GXL-Satellite Mosaic Generation. Training Guide

Transcription

1 GXL-Satellite Mosaic Generation Training Guide Version 1.0 June 20, 2016

2 Copyright notice 2011 PCI Geomatics Enterprises, Inc. All rights reserved. Software copyrighted by: PCI Geomatics Enterprises, Inc. 90 Allstate Parkway, Suite 501 Markham, Ontario L3R 6H3 CANADA Telephone number: (905) The Licensed Software contain material that is protected by international Copyright Law and trade secret law, and by international treaty provisions, as well as by the laws of the country in which this software is used All rights not granted to Licensee herein are reserved to Licensor. Licensee may not remove any proprietary notice of Licensor from any copy of the Licensed Software. RESTRICTED RIGHTS Canadian Government Use, duplication, or disclosure is subject to restrictions as set forth in Public Works and Government Services Canada Supplemental General Conditions Licensed Software U.S. Government Use, duplication, or disclosure by the Government is subject to restrictions set forth in subparagraph (b)(3) of the Rights in Technical Data and Computer Software clause of DFARS or subparagraph (c)(1) and (2) of the Commercial Computer Software-Restricted Rights clause at 48 CFR as amended, or any successor regulations thereto. The Government agrees: (a) if the Licensed Software is supplied to the Department of Defense ( DoD ), the Licensed Software is classified as Commercial Computer Software and the Government is acquiring only RESTRICTED RIGHTS in the Software as that term is defined in Clause (c)(1)(ii) of the DFARS (48 CFR ); and (b) if the Licensed Software is supplied to any unit or agency of the United States Government other than DoD, the Government s rights in the Licensed Software will be as defined in Clause (c)(2) of Supplement to the FAR. PCI, PCI Geomatics, PCI and design (logo), Geomatica, Committed to GeoIntelligence Solutions, GeoGateway, FLY!, OrthoEngine, RADARSOFT, EASI/PACE, ImageWorks, GCPWorks, PCI Author, PCI Visual Modeler, and SPANS are registered trademarks of PCI Geomatics Enterprises, Inc. Sentinel is a registered trademark of SafeNet, Inc. Copyright (c) Info-ZIP. All rights reserved. InstallAnywhere is a registered trademark of Macrovision Corporation. All other trademarks and registered trademarks are the property of their respective owners. PCI Geomatics and Geomatica are registered trademarks of PCI Geomatics. The information in this document is subject to change without notice and should not be construed as a commitment by PCI Geomatics. PCI Geomatics assumes no responsibility for any errors that may appear in this document.

3 Contents Copyright notice... ii 1. Introduction Workflow and data flow Generating an image mosaic Performing Quality Control Reviewing the output tiles Reviewing cutlines Reviewing the output source maps... 8 GXL-Satellite Mosaic Generation i

4 Acknowledgement PCI Geomatics acknowledges Blackbridge Geomatics for providing the sample data used in this text book. The data used in this training manual remain the property of Blackbridge Geomatics, Inc. The user of this manual is granted a non-transferable right to use the data/imagery contained in the documents in a non-commercial manner. The user may not, and may not permit others to, use, reproduce, or distribute, in whole or in part, the material in the documents. ii GXL-Satellite Mosaic Generation

5 List of figures Figure 1: The GXL-S workflow... 1 Figure 2: Geomatica Focus displaying output mosaic tiles... 5 Figure 3: Mosaic tiles with adaptive image enhancement... 6 Figure 4: Geomatica Focus displaying mosaic cutlines... 7 Figure 5: Zoom in to examine cutlines... 7 Figure 6: Geomatica Focus displaying source maps... 8 Figure 7: Attribute table for sample source map... 9 Figure 8: Viewing source map attributes in Focus... 9

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7 1. Introduction The PCI GeoImaging Accelerator Satellite (GXL-S) is a powerful and specialized processing system that allows you to efficiently use distributed processing techniques, in combination with modern computer hardware and automated workflows, to produce high-quality image mosaics comprised of satellite imagery from various sensors. The GXL Mosaic Generation module allows you to automatically generate a final, orthorectified image mosaic using the source image list XML file generated by the GXL Mosaic Preparation module as input. The module allows you to define how your mosaic will be tiled, which channels to output, the name of the mosaic image, and the mosaic image format type. 1.1 Workflow and data flow Error! Reference source not found. illustrates the standard workflow for processing satellite imagery with the GXL system. Figure 1: The GXL-S workflow GXL-Satellite Mosaic Generation 1

8 1.2 Generating an image mosaic To begin the mosaic generation process, you must first create and submit a GXL Mosaic Generation job. To create a GXL Mosaic Generation job: 1. From the JPS Administrator main Navigation Bar, click Job Types. 2. From the list of available jobs to submit, select GXL Mosaic Generation. The job submission page for the module appears. The following table briefly describes the workflow parameters for this module. For more detailed information about each parameter, refer to the Module Reference Web Help accessible through the JPS Administrator (Help). Workflow Parameter Mandatory / Optional Description Input Scene File Mandatory Specifies the path and file name of the source image list XML file generated by the GXL Mosaic Preparation module. Important: The name of the source image list XML file cannot be the same as the value specified in the Base Name parameter. Output Folder Mandatory Specifies the path to the directory that will contain the output mosaic products. If tiled output is specified, tiles are processed by the processing nodes configured by the JPS, 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 Base Name. Base Name Mandatory Specifies the base name for the output files. The base name will be used for file names for all tiles generated during the mosaicking process. Important: The Base Name cannot be the same as the Input Scene File name. Resampling Type Mandatory Specifies the resampling method to use during orthorectification. Available resampling options are: CUBIC (cubic convolution): NEAR (nearest neighbor): BILIN (bilinear interpolation): Output Channels Optional Specifies the output channels to include in the mosaic, listed in the order in which they are to be added. Tile Specification Optional Optionally specifies the tiling scheme to use for the output mosaic. 2 GXL-Satellite Mosaic Generation

9 Workflow Parameter Mandatory / Optional Description Available tiling schemes are: [blank]: Generates a single output mosaic tile for the mosaic. Vector: A vector polygon containing the tile definitions Dimensions: Creates tiles of the specified size Script File: A text file defining the coordinates of each tile Tile Specification Extra Options Optional Defines additional options for the specified Tile Specification. Blend Width Optional Optionally specifies the blend width to use to blend pixels along the cutlines in the output mosaic. Output File Type Mandatory Specifies the output file format type. Supported file formats are: Output File Options Optional PIX: PCIDSK file format TIF: Tagged Image File format JP2: JPEG2000 file format NOTE: When selecting an output image format, consider the estimated size of the output file. Some format standards do not allow file sizes greater than 2GB. Indicates specific file format characteristics; for example, tiled, jpeg compression etc. Create Source Map Optional Creates an output source map along with the mosaic. A source map is a polygon layer that contains an attribute identifiing the input image used for the area within each shape. Existing Tile Rule Optional Indicates system behavior in the event of a preexisting output tile. Three possible rules are available: SKIP: the existing tile is left unchanged and no new processing is performed for this tile. REGEN: The existing tile will be deleted and a new file created. UPDATE: existing tiles will be updated. The existing information will not be cleared, but any new information from the mosaic process will be written to the tile. The existing file's georeferencing will be respected. Delete Empty Tile Optional Indicates system behavior for empty tiles. A tile is considered empty if all of the pixels in it have GXL-Satellite Mosaic Generation 3

