Friday, January 31, 2014

v32: shared metadata

From version 32, you are now able to create a custom metadata vocabulary and share/reuse it among your data hubs (instead of having to keep multiple copies over many hubs).

As an example, we put following JSON contents into a text file to define a metadata vocabulary:

{
vocabulary:{
    "epigenetic mark":{
        "dna methylation":["aa","bb","cc"],
        "histone mark":["dd","ee"],
        },
    "rna-seq":{
        "mRNA":["aa","ee"],
        "small RNA":["dd","bb"],
        },
},
tag:"My shared metadata",
}

To make it a shared metadata, put the file on a web server. Now the file is addressable by its URL:

http://vizhub.wustl.edu/hubSample/hg19/t/metadata


To share this metadata with a JSON data hub, add following JSON content into the hub:


{
type:"metadata",
vocabulary_file_url:'http://vizhub.wustl.edu/hubSample/hg19/t/metadata',
show:["epigenetic mark","rna-seq"],
},

The hub file can be found at this URL: http://vizhub.wustl.edu/hubSample/hg19/t/hub1withsharedMD



The shared metadata vocabulary will be in use.

Another hub which also shares this metadata vocabulary is here: http://vizhub.wustl.edu/hubSample/hg19/t/hub2withsharedMD

You can see how the shared metadata works by load this hub following the first one.


When a shared metadata is loaded, you can see the vocabulary by right-clicking term names on top of metadata color map, and choose "Add metadata terms" option:



The custom metadata is indicated by a tag name and orange background color:


Click the tag to get more information about this vocabulary: