Location attribute for nodes

[squeetus]

We are planning to use nodes' 'location' attribute to represent coordinates in cartesian space.

As such, we need to add the following:

• New, semantically-irrelevant default values for location (perhaps positive infinity?) for x and y elements
• Conditionally add location attributes to the JSON only if they differ from the default values (make a comparison for each node representation considered)

[krs-world]

David, I have modified the Bridges Element::getRepresentation() to only push the location attribute if they are not their default values (POSITIVE_INFINITY). I did some testing and it seems to work. Test it out..

  -- krs

[squeetus]

As discussed, we currently need to add:

• a top-level attribute in the JSON to indicate the coordinate space. We could call this 'coordspace' or something similar, and it can include options such as 'cartesian' and 'latlong.' This will allow the server to differentiate location usage for each assignment. (we can also get rid of the 'version' attribute in the JSON). We need to add the coordspace attribute any time at least one location attribute is used (so not for every assignment), and maybe we can default to using cartesian space without having to set it manually? Let me know what you think.

• a way to allow integer values for locations. They can all be cast to double, but we want the option to be available to enter integer values as well as doubles.