Today we posted a small update to the API.  The change includes one new method that provides a binary download of the expression energy volume.  This method differs from the orginal expression energy download in three ways--

• The data includes an value for every voxel in the volume.  For voxels that were not mapped, the value is -1. The original method returned a sparse volume which only contained values where the expression energy was greater than 0.
• The new volume format does not include coordinates for each voxel.  Rather it is a set of four-byte sagittaly-arranged floating point values.  The original format included (x,y,z) coordinates for each value.
• The data is in binary format.  The original method used text.

The original method is still and will continue to be supported.  Here's an example of the volume in the orginal format: http://www.brain-map.org/aba/api/expression/75144618.sva And here in the new format: http://www.brain-map.org/aba/api/expression/75144618.bva