Compute Mosaic Candidates (Data Management)

Summary

Finds the image candidates in a mosaic dataset that best represent the mosaic area.

Densely overlapped images are necessary in many projects but may make it difficult to determine which images in a mosaic dataset should be used in an analysis. This tool finds the optimal images based on areas of maximum overlap and area excluded.

The input mosaic dataset will include a new Candidate field in the mosaic dataset footprint table. This field determines which images will be used in certain operations, such as color balancing, seamline generation, ortho mapping, and mosaic methods.

Usage

• This tool is useful when working with orthomosaic projects that may include overlapping UAV or UAS data in a mosaic dataset. In these cases, finding the optimal images in the mosaic dataset will generate a good block adjustment result for the orthomosaic.

• Use this tool before running the Build Seamlines or Color Balance Mosaic Dataset tool. The Candidate field in the mosaic dataset footprint table determines which images will be used in these other tools.

• The Candidate field in the mosaic dataset footprint table can have a value of 0, 1, or 2. A value of 0 means that the image is not an appropriate candidate. A value of 1 means that this image is an appropriate candidate according to the tool output, and it will automatically be used by algorithms that use the Candidate field. A value of 2 can be manually added so the selected image will automatically be used by algorithms that use the Candidate field.

• The value in the Candidate field can be manually edited to include or exclude specific images.

Parameters

Dialog

Label	Explanation	Data Type
Input mosaic dataset	The input mosaic dataset with densely overlapped images.	Mosaic Dataset; Mosaic Layer
Maximum Area Overlap (Optional)	The maximum amount of overlap between the mosaic dataset and the footprint of each image in the mosaic dataset. If the percentage of overlap is greater than this threshold, the image is excluded since it will have too much redundant information. The percentage is expressed as a decimal. For example, a maximum overlap of 60 percent is expressed as 0.6.	Double
Maximum Area Loss Allowed (Optional)	The maximum percentage of area that can be excluded by the candidate images. After the tool finds the best candidate images based on the Maximum Area Overlap parameter value, it checks whether the maximum excluded area is below the threshold specified. If the excluded area is greater than the specified threshold, the tool will add candidate images to fill in some of the voids that were missing. These excluded areas will typically be along the border of the mosaic dataset. The percentage is expressed as a decimal. For example, a maximum excluded area of 5 percent is expressed as 0.05.	Double
Maximum Obliqueness Angle of Image (Optional)	The maximum image obliqueness angle that will be used to filter images. Any image with an obliqueness angle larger than this value will not be used as a candidate. This parameter is measured in degrees. The default value is 15.	Double

Derived Output

Label	Explanation	Data Type
Derived Mosaic Dataset	The updated mosaic dataset.	Mosaic Dataset; Mosaic Layer

Python

arcpy.management.ComputeMosaicCandidates(in_mosaic_dataset, {maximum_overlap}, {maximum_area_loss}, {maximum_obliqueness_angle})

Name	Explanation	Data Type
in_mosaic_dataset	The input mosaic dataset with densely overlapped images.	Mosaic Dataset; Mosaic Layer
maximum_overlap (Optional)	The maximum amount of overlap between the mosaic dataset and the footprint of each image in the mosaic dataset. If the percentage of overlap is greater than this threshold, the image is excluded since it will have too much redundant information. The percentage is expressed as a decimal. For example, a maximum overlap of 60 percent is expressed as 0.6.	Double
maximum_area_loss (Optional)	The maximum percentage of area that can be excluded by the candidate images. After the tool finds the best candidate images based on the maximum_overlap parameter value, it checks whether the maximum excluded area is below the threshold specified. If the excluded area is greater than the specified threshold, the tool will add candidate images to fill in some of the voids that were missing. These excluded areas will typically be along the border of the mosaic dataset. The percentage is expressed as a double. For example, a maximum excluded area of 5 percent is expressed as 0.05.	Double
maximum_obliqueness_angle (Optional)	The maximum image obliqueness angle that will be used to filter images. Any image with an obliqueness angle larger than this value will not be used as a candidate. This parameter is measured in degrees. The default value is 15.	Double

Derived Output

Name	Explanation	Data Type
out_mosaic_dataset	The updated mosaic dataset.	Mosaic Dataset; Mosaic Layer

Code sample

ComputeMosaicCandidates example (Python window)

This is a Python sample that finds the candidates with less than 60 percent overlap and less than 5 percent of the area excluded.

Import arcpy
arcpy.ComputeMosaicCandidates_management("c:/data/fgdb.gdb/md", 0.6, 0.05)

Environments

Current Workspace, Parallel Processing Factor, Scratch Workspace