<story><title>Rotate the world</title><url>http://www.jasondavies.com/maps/rotate/</url></story><parent_chain><item><author>BitMastro</author><text>This is just my personal preference, but I believe the naive implementation is miles ahead of the improved ones.&lt;p&gt;The improved version needs at least two movements to go to the other side of the world, doesn&amp;#x27;t follow the rotation if the cursor is too fast and worse than all, performs a gamma rotation for each non-equatorial point of the sphere.&lt;p&gt;Since we have two degrees of freedom on the screen, I expect to use them to drive the two most used rotations, and maybe have another control for the roll. In addition, we are used to have maps with North pointing up (and sometimes pointing South), so the roll is almost never used.</text></item></parent_chain><comment><author>kcorbitt</author><text>Another nice attribute the naive implementation has is path independence.  If I grab part of the globe and release it somewhere else I expect those two coordinates to determine the transform.  With the non-naive implementation I can get completely different results depending on how I wiggle my mouse on the way.  It&amp;#x27;s true that this gives me more flexibility, but I don&amp;#x27;t know... it just doesn&amp;#x27;t feel right to me.  Google Earth does it that way too, and it has always bothered me.  If I move more than a few degrees on the map I find myself either wildly gyrating my mouse to try to get back into a recognizable north-up orientation or simply clicking the compass rose to have it set things right automatically.</text></comment>
<story><title>Rotate the world</title><url>http://www.jasondavies.com/maps/rotate/</url></story><parent_chain><item><author>BitMastro</author><text>This is just my personal preference, but I believe the naive implementation is miles ahead of the improved ones.&lt;p&gt;The improved version needs at least two movements to go to the other side of the world, doesn&amp;#x27;t follow the rotation if the cursor is too fast and worse than all, performs a gamma rotation for each non-equatorial point of the sphere.&lt;p&gt;Since we have two degrees of freedom on the screen, I expect to use them to drive the two most used rotations, and maybe have another control for the roll. In addition, we are used to have maps with North pointing up (and sometimes pointing South), so the roll is almost never used.</text></item></parent_chain><comment><author>jasondavies</author><text>Thanks for the feedback!&lt;p&gt;I agree it’s not the most intuitive approach for all situations, particularly when you’re used to a North-South orientation for maps.  The rolling is perhaps made more obvious with my use of a graticule.  For this reason, I’d be interested in optionally restricting to two degrees of freedom when dragging on the globe, and the third angle could be modified when dragging outside the globe only.  So the point being dragged on the globe could still remain under the cursor where possible using this approach.&lt;p&gt;Interestingly, Google Earth uses the same approach as I do, though perhaps it seems less obvious without a graticule.</text></comment>