Mosaic Generation module

Name	Caption
Input Mosaic Project	Mosaic project to process
Output Folder	Output folder
Send Email	Email notification settings
Output Channels	Output channels
Output Background Value	Output background value
Output File Type	Output file type
Output File Options	Output file options
Output Map Units	Output projection
Output Pixel Size	Output pixel size
Resampling Method	Resampling method
Area of Interest File	Area-of-interest vector file
Crop Tiles to AOI	Crop tiles to area of interest
Tile Base Name	Base name
Tile Specification	Mosaic tile specification
Height	Height of the mosaic tile, in pixels
Width	Width of the mosaic tile, in pixels
Vertical Overlap	Vertical overlap between tiles
Horizontal Overlap	Horizontal overlap between tiles
Tile File	File containing tile-definition layer
Segment Number	Vector segment in tile file
Field Name	File containing tile-definition layer
Buffer Distance	Size of buffer
Coordinate Type	Type of coordinates in script
Tile Position Transformation	Defines grid to align mosaic tiles
Blend Width	Cutline blend width
Create Source Map	Create source map
Existing Tile Rule	Rule for processing existing tile
Delete Empty Tiles	Whether to delete empty tiles

Parameter descriptions

Input Mosaic Project

The path and file name of the mosaic project file (.mos) to process.

Output Folder

The path and name of the folder to which to write the output files.

If tiled output is specified, tiles are processed by the processing nodes configured by the CATALYST Enterprise, and are stored in the specified output folder. Local copies of the tiles on processing nodes are automatically deleted. The output tile file names are generated automatically according to the Tile Base Name.

Send Email

If necessary, you can set up CATALYST Enterprise to send an email notification on job start and job completion.

With this check box selected, an email message is sent to each address specified in the Email Addresses box after the job starts and on completion.

You can specify one or more addresses, and each must be separated by a comma or a semi-colon. The email address of the user currently logged in displays by default.

Output Channels

A comma-delimited list of output channels to include in the output mosaic, listed in the order in which they are to be added.

If no value is specified for this parameter, all input channels will be added to the mosaic.

Output Background Value

The background (NoData) value to use for pixels that are not populated.

The specified background value is truncated to the range allowed by the source image data type.

When you specify one value, all channels are set to the same NoData value. If you want to specify different values for various channels, separate the values with commas. For example, to specify -32768 for channel 1 and zero for channel 2 (and any subsequent channels), enter "-32768, 0".

Output File Type

The format of the output file.

For more information on the supported file formats, see GDB-supported file formats.

Output File Options

The options to apply when creating the output file or files. The available options are specific to the file format; in each case, the default of no options is allowed.

For more information on the options available for the output file type you specify, see GDB-supported file formats.

Output Map Units

The projection of the output imagery.

The value of this parameter must be in the PCI Projection String format.

The standard definitions are:

PIXEL: Pixel and line (not for use with DEM extraction)
UTM: Universal Transverse Mercator

The value specified can be the UTM grid zone number and row, and Earth model, as follows:
```
UTM [mm] [r] [Ennn]
```
where:
- [mm] is the two-digit zone number between 1 and 60
- [r] is the zone row: a single letter between N and X for north of the equator and between C and M for south of the equator. Zone rows A, B, Y, and Z are not supported; rows I and O do not exist.
- [Ennn] specifies the Earth model, where the model number is between 0 and 19. If the Earth model is not specified, it is assumed to be E000 (Clarke 1866).
SPCS: State Plane Coordinate System

The SPCS zone number and Earth model can be specified as follows:
```
SPCS [mmmm] [Ennn]
```
where:
- [mmmm] is the four-digit zone number
- [Ennn] specifies the Earth model, where the model number is between 0 and 19. If the Earth model is not specified, it is assumed to be E000 (Clarke 1866).
LONG/LAT: Longitude and latitude

The Earth model can be specified for LONG/LAT (and other units except PIXEL), as follows:
```
LONG/LAT [Ennn]
```
If the Earth model is not specified, it is assumed to be E000 (Clarke 1866).
EPSG: European Petroleum Survey Group code

You can specify the projection by entering an EPSG code defined by the Open Geospatial Consortium (OGC). For information on the code definitions, visit epsg.org and spatialreference.org.

