model  ppi (pixels per inch )  ppcm (pixels per cm )  resolution typical viewing distance (in / cm)  pixels per degree (ppd)
0       iphone 4 / 4s and ipod touch (4th generation)                     326                    128      960640                        inches (cm)                       57
1  iphone 5 / 5s / 5c and ipod touch (5th generation)                     326                    128     1136640                        inches (cm)                       57
2            ipad ( 3rd / 4th generation / ipad air )                     264                    105    20481536                        inches (cm)                       69
3                          ipad mini (2nd generation)                     326                    128    20481536                        inches (cm)                       85
4                  macbook pro with retina display 15                     220                     87    28801800                        inches (cm)                       77

Table as JSON:
{"model":{"0":"iphone 4 \/ 4s and ipod touch (4th generation)","1":"iphone 5 \/ 5s \/ 5c and ipod touch (5th generation)","2":"ipad ( 3rd \/ 4th generation \/ ipad air )","3":"ipad mini (2nd generation)","4":"macbook pro with retina display 15"},"ppi (pixels per inch )":{"0":326,"1":326,"2":264,"3":326,"4":220},"ppcm (pixels per cm )":{"0":128,"1":128,"2":105,"3":128,"4":87},"resolution":{"0":960640,"1":1136640,"2":20481536,"3":20481536,"4":28801800},"typical viewing distance (in \/ cm)":{"0":"inches (cm)","1":"inches (cm)","2":"inches (cm)","3":"inches (cm)","4":"inches (cm)"},"pixels per degree (ppd)":{"0":57,"1":57,"2":69,"3":85,"4":77}}