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Shyam Mohan

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  1. Shyam Mohan

    Map Tie Error in LROC Images

    Hello All, Consider the LROC Product ID M181345381RC.The details of the latitude and longitude are as follows, Maximum Latitude 30.2 Minimum Latitude 27.72 Westernmost Longitude 333.81 Easternmost Longitude 334.13 The above values have a precision of only two decimal points which means a maximum of 0.005 deg error is possible. If we assume that that the angular resolution of moon is 30Km/deg(approx) then there can be a map tie error of 30000*0.005=150 meters in position. Is there any other source of information with higher precision? If not, can we assume that 150m is the maximum map tie error expected from LROC products? Thank You, Shyam.
  2. Shyam Mohan

    Why is there a flip in LROC Images?

    Thank you all. Your support is valuable.
  3. Shyam Mohan

    Why is there a flip in LROC Images?

    Thank you for a quick response. I understand that the left and right of an image is not always the west and east of real direction and it depends on the depends on the flight direction of the satellite. I expect one image to be a180deg rotation of the other if the flight direction changes. For example if the flight direction is such that the camera moves from south to north then I might get a vertically long image with the up direction being the north, down direction being the south, right direction being east and left direction being west. If the flight direction changes and the camera moves from north to south then the up direction of the vertically long image is south, down direction is north, right direction is west and left direction is east. Essentially if one image is flipped both left and right and up and down then I should get the other image. However this was not observed in the images that I am referring to (cropped images are attached). If you compare the LROC quickmap with the product M1106080949LC then the up and down directions remain same without any flip. You will notice that there is a flip in the left and right directions only. This is strange unless the camera itself stores the image in a flipped manner along one direction only. Could you please help me in understanding this problem?
  4. Consider an image downloaded from the Lunar Orbital Data Explorer (http://ode.rsl.wustl.edu/moon/indexProductSearch.aspx). If you filter the LROC-CDRNAC product by the below location then you will get the image with the product ID M1106080949LC. Minimum Lattitude : 29 and Max Lattitude : 30. Minimum Longitude : 334 and Max Longitude : 335. However if you compare the above image with the LROC image in the below link then you will realize that the images do not match and there is a flip along the vertical line. http://quickmap.lroc.asu.edu/?layers=NrBsFYBoAYchGSJQBYF3gXSaUdZY4Ds%2BC2YAHKYWAJzXlGzNlJGIs0BMttVn5HrwaZBoLtSTAuoDhnIBmaF37ykKpSPLx4UAuhA60ApDpJyaS6HIKCK7Bqc0ng8BTdauFCx17wu3EgCFehcNCTD7CLVXFBZbdQpQUPlRJAUuaP0QDI8sNOAlENJoADooHOg4rXToBWN8cqkivVTFOp9OZuUU5nL250bwAY8y4dqMkv6ChXFJHNkprnHC0E6hxVQpldnWvuGZutV97tntgaCNmaIG7MKidb7ddq5bmFLn2uWpz8Llf0avyUXEuTwOiiIALuCiIe08MOO8KIvXhFHiqLyigoWVRj1Rb3y5Di6MQOWELmBeMsyhxhPSoFBBlWUPhoER3HsJM2KMsTF8MMx6SItNERNe82AKC4eLKCjFcNlYpZZVooqQKHAVKkGpF6vACum7XgPO60BZ1Kq-OgdSt1t84C4XMSa18KggrqSBLsuA9bJqwHAugwTMDXqQgcZNED7PIgZ5sa4o1KRATOLKKedkfayltcMJmCAA&extent=-28.872073427042995%2C26.705657147802196%2C-21.410826670490174%2C30.65888125804206&proj=16 I am assuming that the above link is giving the right image and the image from the Lunar Orbital Data Explorer is flipped. I would to like to know if this is true and if yes then why is there a flip in the image product from Lunar Orbital Data Explorer. Thank You, Shyam.