What is the difference between the sky as seen from latitude 30 degree north?
... and the sky as seen from where else . . .
If you meant the degree difference, it is a 30 degree latitude difference between 30 degrees north latitude and 0 degrees longitude. If you meant the difference in features: 0 degrees latitude is longer than 30 degrees north latitude. 30 degrees north latitude is located in the northern hemisphere while 0 degrees latitude is located in the middle of the northern and southern hemispheres.
What would be the longitude and latitude for a place that is halfway between the equator and the north pole?
The difference between latitude and longitude is that latitude refers to a location point's distance that is either north or south of the equator and longitude refers to a specific point's distance that is either east or west of the prime meridian. The prime meridian is the longitude line that has zero degree and passes near London, United Kingdom.
Why is the distance between each degree of latitude greater than the distance between each degree of longitude?
At the equator, a degree of longitude is the same distance as a degree of latitude. One minute of latitude is equal to one nautical mile, so one degree equals 60 nautical mile. As you go north or south, the lines of longitude converge, coming together at the poles. So the distance (in nautical miles) of one degree of longitude is equal to 60 times the cosine of the latitude.
Lateral direction runs from east to west and longitudinal direction runs from north to south. Latitude lines are parallel and equidistant from each other. The distance between latitude lines is approximately 69 miles. The equator is at 0 degree latitude. Longitude lines are known as meridians and converge at the poles. Longitude lines are widest at the equator.