding; must be the same for all layers referenced.
	(d)Data Compression [M/DEFI=NON]	Signifies whether data compression is in effect or not.	A	COM NON	Compressed raster data. Raster data not compressed.	CMPR
	Data Compression Method [A/CMPR=NON]	Description of the compression method used; applies to the entire raster being described.	A	RLE	Run length encoding as described in 5.7.10.1.	CMMD
				Gr-chars	Compression method as identified by a profile.
	(^)Decompression Parameters	Foreign id to Attribute record containing parameters needed to decompress raster data. (As required by a profile.)				DCOM
	(d)Coding Method	Indicates whether raster data is encoded in files according to SDTS Part3 (ISO 8211)--the default, or whether another file format is in use (adjunct file).	A	ISO8211	Raster data in Part3/ISO8211.	METH
				Gr-chars	Raster data in another format as specified by a profile.
Note: The following three subfields describe the size of the raster object, within which all raster layers belonging to the raster object reside.
	Row Extent [M]	Number of rows in the union of the geospatial extent of all layers, including the origin of the scan reference system.	I	Integer	Unsigned integer >= 1.	RWXT
	Column Extent [M]	Number of columns in the union of the geospatial extent of all layers, including the origin of the scan reference system.	I	Integer	Unsigned integer >=1.	CLXT
	Plane Extent [A/G2]	Number of planes in the union of the geospatial extent of all layers, including the origin of the scan reference system.	I	Integer	Unsigned integer >= 1.	PLXT
	(d)Scan Origin [M]	Location of the first cell with respect to the image viewed as a rectangle. Orientation of the raster object scan reference system with respect to the internal reference system.	A	TL	[2-d] Origin top left.	SCOR
				TR	[2-d] Origin top right
				BL	[2-d] Origin bottom left
				BR	[2-d] Origin bottom right
				TLZN	[3-d] Top left Z-neg to pos
				TLZP	[3-d] Top left Z-pos to neg
				TRZN	[3-d] Top right Z-neg to pos
				TRZP	[3-d] Top right Z-pos to neg
				BLZN	[3-d] Bottom left Z-neg to pos
				BLZP	[3-d] Bottom left Z-pos to neg
				BRZN	[3-d] Bottom right Z-neg to pos
				BRZP	[3-d] Bottom right Z-pos to neg
	(d)Scan Pattern	Scan pattern for the raster.	A	LINEAR	Scan by row or by column (begin-end-begin-end..).	SCPT
				BOUSTRO	Boustrophedonic scan order (begin-end-end-begin..).
				MORTON	Morton or Z order.
				PEANO	Hilbert-Peano order.
	(d)Tesseral Indexing [M]	Signifies whether tesseral indexing is used or not.	A	TESS NOTESS	Tesseral indexing used. No tesseral indexing used.	TIDX
	Tesseral Index Format [A/Tesseral Indexing = NOTESS]	Format for the tesseral index.	A	I B BI8 BI16 BI24 BI32 BUI BUI8 BUI16 BUI24 BUI32 C	Implicit-point (integer) Binary 8-bit signed integer 16-bit signed integer 24-bit signed integer 32-bit signed integer Unsigned integer 8-bit unsigned integer 16-bit unsigned integer 24-bit unsigned integer 32-bit unsigned integer Character mode bitfield	TIFT
	Tesseral Indexing Description [A/Tesseral Indexing = NOTESS]	Gives further information on data structure, indexing method, and meaning of index components.	A	Gr-chars	Any combination of graphics characters.	TIDS
	(d)Number of Lines per Alternation	Number of line per alternation in the scan pattern.	I	Integer	Unsigned integer >= 1	ALTN
	(d)First Scan Direction [M]	Direction (row or column) of the first scan.	A	2-d geospatial choices:		FSCN
				R	First scan proceeds by row.
				C	First scan proceeds by column.
