Resolution Filter

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Summary: This filter limits the resolutions of data that pass through it to a user-defined range of allowable resolutions.

Input:

  • Input Coverage (1 Coverage) The input data to be filtered.

Output: Coverage , Feature , Feature Collection

  • Description: A coverage that will only provide values within a specified resolution range.

Attributes:

  • Minimum Relative Resolution Set the minimum resolution BELOW the input resolution to allow data to pass through the filter. Use -1 as a value to indicate the absolute resolution should be used instead.
  • Maximum Relative Resolution Set the maximum resolution ABOVE the input resolution to allow data to pass through the filter. Use -1 as a value to indicate the absolute resolution should be used instead.
  • Minimum Absolute Resolution Set the absolute minimum resolution of data that will be allowed to pass through the filter. Use -1 as a value to indicate the relative resolution should be used instead.
  • Maximum Absolute Resolution Set the absolute maximum resolution of data that will be allowed to pass through the filter. Use -1 as a value to indicate the relative resolution should be used instead.

Details

When navigating within a ViewPoint, and the pipeline includes a Resolution Filter process, each time you zoom to a new resolution WorldView checks to see if the new resolution is within the range specifed in the Resolution Filter process. If the new resolution is within the range, the data from the pipeline appears. If the new resolution is outside the range, the pipeline returns a NULL value.

You can specify the range based on either absolute resolutions (using Minimum Absolute Resolution and Maximum Absolute Resolution) or relative resolutions (using Minimum Relative Resolution and Maximum Relative Resolution). If you are using the absolute resolution, be sure to set both of the relative resolution values to -1. Similarly, if you are using the relative resolution, be sure to set both of the absolute resolution values to -1.

Note that a data source has an inherent ideal resolution, and that WorldView automatically adds a default resolution filter when visualizing a pipeline. This default resolution filter specifies a maximum relative resolution of 5 and a minimum resolution of 10. This would mean that if a data source had an ideal resolution of 25, for example, WorldView would never display data for that data source above resolution 30 (25+5), or below resolution 15 (25-10).

If you want you can add another Resolution Filter process to the data pipeline, and WorldView will apply it as well as the default resolution filter. Since the default resolution filter is still applied you can't use the additional resolution filter to extend the range of resolutions for which WorldView will return data, but you can use the additional resolution filter to further restrict the range of resolutions.

Example 1 - Using an absolute resolution range

Suppose you are only interested in seeing the data from a particular data source between resolution 18 and resolution 20. You would set the Minimum Absolute Resolution attribute to 18 and the Maximum Absolute Resolution attribute to 20. At resolutions below 18 or above 20 no data from the pipeline would appear.

Example 2 - Using a relative resolution range

Suppose you don't know the ideal resolution of a data source, but you know that it becomes pixelated at higher resolutions. You could set the Maximum Relative Resolution attribute to 2. This would limit the data pipeline to only providing data at resolutions 2 beyond its ideal resolution.

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