The DAS Registry^{V2.8.5 02 09 2010}

The Biological Distributed Annotation System Registry- Search (New Interface)

This page is part of the DAS 1.53E specification

maxbins - restricting the maximum number of features

A DAS client can do a standard DAS - features request and add the parameter

 
 maxbins=X
 
 

where X is the number of pixels used for display on the DAS client.

One of the core principles behind DAS is that the servers are rather simple, whereas all intelligence is located on the DAS client side, which manages to provide a clever integration of the data obtained from various DAS servers. The maxbins extension adds a bit of intelligence to the DAS server side, for performance reasons with large number of features.

This extension is useful for DAS servers that return large numbers of features. The maxbins parameter gives the server an idea of how big the display on the client side will be and then can choose the right resolution for the returned features. If a whole chromosome is being displayed it does not make sense to reply thousands of features of size 1 base. Instead the server might group features together, show only the features with the highest scores. The scaling is depending on the actual biological data, hence DAS should not enforce a certain behaviour regarding that.

Ensembl adds the maxbins parameter by default to all DAS requests. If a server does not support this parameter, it should simply respond with all features for the requested segment.