The controls on this page allow you to modify a WCPS query which is sent to the server when you hit the Execute button.
The X and Y sliders can be used to select a geographic bounding box to subset the portion of the image displayed. (Or you can directly enter the coordinates in the text boxes.)
The Z slider can be used to highlight a certain depth range (in red).
This illustrates both the processing that can be done to present non-image numerical data in a visual way and reducing the size of data that is actually retrieved over the web from the full source data set size.
A query on the full extent of the data set can take up to 25 seconds to process.
A query on a subset of the data such as should take just a few seconds.
The data here is a 2D square grid coverage with a single thickness value for each grid cell. The X and Y coordinates are British National Grid Eastings and Northings. It is 11878 x 24128 grid cells in size which uses approximately 1.2Gb. The thickness values go from 0m to 240m. Unlike the DTM there is an explicit no data value (most negative value representable in a float ~ -3.4x1038).
The WCPS query has the following components: