You are here: Appendix F: Command Line Applications and Switches > Switches Listed Alphabetically

Switches Listed Alphabetically

The following table lists all of the GeoExpress Command Line switches alphabetically. For switches used with other command line applications included in theGeoExpress installation, see mrsidgeodecode, mrsidgeoinfo, and mrsidgeometa.

Switch Value Notes
-alignpixels   Only for use with ‑reprores. Aligns the output image to an integer multiple of the output resolution. If you reproject an image and change the resolution, you may want to use this switch.
-alphalossless  

JP2 only. Specifies whether or not the alpha band should be encoded losslessly.

Default: true

-alphasource / -as string

MG4 only. Specifies how to generate the alpha channel. Accepted values are:

  • opaque or oq: All input pixels are valid

  • auto: Use the nodata value if it is set, otherwise all pixels are valid

  • <value>: Specify a transparency value for each band.

    For 8-bit and 16-bit RGB color and for grayscale images, <value> can be specified in the format RRR_GGG_BBB.

    For multispectral images, <value> is specified in the format <bandlist>@<color>

    See Alpha bands and MrSID for information on specifying per-band values

Default: auto

-aoibottom float Specifies Area of Interest offset from bottom.
-aoicoord string

Sets the coordinate system for Area of Interest to image or geo.

Default: image

-aoicr float MG3 and MG4 only. Encodes Area of Interest with a specific compression ratio.
-aoicxy float0 float1 Specifies center XY position of Area of Interest.
-aoileft float Specifies Area of Interest offset from left.
-aoilossless   MG3 and MG4 only. Encodes Area of Interest losslessly.
-aoilrxy float0 float1 Specifies lower right XY position of Area of Interest.
-aoimaskcolor string

Optional switch used in conjunction with the ‑aoimaskinner and ‑aoimaskouter switches to specify the mask color. Acceptable values are:

  • black: uses the minimum sample value

    white: uses the maximum sample value

    RRR_GGG_BBB: uses a custom 8-bit RGB color

Default: black

-aoimaskinner   Drives the interior area to a single color value (defaults to black). Cannot be used with any other AOI method (‑aoicr, ‑aoilossless, ‑aoishiftinner, ‑aoishiftouter, ‑aoimaskouter, ‑aoiweightinner, ‑aoiweightouter).
-aoimaskouter   Drives the exterior area to a single color value (defaults to black). Cannot be used with any other AOI method (‑aoicr, ‑aoilossless, ‑aoishiftinner, ‑aoishiftouter, ‑aoimaskouter, ‑aoiweightinner, ‑aoiweightouter).
-aoinumlevels uint JP2 only. Determines the number of zoom levels that the Area of Interest encoding applies to. Defaults to all zoom levels.
-aoiright float Specifies Area of Interest offset from right.
-aoishift uint JP2 only. Used in conjunction with -aoishiftinner or -aoishiftouter. Sets an optional shift value to be used with either the "shift inner" or "shift outer" Area of Interest methods.
-aoishiftinner   JP2 only. Preserves quality in the interior Area of Interest.
-aoishiftouter   JP2 only. Preserves quality in the exterior Area of Interest.
-aoitop float Specifies Area of Interest offset from top.
-aoiulxy float0 float1 Specifies upper left XY position of Area of Interest.
-aoivectoroverlay / -aoivo string

Specifies an Area of Interest using a vector overlay file. Supported vector overlay formats include:

  • Esri shapefile (*.shp)

  • MapInfo (*.tab)

  • GML (*.xml)

-aoivectorlayer / -aoivol sint Specifies the zero-based layer within a vector overlay file to use for an Area of Interest operation. The default layer is the first layer in the file.
-aoiweightinner uint JP2 only. Encodes the interior area with a given weight value.
-aoiwieghtouter uint JP2 only. Encodes the exterior area with a given weight value.
-aoiwh float0 float1 Specifies width and height of Area of Interest.
-applyRotation boolean True or false. For images that include rotation metadata, GeoExpress creates rotated output images. True is the default value. If you do not use this switch, GeoExpress creates rotated images by default.
-applyRPC   Applies the orthorectification described in the NITF RPC metadata to the image.

-as

 

See -alphasource / -as.