The EPSG code is specified using the EPSG keyword followed by an integer and separated by a colon; for example:
```
EPSG:4326
```
Most common EPSG codes are supported.
METER: Image along-row and along-column meters
FEET: Image along-row and along-column feet
You can also specify the label of a projection you define, if the projection exists in the userproj.txt file; otherwise, you must enter the projection-parameter information as a string separated by the vertical bar (|). The projection-parameter string defines 18 parameters delimited by spaces, including the following:
- Dearth
- RefLong
- RefLat
- StdParallel1
- StdParallel2
- FalseEasting
- FalseNorthing
- Scale
- Height
- Long1
- Lat1
- Long2
- Lat2
- Azimuth
- LandsatNum
- LandsatPath
- UnitsCode
For example, the projection named 'France93' can be specified, as follows:
```
LCC D350 | 0 0 3.0 46.5 44.0 49.0 700000 6600000 0 0 0 0 0 0 0 0 0 -1
```

If you do not specify a value for Output Map Units, the map unit of the input image is used for the output image. If the input data is a variety of map units, the map unit of each output image is that of its corresponding input image. In such a case, it is recommended that you specify the output map units.

You can also specify the label of a projection defined in the userproj.txt file.

Output Pixel Size

The sample size of the output imagery.

The output pixel size must be specified in the value (units) of the Output Map Units parameter; for example, when the value of Output Map Units is specified as a UTM zone, the pixel output size must be in meters. When the value is specified as Long/Lat, the pixel size must be in decimal degrees.

If you specify only one value, it defines the pixel size in both dimensions. If you do not specify any values, the resolution of the output mosaic is determined automatically by examining the resolution of the input images. The resolution occurring most frequently; that is, the mode, is used as the output resolution. If the mode is not unique, the coarsest of the tied resolutions is used.

Resampling Method

The resampling method to use during processing.

Available resampling options are:

Cubic: cubic convolution. This method determines the gray level from the weighted average of the 16 pixels closest to the specified input coordinates and assigns that value to the output coordinates. The resulting image is slightly sharper than one produced by bilinear interpolation, and it does not have the disjointed appearance produced by nearest-neighbor interpolation.
Nearest Neighbor: nearest-neighbor interpolation. This method identifies the gray level of the pixel closest to the specified input coordinates and assigns that value to the output coordinates. Although this method is the most efficient in computation time, it introduces small offsets in the output image. The output image may be offset spatially by up to half a pixel, which may cause the image to have a jagged appearance.
Bilinear: bilinear interpolation. This method determines the gray level from the weighted average of the four closest pixels to the specified input coordinates and assigns that value to the output coordinates. An image with a smoother appearance than nearest-neighbor interpolation is created, but the gray-level values are altered in the process, resulting in blurring or degraded image resolution.

Area of Interest File

A file that contains a single vector layer that defines the area to which the output mosaic is clipped.

The vector layer can contain one or more polygons.

Crop Tiles to AOI

Selected by default, this check box controls whether to crop the tiles to the area of interest (AOI) during processing.

Tile Base Name

The base name for file names of all tiles created during the mosaicking process.

Note: The value for this parameter cannot be the same as that of Input Scene File.

Tile Specification

The tiling scheme to use for the output mosaic.

Available schemes are:

Single Tile: Generates the output mosaic as a single tile.
Vector: Use when you have an existing vector-polygon layer that contains the tile definitions you want to use for the mosaic. When you select this option, you can add options for it with Tile File, Segment Number, Field Name, and Buffer Distance, respectively.
Dimensions: Creates tiles of a specific size. When you select this option, you can add options for it with Tile Height and Tile Width, respectively. When using this specification, the TileID values of the output tiles is generated using the convention <column_number>_<row_number>. For example, the upper-left tile always has a TileID of "1_1", the one immediately below is "1_2", and so on.
Script File: Use when you have a text file that defines the coordinates of each tile you want to create. When you select this option, you can add options for it with Tile File.

Height

The height of the mosaic tile, in pixels.

The union of the extents of all of the source images is divided into a series of evenly sized and abutting rectangular tiles with the specified dimension.

Only tiles that actually intersect at least one of the source images is present in the output. The tiles at the far right and on the far bottom may overhang the extents of the source images. This is done to ensure that all tiles have the same dimensions.