				3-d geospatial choices:
				RC	Expand by Row, Column Plane
				CR	Expand by Column, Row, Plane
				RP	Expand by Row, Plane, Column
				PR	Expand by Plane, Row, Column
				CP	Expand by Column, Plane, Row
				PC	Expand by Plane, Column, Row
	(d)Aspect Ratio [A/G3]	Aspect ratio of cells: cell row spacing divided by cell line spacing. Only meaningful for two dimensional rasters.	R	Real	Aspect ratio of cells: cell row spacing divided by cell column spacing.	ASPR
	Number of Layers [M]	Number of cell layers (e.g., spectral bands).	I	Integer	Unsigned integer >= 1	NLAY
(^) Internal Spatial ID [M](N)		A pointer to the Internal Spatial Reference record which defines all dimensions of this raster object.				ISID
Raster Dimension Extent (O) [M/Dimension ID][A]		This field will describe this raster object's extent along the dimension. There should be one field for each Dimension ID Field in the IREF module record referenced above. The order of the fields here must correspond with the order of the DMID field repetition in the IREF module record.				RDXT
	Dimension Extent [M]	The Extent for a dimension of this raster.	I	Integer	Unsigned Integer > 0	DEXT
	Dimension Scan Origin [M]	The orientation of the raster object scan reference system with respect to the internal reference system for the dimension.	A	PN NP	Positive to Negative Negative to Positive	DSCO
(-) Spatial Address[M] (N)		The Spatial Address of the origin of the raster object scan reference system.				SADR
X-Axis Label(O) [A/G2|G3| X Component of Horizontal Resolution != 0]		The number of repetitions is defined by the Column Extent subfield. The order of repetition must be in ascending order along the axis.				XXLB
	Column Axis Value [M]	Value for a position along the X axis.	I|R|S|B	Integer Real Binary	As defined by the Horizontal Component Format for the corresponding Internal Reference module.	CAVL
Y-Axis Label(O) [A/G2|G3| Y Component of Horizontal Resolution != 0]		The number of repetitions is defined by the Row Extent subfield. The order of repetition must be in ascending order along the axis.				YXLB
	Row Axis Value [M]	A value for a position along the Y axis.	I|R|S|B	Integer Real Binary	As defined by the Horizontal Component Format for the corresponding Internal Reference module.	RAVL
Z-Axis Label(O) [A/G2|G3|G2L | Vertical Resolution Component != 0]		The number of repetitions is defined by the Plane Extent subfield. The order of repetition must be in ascending order along the axis.				ZXLB
	Plane Axis Value [M]	A value for a position along the Z axis.	I|R|S|B	Integer Real Binary	As defined by the Vertical Component Format for the corresponding Internal Reference module.	ZAVL
Dimension Axis Label [O/Dimension ID] [A/G2|G3|Dimension Component of Resolution != 0 | Dimension Component Format != A]		The number of repetitions defines the extent for this axis. The order of repetition must be in ascending order along the axis. If more than one nongeospatial dimension has a need to explicitly label the axis, multiple permutations of this field will be necessary, i.e. one permutation per dimension which needs it. The field mnemonic will be altered for each permutation.				DAL1 DAL2 . . DALn
	Dimension Axis Value [M]	A value for a position along this axis	A|I|R|S|C|B	Integer Real Alpha Binary	As defined by the Dimension Component Format in the corresponding Dimension Definition Module.	DXVL
(^) Layer ID (O) [M]		Foreign identifier pointing to the layer definition records which constitute this raster. The ordering for the instances of this field is with respect to the layers of the raster data as they occur in the Cell module.				LYID
(^)Raster Attribute ID (R)		Foreign identifier for Attribute Primary module record. Attributes pertain to entire raster object.				RATP
(^)Composite ID (R)		Contains foreign identifier of Composite module record that includes this raster object.				CPID
(continued)

Table 43 - Layer definition module specification

FIELD NAME	SUBFIELD NAME	FIELD/SUBFIELD DESCRIPTION	TYPE	DOMAIN	DOMAIN DESCRIPTION	MNEMONIC
Layer Definition (P) [M]		One Layer Definition record for each data layer.				LDEF
	Module Name [M]	A unique identifier for the module.	A	Alphanum	Name must begin with alphabetic character other than SPACE	MODN
	Record ID [M]	A number for the module record, unique within the module.	I	Integer	Unsigned integer; with Module Name must form unique ID within the file set.	RCID
	Cell Module Name or Adjunct File Id [M] (N)	Name of the Cell module to which this Layer Definition record applies; or an identifier for an adjunct file which contains the raster data for this layer. [The filename can be found in the Catalog/directory module.]	A	Alphanum	Logical name of where to find the data for this layer. Name of Cell module to which this Layer Definition record applies; or an identifier for an adjunct file which contains the raster data for this layer.	CMNM
	Layer Label [M]	Short name/mnemonic for the layer as defined in the Data Dictionary modules. This value will be unique to all other layer labels in the same logical raster.	A	Gr-chars	Cell value name, used to indicate the type of value stored here. These layers will be described by the Data Dictionary.	LLBL
	Cell Code[M]	Cell value encoding method; how to interpret the cell value.	A	L	Presence/absence of theme in cell.	CODE
				D	Dominate type of area.
				F	Dominant type by frequency.
				V	Value of a continuum attribute variable.
				X	Assign code, must be defined in Data Dictionary/Domain module.
