एक जीपीएस (GPS) उपग्रह द्वारा पृथ्वी का एक चक्कर पूरा करने में लगभग कितना समय लगता है?

Small registration marks printed on the edges or corners of aerial photographs for orientation are known as:

The Polyconic projection was originally designed and introduced by whom?

Consider the following statements regarding the Open Series Maps (OSM) of the Survey of India: (A) These are based on the WGS-84 datum. (B) These maps are prepared on the International Projection. (C) These are available in both hard copy and digital formats. Select the correct answer from the options given below: