Resolutions in table calculations

Tables display statistics calculated from the pixels in a given area. 

Earth Blox workflows currently run ‘on the fly’ (as opposed to running as ‘batch jobs’ in the background), this means there’s a limit to the number of pixels that can be processed in one go.

Sometimes, to ensure Table calculations complete successfully for larger areas or higher-resolution datasets, the system will need to run at a lower resolution (i.e. not the dataset’s native resolution). This means that the results may differ from those calculated in other tools.

How do I know what resolution my workflow has run at?

The resolution used for the Table calculations is shown in the Dashboard, underneath the Table’s title.

How do I change the resolution my workflow runs at?

Currently, to prevent workflows timing out, Earth Blox doesn’t allow users to set the resolution for Table calculations.

If you have needs for higher-resolution calculations, please get in touch with [email protected].

How do different resolutions work?

All image datasets in Earth Blox are formed of pyramids, which go from native resolution at the bottom of the pyramid, to the lowest resolution level at the top.

When a Table runs at a resolution other than the native resolution of the input dataset, then it will use the highest possible resolution whilst ensuring that the workflow completes successfully.

• For continuous / numeric images, a pixel value at each layer of the pyramid is the mean of the four pixels at the level below.
• For discrete / thematic images, a pixel value at each layer of the pyramid is a sample (usually the top left pixel) of the four pixels at the level below.