Hi Vissarion,
2017-03-20 20:29 GMT+08:00 Vissarion Fisikopoulos <[hidden email]>: > Hi Ruoyun, > > > - The main work I should do during GSoC about project 1 is just to > improve > > the algorithms of compare two distances of two point pairs or try to > > consider different situations which used compare distance predicates to > > avoid calculation? > > the project is about algorithms that does not compute the actual distance > but an approximation (as rough as possible) that suffices to accurately > compare the lengths of two geodesic segments on the ellipsoid > > continue to write my proposal. > > - Do "In some algorithms there is the need to compare two distances of > two > > point pairs" this means compare two points distances on Earth? Or on > every > > ellipsoid model? > > the later (see answer above) > > > - Do I need to find the approaches of filter by myself? Could you please > > help me get more information about these? Like the implement detail about > > the predicate compare_distance function, mathematical calculation papers > > about compare distance on ellipsoid? > > Well we give one approach on the website (there is another proposal of > another > candidate on the list). My opinion is that if you understand these > approaches > (pos and cons, differences etc) that will help you towards a solid > application. > Having another idea for an approach will definitely strengthen you > application. > Thanks for your help. I can get the point of those approaches and will try to have new ideas. :) > > - In my view, just like compute the shortest distance between two given > > points on Earth, the background approach can be used. And I used > cartisian > > coordinate to avoid many trigonometric function calculation, but I can > not > > find more improve with my lacking knowledge, could you give me some > aspects > > to get more approaches? > > Please see answer above > > At this point I think it is better to jump to boost list because our > discussion > could interest more people. I will not copy anything of our private > conversation > there but feel free to do the jump and I will continue answering there. > > Btw, any news from you test and comparison with Boost.Geometry. > > I reply you and jump to boost with your advice. Hope this will help more Vissarion > > ps. you can send questions whenever you want, I will answer them a.s.a.p. > my zone is UTC+2 > > Thanks for your answer. Best regards. Ruoyun -- Northwest University of China Software Engineering [hidden email] <[hidden email]> _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost |
Hi Adam and Vissarion,
During these days I discussed the ideas of project 1 and begin to write my proposal. Here are what I learn about these project. 1.For the approach of compute the 3D cartesian distances first and if these numbers are not "far enough" then fall back to expensive geographic distance calculation otherwise return the result by comparing those numbers obtained by less expensive cartesian compuation. The main problems is declare the "far enough". To figure out this problem, I would implement the method, test the result between function compare_distance and this method, then adjust parameter to limit deviation in an acceptable range(maybe it would be 1e-6 correapongs, the accurate value should be discussed by specific condition) 2.For the approach of perform a local spheroid approximation and return the 2D distance. The main problem is to test the acceptable range of using spheroid approximation. The solution is same as answer above. 3.For the approach of getting 2 intersections of plane (which would be ellipse) with the help given points and compute the respective distances using those ellipses. In my understand of these approach, it means we need to get cross-section through the center of ellipsoid and the geodesic segments. But I am not sure that the geodesic segments of two points whether can get a cross-section through the center of ellipsoid, and whether the cross-section is ellipse that we can calculate the sectorial area easy to compare. After check out the geodesic knowledge from differential geometry for a long time. I got some prove, but I think it isn't very reliable. 4.I have an reliable approach is that we could use the algorithms in "map projection" just like Lambert Conformal Conic, Gauss–Krüger projection, Mercator projection...etc, Those projections make the point on 3D to 2D with reliable functions, although most of these projections use longitude and latitude, we could transform our cartisian coordinate into Spherical coordinate then transform them into longitude and latitude then use the projection to approximately calculate. All of above is what I discussed during these days, Could you please provide me some advise about them so I can strenthen my proposal?And if there has any problems about my poor English description please tell me, I will try my best to explain more clearly:) Thanks all for your reading! Looking forward from you.:) Ruoyun -- Northwest University of China Software Engineering [hidden email] <[hidden email]> _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost |
Hi Adam and Vissarion,