	Bitmask	Defines bitfield length and active bits of an individual cell value as a binary string. (Used for example to transfer 3-bit data using 8-bits with a mask of say 00000111.)	C	C	An ordered list corresponding to unused (zero) and active (one) positions of bitfield bits.	BMSK
	Number of Rows [M]	Number of rows in the layer	I	Integer	Cannot exceed Row Extent.	NROW
	Number of Columns [M]	Number of columns in the layer.	I	Integer	Cannot exceed Column Extent	NCOL
	Number of Planes [A/G2]	Number of planes in the layer.	I	Integer	Cannot exceed Plane Extent	NPLA
Note: The next group of subfields has information about the scan reference system origin for the layer
	(d)Scan Origin Row [M]	Designates whether row index starts at 0 or 1.	I	0 1	First cell occurs at row 0. First cell occurs at row 1.	SORI
	(d)Scan Origin Column [M]	Designates whether column index starts at 0 or 1.	I	0 1	First cell occurs at column 0. First cell occurs at column 1.	SOCI
	(d)Scan Origin Plane[A/G2]	Designates whether plane index starts at 0 or 1.	I	0 1	First cell occurs at plane 0. First cell occurs at plane 1.	SOPI
	(d)Row Offset Origin [M]	Number of Rows to offset the layer scan reference system to place the layer into the raster object scan reference system.	I	Integer	Unsigned integer >= 0.	RWOO
	(d)Column Offset Origin [M]	Number of columns to offset the layer scan reference system to place the layer into the raster object scan reference system.	I	Integer	Unsigned integer >= 0.	CLOO
	(d)Plane Offset Origin [A/G2]	Number of planes to offset the layer scan reference system to place the layer into the raster object scan reference system.	I	Integer	Unsigned integer >= 0.	PLOO
	(d)Intracell Reference Location [M]	Relative location of the internal reference system origin within the cell.	A	2d geospatial choices:		INTR
				TL	Top left of cell
				TR	Top right of cell
				BL	Bottom left of cell
				BR	Bottom right of cell
				CE	Center of cell
				3d geospatial choices:
				TLF	Top left front of cell
				TLB	Top left back of cell
				TRF	Top right front of cell
				TRB	Top right back of cell
				BLF	Bottom left front of cell
				BLB	Bottom left back of cell
				BRF	Bottom right front of cell
				BRB	Bottom right back of cell
				CEN	Center of the voxel or cube
	Comment	Comments pertaining to the specific layer.	A	Gr-chars		COMT
Layer Dimension Extent (O) [M/Dimension ID][A]		This field will describe this layer's extent along this dimension. The order this field repeats and the number of repetitions must be correlated with the Dimension ID fields of the IREF record referenced by the RDEF record that includes this LDEF record.				LDXT
	Dimension Extent [M]	The Extent for a dimension of this layer	I	Integer	Unsigned Integer > 0	DEXT
	Scan Origin Dimension [M]	Designates whether dimension index starts at 0 or 1.	I	0 1	First cell occurs at position 0. First cell occurs at position 1.	SODM
	Dimension Offset Origin [M]	Number of positions along the dimension to offset the layer scan reference system to place the layer into the raster object scan reference system.	I	Integer	Unsigned Integer >=0.	DTOO
	Dimension Intracell Reference Location [M]	Relative location of the internal reference system origin within the cell along this dimension.	A	F C B	Front of cell - toward origin. Center of cell. Back of cell - away from origin.	DINR
(^)Layer Attribute ID (O)		Foreign identifier for Attribute Primary module record. Attribute pertain to a specific layer.				LATP
(continued)

Table 44 - Cell module specification

FIELD NAME	SUBFIELD NAME	FIELD/SUBFIELD DESCRIPTION	TYPE	DOMAIN	DOMAIN DESCRIPTION	MNEMONIC
Cell (P) [M]						CELL
	Module Name [M]	A unique identifier for the module.	A	Alphanum	Name must begin with alphabetic character other than SPACE.	MODN
	Record ID [M]	A number for the module record, unique within the module.	I	Integer	Unsigned integer; with Module Name must form unique ID within the file set.	RCID
	Number of Cells	Number of cell fields in this module record	I	Integer	Unsigned Integer >= 1.	NCEL
	Row Index [O/Tesseral Index = TESS]	Row index of first cell in module record. (layer scan reference system)	I	Integer	Unsigned Integer >= 1.	ROWI
	Column Index [O/Tesseral Index = TESS]	Column index of first cell in module record. (layer scan reference system)	I	Integer	Unsigned Integer >= 1.	COLI
	Plane Index [O/Tesseral Index = TESS] [A/G2]	Plane index of first cell in module record. (layer scan reference system)	I	Integer	Unsigned Integer >= 1.	PLAI
	Tesseral Index [A/Tesseral Indexing=NOTESS]	Tesseral index for the tile contained in the module record. (layer scan reference system)	I|B	Integer Binary	Unsigned Integer.	TIND
Dimension Index (O) [O/Tesseral Index = TESS] [M/Dimension ID][A]		The order this field repeats and the number of repetitions must be correlated with the Dimension ID fields of the IREF record referenced by the RDEF record that references the LDEF record that includes this Cell module record.				DNDX
	Array Index Value [M]	An integer indicating the index along the dimension of the array corresponding to the appropriate Dimension ID Field.	I	Integer	Unsigned integer >= 0	ANVL
(-)Spatial Address (N)		Spatial address of the first cell of this module record in the Internal Spatial Reference System (Address if given here must be consistent with all other spatial referencing parameters that apply.)				SADR
(^)Attribute ID (R) [O]		Foreign identifier for Attribute Primary module record which applies to all cell values in this module record.				ATID
Cell Values (O)	(+)cell value	Contains cell data values for part or all of a stream, and for part of, all, or one or more layers, depending on the cell sequencing code. The ordering of the fields corresponds to the ordering of the Layer Definition field and the ordering of the Dimension ID field in the coresponding Raster Definition module.	A|I|R|S|B|C	Alphanum Integer Real Binary	As indicated by the Format subfield in the corresponding Data Dictionary/ Schema record.	CVLS
(continued)