-bandList / -b string MG4 only. A comma-separated list specifying the bands to decode.
-bandsselection / -bands string

Specifies the bands to extract from the source image and their order in the output image. Number of bands must agree with the target colorspace (for grayscale images a single band must be specified, for RGB images 3 bands, for CMYK images 4 bands). Band numbering starts at 1. REMAINDER specifies “all the other non-alpha bands”.

Default: REMAINDER

Example: -colorspace RGB -bandselection 5,3,2

-bitsofprecision / -bop uint JP2 only. Enables you to choose how many significant bits are to be used from the samples of the source imagery. For example, an image may consist of 16-bit data values, but only eleven of those bits may be meaningful. By default full precision is used.
-blocksize / -bs sint Important: Block size affects the use of system resources. For information on block size for raster files see Advanced encoding options. For information on block size for LiDAR files, see MG4 LiDAR switches.
-blueband string Specifies the blue band component of a color composite input image file.
-blueseg uint Used in conjunction with the -blueband switch to identify which image segment of a multisegment input image to use
-bop   See -bitsofprecision / -bop.
-bs   See -blocksize / -bs.
-cbs   See -codeblocksize / -cbs.
-ccmp   See -colorcomp / -ccmp.
-ccmpseg   See -colorcompseg -ccmpseg.
-cmos   See -croppedmosaic / -cmos.
-codeblocksize / -cbs sint0 sint1

JP2 only. Specifies the width and height (in pixels) of the codeblocks used to encode the image.

Default: 64

Note: for JP2 codeblock size restrictions, see JPEG 2000 encoding.

-colorcomp / -ccmp   Identifies the input file as a formatted text file containing component bands to be used for creating a color composite image.
-colorcompseg -ccmpseg string Used in conjunction with the ‑colorcomp switch to identify which image segments to use if the input images support multiple image segments. Segments are numbered 1 through n and specified by a comma delimited list with no spaces.
-colorspace / -cs string

Specifies the target colorspace. Valid values are rgb, cmyk, gray, multi and same. Target colorspace must agree with the number of bands in the -bandsselection / -bands argument.

Default: same

Example: -colorspace RGB -bandselection 5,3,2

-colortransform  

Specifies that RGB (YIQ) Color Transform should be applied to first three bands in a multispectral image. Set to true only if first three bands are R, G and B in that order.

Default: false

-composite   Identifies the output file as a composite mosaic. The input must be a mosaic list file (with extension .mos), containing a list of MG3 or MG4 files that make up the mosaic.
-compressionratio / -cr float

Cannot be used with the ‑perbandgroupcompressionratio switch. For LiDAR files, specifying a compression ratio may cause GeoExpress to remove points to reduce the file size. Specifies how much compression is applied to an encoded file. This number is interpreted as a ratio, so a compression ratio of 20 will produce a file that is twenty times smaller than the nominal uncompressed size of the input file.

Example: ‑cr 10

-convertto8bit   Converts incoming unsigned 16-bit data to unsigned 8-bit data during encoding. The switch gets ignored for input data that is not unsigned 16-bit.
-coordspace / -coord string

Sets the coordinate system for cropping to image or geo.

Default: image (pixels).

-cr   See -compressionratio / -cr.
-cropbottom float Specifies crop region offset from bottom.
-cropcxy float0 float1 Specifies center XY position of a cropping rectangle.
-cropleft float Specifies crop region offset from left.
-croplrxy float0 float1 Specifies lower right XY position of a cropping rectangle.
-croppedmosaic / -cmos   Identifies the input file as a text file of mosaic images with cropping offsets.
-cropright float Specifies crop region offset from right.
-croptop float Specifies crop region offset from top.
-cropulxy float0 float1 Specifies upper left XY position of a cropping rectangle.
-cropvectorlayer / -cropvol sint Specifies which layer in the file is to be used for cropping.
-cropvectoroverlay / -cropvo string Specifies the overlay file to be used for cropping.
-cropwh float0 float1 Specifies width and height of a cropping rectangle.
-cs   See -colorspace / -cs.
-despeckle / -ds bool

Minimizes speckling effects in the no-data regions of newly created MG3 and MG4 and JPEG 2000 (GMLJP2) images. Accepted values are:

  • true: apply despeckling

  • false: do not apply despeckling

Default: false

-despeckleonly / -dsonly   Minimizes speckling effects in the not data regions of existing MG3 and JPEG 2000 images. Use this option to despeckle existing imagery without reencoding it.
-dsspacing uint Specifies the point spacing in the outline of the despeckling mask. Common values are 6–12. Lower values mean more points and more rigidly defined outline.
-dsthreshold uint

Specifies the despeckling threshold. All pixel values below the despeckling threshold will be used in the despeckling process. For example, with a threshold value of 10, GeoExpress treats any border pixels with a value less than 10 as no-data pixels.

