Hey Adam,

On Jul 4, 2012, at 3:44 PM, Adam Estrada wrote:

> Hi Ross,
> 
> We need to keep in mind that there are lots and lots of crs's that are not 
> represented in decimal degrees. Therefore, it would be beneficial to accept 
> any values. Proj4[1] is a projection library that transforms geographic 
> coordinates (latt/long) in to cartesian coordinates and visa versa. We should 
> look at using that. Its MIT licensed too which I believe is cool. Mattmann, 
> what say you?

+1, I think we should definitely look at Proj4J. 

Scope out my other email too.

Cheers,
Chris

> 
> 
> 
> On Jul 4, 2012, at 6:06 PM, Ross Laidlaw wrote:
> 
>> Hi everyone,
>> 
>> I've been looking into developing some unit tests for the core classes
>> in sis-core.  While developing the unit tests, I noticed that the
>> LatLon constructor can accept any valid double values for its latitude
>> and longitude arguments.  Is this ok or should there be some
>> constraints, checks or conversions performed on the arguments to the
>> constructor?
>> 
>> In the LatLon class there's a 'getNormLon()' method that returns the
>> longitude attribute normalized to a value between -180.0 and 180.0.
>> This implies that it's ok for the constructor to accept longitude
>> arguments outside this range and for the longitude attribute to have a
>> value outside this range.
>> 
>> On the other hand, it looks like the getShiftedLat() and
>> getShiftedLon() methods assume that the latitude and longitude
>> attributes for a LatLon object should be within the standard ranges
>> (i.e. between -90.0 and 90.0 for latitude and -180.0 to 180.0 for
>> longitude).
>> 
>> So I was thinking - perhaps we could accept any values for the
>> constructor arguments, but then normalize them in the constructor so
>> that the attributes are stored as normalized values.  Alternatively,
>> we could update the getShiftedLat() and getShiftedLon() methods to
>> check/normalize the attributes before shifting them.
>> 
>> Any thoughts?  Apologies if I've completely misunderstood any of these 
>> methods!
>> 
>> Ross
> 


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Chris Mattmann, Ph.D.
Senior Computer Scientist
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 171-266B, Mailstop: 171-246
Email: [email protected]
WWW:   http://sunset.usc.edu/~mattmann/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Adjunct Assistant Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA
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