Mosaic dataset seamlines
Seamlines are used when mosaicking the raster data in a mosaic dataset. They are used instead of footprints to define the line along which the rasters in the mosaic dataset will be mosaicked when using the Seamline mosaic method.
When using the Seamline mosaic method, the mosaicked image will not change as you move around the image, as can happen when using mosaic methods like Closest To Center. Also, if you create seamlines, you can ensure the mosaicked image is the best possible mosaic by editing the seamlines to be sure buildings are not along the line and that the seam between images is not obvious.
To create seamlines for a mosaic dataset, you use the Build Seamlines tool. By default, the seamlines are generated using the North-West mosaic method, where the image in the north-west is displayed on top. The distance between the center of each image is calculated in determining the north-west image. The diagram below represents the mosaicking order using the North-West mosaicking method.
You can also choose to create the seamlines using the Closest To Viewpoint or By Attribute mosaic methods. Once the seamlines are built, a Seamline layer will be present in the table of contents each time you add the mosaic dataset to ArcMap.
Seamlines are like footprints: there is one polygon representing the contents of each image to use when creating the mosaicked image. If you have your own seamline (polygon) file, you need to first run the Build Seamline tool to establish the framework for the seamlines. You can then use the Import Mosaic Dataset Geometry tool to replace the seamlines with your own.
To remove all the seamlines from a mosaic dataset, right-click the mosaic dataset in ArcCatalog or the Catalog window and click Remove > Remove Seamlines.