Valid values are 1–127.

-eaux   Specifies that an Esri Aux file should be generated with the output.
-ecmid   Displays the Express Cartridge Manager (ECM) ID and available Data Cartridge units.
-flatten   MG3 and MG4 only. Flattens a composite mosaic.
-flattensize sint MG3 and MG4 only. Used with -flatten switch to specify a flattening tile size. Larger values may improve the speed of the flattening operation at the expense of memory.
-flushperiod / -flush uint

JP2 only. Enables codestream flushing, measured in rows of pixels. When codestream flushing is enabled, less memory may be required to encode the image. The flush period should be on the order of the strip height being used. Using the flush period should not significantly affect output image quality.

Default: 4096.

-frequencybalance float

MG3 and MG4 only. Affects the visual emphasis given to edges and flat color areas of the image. A lower setting creates more defined edges, while a higher setting creates softer edges.

Acceptable values: 0.0–10.0.

Default: 2.0.

-fromepsg sint Specifies the EPSG code describing the input image’s coordinate reference system.
-fromwkt string Specifies a text file containing a WKT that describes the input image’s coordinate reference system.
-fs string See -targetsize / -fs.
-gamma float

MG2 only. Changing the gamma value will affect the visual emphasis given to edges and flat color areas of the image. A lower setting creates more defined edges, while a higher setting creates softer edges.

Acceptable values: 0.0–10.0.

Default: 2.0.

-gmljp2coveragemetadata string JPEG 2000 (GMLJP2) only. Specifies an XML file that contains GMLJP2 coverage metadata.
-gmljp2datafile string JPEG 2000 (GMLJP2) only. Specifies a binary file that contains custom GMLJP2 data. Can only be used in conjunction with the ‑nogmljp2 option.
-greenband string Specifies the green band component of a color composite input image file
-greenseg uint Used in conjunction with the ‑greenband switch to identify which image segment of a multisegment input image to use
-h / -?   Displays a short usage message.
-help   Displays a detailed usage message.
-i   See -input / -i.
-if   See -inputformat / -if.
-ignoreworldfile / -ignorewf   Specifies that GeoExpress should ignore georeferencing from input world files.
-imageenhancement   MG2 only. Applies a dithering algorithm which may improve the visual quality of photographic imagery.
-imagesegments / -iseg string Used in conjunction with the ‑input switch to identify which image segments to use if the input image supports multiple image segments.
-input / -i string Identifies the input source file. It can be a full path name, or a path that is relative to the current working directory. Example: ‑i foo.tif
-inputformat / -if string

Identifies the input file format. Accepted formats for raster are:

  • tif or tiff: TIFF 6.0

  • tifw: TIFF 6.0 with TIFF world file

  • tifg or geotiff: GeoTIFF

  • bbb: BIP, BIL or BSQ format

  • doq: Digital Orthophoto Quadrangle (DOQ)

  • doq_nc: DOQ (no clipping)

  • ras or rast: Sun Raster

  • lan: ERDAS LAN

  • sid or mrsid: MrSID

  • jpg or jpeg: JPEG (not JPEG 2000)

  • jp2: JPEG 2000

  • bmp: Bitmap (BMP) (Windows only)

  • nitf: National Imagery Transmission Format 2.0 and 2.1 (NITF)

  • img: ERDAS Imagine

  • ecw: ECW

Accepted formats for LiDAR are:

  • las: LAS format

  • laz: LAZ format

  • sid: MrSID Generation 4 (MG4) LiDAR format

  • txt: LiDAR text file

-iseg   See -imagesegments / -iseg.
-kweight float

MG3 only. Affects emphasis of the K band for CMYK images. A higher setting increases emphasis, while a lower setting increases the consistency of color between the compressed image and the original data.

Acceptable values: 0.0–10.0.

Default: 0.25.