TileID values are generated using the convention <column_number>_<row_number>. For example, the upper-left tile always has a TileID of "1_1", while the one immediately below it is "1_2", and so on.

For example:

Width

The width of the mosaic tile, in pixels.

The union of the extents of all of the source images is divided into a series of evenly sized and abutting rectangular tiles with the specified dimension.

TileID values are generated using the convention <column_number>_<row_number>. For example, the upper-left tile always has a TileID of "1_1", while the one immediately below it is "1_2", and so on.

For example:

Vertical Overlap

The vertical overlap of each tile, in pixels.

Note: The Width parameter value is considered sacrosanct and is always honored. Thus, setting the Vertical Overlap to something other than zero causes the mosaic tile positions to be adjusted, rather than changing the tile widths.

Horizontal Overlap

The horizontal overlap of each tile, in pixels.

Note: The Height parameter value is considered sacrosanct and is always honored. Thus, setting the Horizontal Overlap to something other than zero causes the mosaic tile positions to be adjusted, rather than changing the tile heights.

Tile File

The name of the text file containing the tile-definition layer.

Each line in the text file contains five elements separated by spaces: the first two define the upper-left coordinate in the x and y dimension, respectively. The next two define the lower-right coordinate in the x and y dimensions, respectively. The last one specifies the output file name of the tile. If the file name includes an extension, the extension is removed when the value is stored as the 'TileID' attribute in the tile-definition polygon. If the file name includes a path, the entire path is transferred and appended to the output folder.

The values specified in the text file can be in one of these coordinate types:

RASEXT: Raster extents
GEOEXT: Geocoded extents
LNGLATEX: Longitude and latitude extents
RASOFFSZ: Raster offset and size
GEOOFFSZ: Geocoded offset and size

The RASEXT and RASOFFSZ coordinate types make use of pixel/line raster, as defined by the union of the extents of all input source images. If a coordinate type is not specified, it is assumed to be GEOEXT. For example:

Segment Number

In the tile file you specified, the number of the vector segment to use. If no segment number is specified, the last segment in the specified tile file is used.

Field Name

Name of the field (attribute) that has unique identifiers for each tile. The module uses the values in the field to form the names of the mosaic tile files. If no field name is specified, the attribute ShapeID is used.

Buffer Distance

The distance, in the units of the vector-layer coordinates, by which to extend the polygons. That is, when a polygon abuts another, the buffer distance extends the polygon such that the mosaic pieces overlap by the specified distance.

Coordinate Type

When Tile Specification is Script File, the type of coordinates in the script.

You can select from the following:

Geocoded Extents
Geocoded Offset & Size
Long/Lat Extents
Raster Extents
Raster Offset & Size

Tile Position Transformation

With this parameter you can define a grid where each top-left corner of a tile is aligned to one of the vertices in the grid.

You specify this parameter by entering a keyword and either two or four values. The keyword indicates the relative positioning of the values:

CORNER: indicates that the values are relative to the upper-left corner of the first pixel in the output tile
CENTER: indicates that the values are relative to the center of the first pixel

After specifying the keyword, the general form of the remaining values is:

Stride_X
Stride_Y
Ref_X
Ref_Y

These values define the position of the corner or center in the raster grid.

Of the four values, only Stride_X is required. If not specified, Stride_Y defaults to the Stride_X value, and Ref_X and Ref_Y default to zero.

In the following example, the upper-left corner of the upper-left pixel of each tile is an even 20-meter multiple from the reference point (432345.000, 5438882.000). Depending on the distance of the tile from that point, its upper-left corner coordinate could be 432345.000, 432045.000, or any other multiple, but is never 432346.000 or 432355.000.

Example:

"CORNER, 20, 20, 432345.000, 5438882.000"

If specified, this parameter is applied in all scenarios, whether the image-corner coordinates come from the input file (MFILE), ULX and ULY, or through automatic computation.

Blend Width

The perpendicular distance from the cutlines over which image blending occurs.

Image blending is to average the gray value of each pixel in the blending strip along a cutline from both overlapping input images. If no value is specified for this parameter, no blending is performed.

Create Source Map

Select this check box to create a source map on output along with the mosaic.

A source map is a polygon layer created and stored in a separate file, which contains an attribute that identifies the predominant source input image used for each pixel in the output mosaic. As images are added to the mosaic, the source image is recorded in a separate raster, which is converted to a polygon layer at the end of the process.