10 Workflow Parameter Mandatory / Optional Description the value defined as No Data. Available options are: NONE: no tiles will be deleted. ALL: all empty tiles are deleted. 3. Define the following parameters for the RapidEye sensor: Click Submit Job. a. Enter the Input Scene File: O:\California\Output\Mosaic\Mosprep\Cal.xml b. Enter the Output Folder: O:\California\Output\Mosaic\Tiles c. Enter the Map Units: UTM 11 S D000 d. Enter the pixel size: 5,5 e. Enter the Tile Base Name: California f. Set the Tile Specification to: Dimensions g. Enter the Tile Specification Extra Options: 10000, The GXL Mosaic Generation module reads the source image list XML file and identifies all scenes to be mosaicked. Using the tile specification option you selected, the module spawns a set of child jobs, each representing an output tile that comprises the mosaic. Each processing node/server generates a tile (or more) in parallel with the other processing nodes/servers, until all tiles are generated for your mosaic area. Results After successfully executing the GXL Mosaic Generation module, the output directory will contain a series of mosaic tiles and source maps associated with each tile. If you find that the output file size for the tiles are too large, you may reprocess the mosaic through the GXL Mosaic Generation module using a smaller output tiling size (DIMENSIONS). Doing so will produce more tiles with smaller output file sizes. 1.3 Performing Quality Control The quality of the output image mosaic tiles is dependent upon the quality of the mosaic preparation process. Your output image mosaic should look identical to the mosaic preview you previewed (or edited) in the Mosaic Tool. If there are any issues with the output mosaic related to color balancing, cutline selection, etc., you can return to the Mosaic Tool or the GXL Mosaic Preparation module and make your changes there Reviewing the output tiles Each tile generated has a file name defined by the base name specified during the setup of the GXL Mosaic Generation module, as well as the tile ID. The ID with the suffix _1_1.PIX represents the tile in the upper-left most corner of the area of interest; the tile with the ID suffix _2_3.PIX is the tile in the lower-right most corner of the area of interest. 4 GXL-Satellite Mosaic Generation

11 To view output mosaic tiles in Geomatica Focus: 1. Open Geomatica Focus. 2. From the Focus menu, select File > Open to navigate to the output Mosaic\Tiles directory. Select all the mosaic tile images, and click Open. Figure 2 shows a sample mosaic with four mosaic tiles, displayed in Geomatica Focus. Figure 2: Geomatica Focus displaying output mosaic tiles 3. To adjust the image enhancements, right-click on each tile and select Enhance > Adaptive. The resulting mosaic appears more pleasing to the eye, as shown in Figure 3. GXL-Satellite Mosaic Generation 5

12 Figure 3: Mosaic tiles with adaptive image enhancement Reviewing cutlines To inspect the quality of the mosaic cutlines, you can load all the cutlines generated by the GXL Mosaic Preparation module and view the resulting mosaic in those regions. To view output mosaic tiles in Geomatica Focus: 4. Open Geomatica Focus. 5. From the Focus menu, select File > Open to navigate to the output Mosaic\Cutlines directory. Select all the mosaic cutlines, and click Open. Figure 4 shows a sample mosaic with all the generated cutlines, displayed in Geomatica Focus. 6 GXL-Satellite Mosaic Generation

13 Figure 4: Geomatica Focus displaying mosaic cutlines 6. Zoom in to various regions of the mosaic in which a cutline is displayed to visually assess the quality of the cutline generation and the color balancing in the mosaic. Figure 5: Zoom in to examine cutlines GXL-Satellite Mosaic Generation 7

14 1.3.3 Reviewing the output source maps In addition to the output tiles and cutlines, the GXL Mosaic Generation module generates source maps for each output tile. These source maps are vector polygon files that provide a list of the source images that comprise each pixel in the output mosaic tiles. These maps can be loaded into Geomatica Focus for review. To view output mosaic tiles in Geomatica Focus: 1. Open Geomatica Focus. 2. From the Focus menu, select File > Open to navigate to the output Mosaic\SourceMap directory. Select all the source map files, and click Open. Figure 2 shows a sample mosaic with all the generated source maps, displayed in Geomatica Focus. Figure 6: Geomatica Focus displaying source maps Each source map file covers the extent of the tile that it references. By reviewing the attribute table for a particular polygon, you can view the source image for that polygon in its respective mosaic tile. Right-click a source map from the Maps tab and select Attribute Manager. The Attribute Manager for the selected source map opens. For example, XREF shows the attribute manager for the source map file for SPOT5_1_1.PIX. 8 GXL-Satellite Mosaic Generation

15 Figure 7: Attribute table for sample source map Use the Focus vector selection tools to select a shape in the source map (representing a block of pixels originating from a source image). The selected shape is highlighted in the Attribute Manager, as shown in Figure 8. The Attribute Manager also displays the name of the file from which that block of pixels originated, as well as the order in which it was added to the mosaic. Figure 8: Viewing source map attributes in Focus When you complete the necessary modifications to the mosaic, save the source map, cutline, or mosaic tile. Your mosaic image is now complete. If desired, you can update your mosaic with new imagery, using the GXL Mosaic Update Generation module. GXL-Satellite Mosaic Generation 9