-localecm   Specifies the use of the locally installed Express Cartridge Manager (ECM).
-log string Directs program output to log file with specified name.
-lossless   MG3, MG4 and JP2 only. Preserves all of the pixel data of the original source image. See Lossless encoding for more information.
-maxlevels   Creates an output file with the maximum number of zoom levels that the input image supports.
-metadatafile string Specifies a text file containing user metadata tags.
-mosaic / -mos  

Identifies the input file as a mosaic list. For raster mosaics, the file must have a .mos extension. For LiDAR files, the file must have a .list extension. (Optional; if omitted, a flat mosaic file will be created if the input is a .mos or .list file.)

Do not use with ‑composite.

-ms   See -multisegment / -ms.
-msmosaic / -msmos   Identifies the input file as a text file of mosaic images with comma delimited image segment identifiers. Each line of the text file must contain the input file name, followed by a comma and then a comma delimited list of the active image segments.
-multires   MG3, MG4 and JP2 only. Enables multiresolution support for mosaic operations.
-multiresample string

Sets the resampling method for a multiresolution mosaic. Accepted values are:

  • nearest: nearest neighbor resampling

  • bilinear: bilinear resampling

  • bicubic: bicubic resampling

Default: nearest

-multiresres float0 float1 MG3, MG4 and JP2 only. Specifies the x and y resolutions for a multiresolution mosaic.
-multisegment / -ms   NITF only. Specifies the creation of a NITF file with multiple image segments.
-netecm string Specifies a network Express Cartridge Manager (ECM) to use, in the form <host name>:<port> (e.g. JohnsComputer:1234)
-nitfmetadata string Specifies a formatted text file that describes various NITF 2.1 metadata fields.
-nocolortransform   MG4 only. Specifies the omission of the default color transform for the first three bands of an image with three or more bands. Use this switch if the first three bands are not R, G and B.
-noembedschemas   JP2 only. Specifies that GMLJP2 schemas should not be embedded in the output file.
-nogmljp2   JP2 only. Specifies that GMLJP2 metadata should not be included. See About GML and GMLJP2.
-nonoptimizable   MG3 and MG4 only. Specifies that the target MrSID file cannot be optimized at a later date.
-nopltmarkers / -noplt   JP2 only. Disables packet length markers.
-noprecincts / -noprec   JP2 only. Specifies disabling precincts.
-numThreads int The number of threads that you want to use for the encoding operation. See Advanced encoding options.
-onepass   MG3 only. Specifies the use of the one-pass optimizer instead of the two-pass optimizer.
-orsrs   See -overrideSRS / -orsrs.
-otg   See -outputtilegrid / -otg.
-otm   See -outputtilemag / -otm
-output / -o string

Identifies the name of the file that GeoExpress creates. It can be a full path, or a path that is relative to the current working directory.

Example: ‑o myfile.sid

-outputformat / -of string

Identifies the desired output format of the file that is to be encoded. Accepted formats for raster are:

  • mg2: MrSID Generation 2 (MG2)

  • mg3: MrSID Generation 3 (MG3)

  • mg4: MrSID Generation 4 (MG4)

  • gmljp2: JPEG 2000 (GMLJP2)

  • jp2”: JPEG 2000 (Part I)

  • nitf”: raw NITF

  • nitfjp2”: NITF encoded as JPEG 2000(JP2)

  • tiff: GeoTIFF

Accepted formats for LiDAR are:

  • las: LAS format

  • laz: LAZ format

  • mg4: MrSID Generation 4 (MG4)

The default output format for raster and LiDAR files is MrSID Generation 4.

-outputtilegrid / -otg sint0 sint1

The number of rows and columns to split the output files into. Setting this option splits the output file into uniformly sized tiles. The output files use the base output file name appended with a numeric suffix. Only MrSID and JPEG 2000 files are accepted as input.

Example: mrsidgeoencoder ‑i foo.sid ‑o bar.sid ‑otg 2 3

-outputtilemag / -otm float Specifies the magnification of the output tiles. Valid values are between 0.0 and 1.0, where 1.0 represents the image at full resolution.
-overrideSRS / -orsrs string The EPSG or well-known text (WKT) string to use for the source file. Enter an EPSG code in quotes or specify a file that contains a WKT.
-password / -pw string MG2 and MG3 only. Encrypts image with a password. Only image data is encrypted, not metadata.
-perbandgroupcompressionratio / -pbgcr string

Cannot be used with ‑cr switch. Specifies compression ratios for groups of (non-alpha) bands in the output image. Applies to multispectral output only. See Setting per-band compression ratios for usage and examples.