The polygon layer contains three attributes (fields):

SourceID: a text field that contains the SourceID of the source image.
SourceFile: a text field that includes the full GDB string including path to the source input image.
Z-order: an integer field that records the z-order of the predominate source image. The word "predominant" is used because, in the case of blending along cutlines, the source scene which had the largest contribution is the one indicated.

The source map layer is created in a file with the same name as the output mosaic file(s), but with _SourceMap.pix appended to it.

Existing Tile Rule

Select an action to perform when an output tile already exists.

Available options are:

Skip: No change is made to the existing tile and no new processing is performed. This option is useful when you do not want to modify your existing mosaic output.

Note: When an existing tile is skipped, it is not checked to see if it is empty. The tile is never deleted, regardless of the value of Delete Empty Tile.
Regenerate: Any existing tile is deleted, and then a new tile created. Unlike Skip or Update, the output is in the same projection and extents as the new polygon-tile definition.
Update: An existing tile is updated with any new information. The existing information is not overwritten; rather, the file is appended with any new information resulting from the mosaicking. Any existing georeferencing is safeguarded.

Delete Empty Tiles

Select whether to delete empty tiles. A tile is considered to be empty if all pixels in it have the value defined as NoData.

Details

General job details

Preprocessing requirements

Before running this module, the following requirements must be met to ensure the job processes successfully and produces accurate results:

The module requires, as input, a mosaic project ( .mos ) file created by the Mosaic Preparation module , the MOSPREP algorithm, or with CATALYST Professional Mosaic Tool.
Note: You can also, if applicable, use as input a source image list file ( .xml ) created with a previous version of CATALYST Enterprise .

Module details

The Mosaic Generation module automatically creates a mosaicked image using a mosaic project ( .mos ) file as input. The mosaic project is created typically by the Mosaic Preparation module . Among other options, with the Mosaic Generation module , you can define how the output mosaic will be tiled (if at all), which channels to output, and the name, blend width, and image-format type of the mosaic.

You can control the tiling of the mosaic by specifying an optional tile-definition file that defines the mosaic boundaries, tile boundaries, or both; that is, the tile-definition file can be a grid file, where each cell in the grid represents a single output tile. Alternatively, you can also specify the number of tiles to produce in the x and y directions.

With the Mosaic Generation module, you can specify the blending width (in pixels) to use when producing the image mosaic. Blending helps to reduce the appearance of seams by mixing the pixels values on either side of the cutline to achieve a gradual transition between the images. In areas containing bright or significantly different features, setting the blend width too high may cause "ghosting" or doubling of the features.

This module supports processing using GPUs and multi-core processors.

Job results

The Mosaic Generation module creates a series of output files in the specified output folder, depending on the specified options. For example, if you specified tiled output, the output folder will contain the mosaicked result in a series of tile files. The file names for the tiles are generated automatically.

In the specified output folder, the Mosaic Generation module also creates a definition folder containing a mosaic-definition file and a polygon-vector file.

Like the Mosaic Preparation module , the Mosaic Generation module can detect voids to help you assess the quality of the mosaic. A void is considered an area in the output image tiles where the pixels are NoData values. To make sure large areas around the edges of mosaics are not included, any cluster of void pixels which add up to greater than 100,000 pixels are not included by default. If voids are found, a warning message will display in the mosaic-generation child job.

Additionally, a file named <tile_ID>_Voids.pix is created with a polygon layer indicating the voids for that mosaic tile. All such void files are combined into a single file, MergedVoidFiles.pix .

If necessary, you can turn off void generation by opening the settings.py file in a text editor, and then changing the value of mosgenFindVoids from True to False , as shown in the following example:

'mosgenFindVoids': [True|False]

CATALYST Enterprise will find voids when set to True . The default value is True .

'tinyVoidWarnSize': [INTEGER]

The largest void size is determined by the INTEGER value. The default value is 100000 .

You will find the settings file in the %PROHOME%\exe\PGS\config folder of your CATALYST Enterprise installation.

In the specified output folder, the Mosaic Generation module also creates a definition folder containing a mosaic-definition file and a polygon-vector file.

Mosaic Generation module

Description

Parameters

Parameter descriptions

Details