-plt   See -usepltmarkers / -plt.
-porder   See -progressionorder / -porder.
-precincts / -prec string JP2 only. Specifies precinct sizes. Precincts are width-height pairs whose use may improve the performance of decode operations for certain image encodings such as those in which tiles are not used. The input format is <w1, h1, w2, h2,...wn, hn> where n is the number of zoom levels in the image. If you specify fewer than n precincts, the last one will be repeated for the remaining levels. Precinct sizes must be powers of two, except for the last one in the list, which has the lowest resolution. By default the use of precincts is enabled. Default for both width and height: 256.
-profile string

JP2 only. Specifies a predefined group of encode settings. Supported named profiles are:

  • NPJE: “NGA-Preferred JPEG 2000 Encoding” settings. The NPJE profile sets the values to approximate the preferred parameters of the National Geospatial-Intelligence Agency (NGA) for encoding images for panning and zooming at high resolution.

  • EPJE: “Exploitation Preferred JPEG 2000 Encoding” settings. The EPJE profile is optimal for low-resolution browsing among images.

  • Large: Uses optimal settings for creating large JPEG 2000 images

Default: General purpose JP2 encode settings. These are NOT the same as the GeoExpress default encode settings, which are recommended for large images. See Default JP2 settings.

-profilefile string JP2 only. Specifies path to a profile file to use for setting up encode properties. Additional properties set on the command line will override the profile settings.
-progress string Sets the appearance of progress meter. Acceptable values are none, default and timer.
-progressionorder / -porder string

JP2 only. Progression order may have a significant impact on the time and memory usage required to encode and/or decode the image. Different progression orders should be used for different target workflows. Valid values are LRCP, RLCP, RPCL, PCRL, and CPRL.

Default : RPCL

-pw   See -password / -pw.
-qualitylayers / -ql uint

JP2 only. Indicates the number of quality layers with which to encode the image. Among other things, quality layers enable better “streaming” (progressive transmission and display) in some applications.

Default: 30.

-quiet / -q   Suppresses all screen output.
-rbs   See -reproblocksize / -rbs.
-redband string Specifies the red band component of a color composite input image file.
-redseg uint Used in conjunction with the ‑redband switch to identify which image segment of a multisegment input image to use.
-reproerror float

Specifies the desired error fraction for a reprojection operation.

Acceptable values: 0.0–1.0.

Default: 0.125.

-removealpha string MG4 and JP2 only.Specifies that the alpha band should be discarded from the source image.
-removeCustomVLRs   Omit custom variable length record (VLR) metadata from LAS files. VLR metadata can include vendor-specific data, user-specified data, and more.
-reproblocksize / -rbs sint

Sets the reprojection blocking value. Use smaller values for larger images.

Default: 512.

-reproerror float

Specifies the desired error fraction for a reprojection operation.

Acceptable values: 0.0–1.0.

-repronotempfile   Specifies that GeoExpress should not use temp files for reprojection operations. By default temp files are used.
-reprores float0 float1 Specifies the X and Y resolutions for a reprojected image. You may want to use this switch in conjunction with ‑alignpixels.
-reproresample string

Sets the resampling method for a reprojection operation. Accepted values are:

  • nearest: nearest neighbor resampling

  • bilinear: bilinear resampling

  • bicubic: bicubic resampling

Default: nearest

-resample sint MG3 and MG4 only. Resamples a file by a power of 2.
-scale / -s sint Specifies the number of zoom levels, or resolution levels, that the encoded image will have. For MG2, this number must be between 3 and 9 inclusive. For MG3, any number greater than zero is supported. For JP2, the acceptable values are 1 through 12.
-sh  

See -stripheight / -sh.

-sharpness float

MG3 and MG4 only. Increasing this value increases the accuracy of rendering for sharp boundaries between different areas of an image, and reduces ringing at such boundaries.

Acceptable values: 0.0–1.0.

Default: 0.0.

-statistics / -stats  

MG2 only. Collects basic numeric statistics about the image’s samples. Data collected includes the minimum, maximum, mean, and standard deviation of the samples for each band. The metadata tags that are added to the output file are:

  • IMAGE::STATISTICS:MAX

  • IMAGE::STATISTICS:MEAN

  • IMAGE::STATISTICS:MIN

  • IMAGE::STATISTICS:STANDARD_DEVIATION

-stream64   Specifies the use of 64-bit I/O streams.
-stripheight / -sh sint

MG3, MG4 and JP2 only. Affects memory usage. Increasing this value may improve runtime performance, but at a cost of requiring more physical memory. This value should be decreased when encoding very large images. Changing the strip height does not affect the quality of the output image.

Acceptable values: Even integers from 2 to the image’s height.

Default: 12.

-targetsize / -fs string MG3 and MG4 only. Specifies the desired size of the output file in bytes. For example, ‑fs 10000 creates a file that is 10000 bytes on disk.
-tempdir string Specifies the directory used for storing temp files.
-testencode   Encodes as a test image, which does not decrement the Data Cartridge.
-textFileColumns / -tfc string For LiDAR text files, map columns to value types. See LiDAR input switches.
-textFileOffset / -tfo int The number of header rows in the text file. If you do not enter a number, GeoExpress assumes that all rows include valid values.
-textFileQuantization / -tfq float Set the quantization scale value.
-thumb int Closely related to the ‑scale switch, specifies the target thumbnail size (in pixels), which is the size of the smallest zoom level. For example, ‑thumb 32 creates a file with the number of zoom levels that comes closest to a 32 × 32 pixel thumbnail.
-tilelengthmarkers / -tlm uint

JP2 only. Specifies use of tile length markers and their size. Using tile length markers may improve decoding performance with tiled JPEG 2000 files.

Acceptable values: 1–255

Default: 255. Enter 0 to disable.

-tileparts / -tp string

JP2 only. Specifies the organization of tile parts in the codestream. Any combination of the letters R, L, and C is valid.

  • N: disable tile parts

  • R: group tiles by resolution

  • L: group tiles by quality layer

  • C: group tiles by component

Default: R

-tilesize / -ts sint0 sint1

JP2 only. Specifies the use of tiles in encoding and their size (in pixels). If enabled, the tile size must be no larger than the dimensions of the source image. Smaller tiles reduce the amount of memory required to encode the image, however the use of tiles may introduce edge artifacts.

Default: 4096 × 4096. Enter 0 × 0 to disable.

-tlm   See -tilelengthmarkers / -tlm.
-toepsg sint Specifies the EPSG code describing the output image’s desired coordinate reference system. You can also use this switch to specify an output coordinate reference system for mosaics.
-towkt string Specifies a text file containing a WKT that describes the output image’s desired coordinate reference system.
-tp  

See -tileparts / -tp.

-transparencycolor / -tpc string Set values for transparency metadata. For examples and acceptable values, see Setting transparency metadata
-ts  

See -tilesize / -ts.

-updateinplace   MG3 only. Performs a tile updating operation in place by appending tiles to the source image.
-use97wavelet   JP2 only. Specifies that the floating point 9-7 wavelet be used for encoding, instead of the default integer 5-3 wavelet. The 9-7 wavelet will not encode an image losslessly, however, it may result in a better looking image at higher compression ratios. This option is disabled by default and only available when the ‑lossless option is not specified.
-uselocallicense   Specifies the use of a standalone license.
-usenitflicense   Specifies preference for a NITF license. If no NITF license is found, GeoExpress will search for another license.
-usepltmarkers / -plt   JP2 only. Enables the use of packet length markers. Use of packet length markers may improve decoding performance. By default packet length markers are used.
-useserver string Specifies a server where GeoExpress should attempt to find a valid license. If none is found at the specified server, GeoExpress tries other servers.
-usetempfile   MG3 and MG4 only. Specifies the use of a temp file to minimize memory usage.
-version / -v   Displays version information.
-watermark string Specifies the name of the watermark image that you want to use. See Watermarks.
-weight float

MG2 and MG3 only. A higher setting increases the emphasis on the grayscale aspect of a color image, while a lower setting increases the consistency of color between the compressed image and the original data.

Acceptable values: 0.0–10.0.

Default: 2.0.

-worldfile / -wf   Generates a world file.
-writeboundsshapefile / -wbshp   Generates a shapefile indicating the boundaries of tiles that make up a mosaic.