2017-03-25 0:46 GMT+08:00 Ruoyun Jing <[hidden email]>: > Hi Adam and Vissarion, > > During these days I discussed the ideas of project 1 and begin to write my > proposal. Here are what I learn about these project. > > 1.For the approach of compute the 3D cartesian distances first and if > these numbers are not "far enough" then fall back to expensive geographic > distance calculation otherwise return the result by comparing those numbers > obtained by less expensive cartesian compuation. > > The main problems is declare the "far enough". To figure out this problem, > I would implement the method, test the result between function > compare_distance and this method, then adjust parameter to limit deviation > in an acceptable range(maybe it would be 1e-6 correapongs, the accurate > value should be discussed by specific condition) > > > 2.For the approach of perform a local spheroid approximation and return > the 2D distance. > > The main problem is to test the acceptable range of using spheroid > approximation. The solution is same as answer above. > > > 3.For the approach of getting 2 intersections of plane (which would be > ellipse) with the help given points and compute the respective distances > using those ellipses. > > In my understand of these approach, it means we need to get cross-section > through the center of ellipsoid and the geodesic segments. But I am not > sure that the geodesic segments of two points whether can get a > cross-section through the center of ellipsoid, and whether the > cross-section is ellipse that we can calculate the sectorial area easy to > compare. After check out the geodesic knowledge from differential geometry > for a long time. I got some prove, but I think it isn't very reliable. > > > 4.I have an reliable approach is that we could use the algorithms in "map > projection" just like Lambert Conformal Conic, Gauss–Krüger projection, > Mercator projection...etc, > > Those projections make the point on 3D to 2D with reliable functions, > although most of these projections use longitude and latitude, we could > transform our cartisian coordinate into Spherical coordinate then > transform them into longitude and latitude then use the projection to > approximately calculate. > > I read more about projection and we could use Local Cartesian Projection, model. > > All of above is what I discussed during these days, Could you please > provide me some advise about them so I can strenthen my proposal?And if > there has any problems about my poor English description please tell me, I > will try my best to explain more clearly:) > > Thanks all for your reading! > > Looking forward from you.:) > > Ruoyun > -- > Northwest University of China > Software Engineering > [hidden email] <[hidden email]> > -- Northwest University of China Software Engineering [hidden email] <[hidden email]> _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost |
Hi Ruoyun,
it seems that you are making a big effort understanding the tools of the area. Your ideas are more than enough to form a proposal. you should concentrate to make them more clear. Try to keep it simple and clear. Also regarding you English, I am not a native speaker to give professional advice, but also here try to make short sentences with simple English, in some parts it is not very easy to understand what you want to say, but in general I think you are passing the message. Looking forward to see your draft proposal. Best, Vissarion. On 27 March 2017 at 14:39, Ruoyun Jing <[hidden email]> wrote: > Hi Adam and Vissarion, > > 2017-03-25 0:46 GMT+08:00 Ruoyun Jing <[hidden email]>: >> >> Hi Adam and Vissarion, >> >> During these days I discussed the ideas of project 1 and begin to write my >> proposal. Here are what I learn about these project. >> >> 1.For the approach of compute the 3D cartesian distances first and if >> these numbers are not "far enough" then fall back to expensive geographic >> distance calculation otherwise return the result by comparing those numbers >> obtained by less expensive cartesian compuation. >> >> The main problems is declare the "far enough". To figure out this problem, >> I would implement the method, test the result between function >> compare_distance and this method, then adjust parameter to limit deviation >> in an acceptable range(maybe it would be 1e-6 correapongs, the accurate >> value should be discussed by specific condition) >> >> >> 2.For the approach of perform a local spheroid approximation and return >> the 2D distance. >> >> The main problem is to test the acceptable range of using spheroid >> approximation. The solution is same as answer above. >> >> >> 3.For the approach of getting 2 intersections of plane (which would be >> ellipse) with the help given points and compute the respective distances >> using those ellipses. >> >> In my understand of these approach, it means we need to get cross-section >> through the center of ellipsoid and the geodesic segments. But I am not sure >> that the geodesic segments of two points whether can get a cross-section >> through the center of ellipsoid, and whether the cross-section is ellipse >> that we can calculate the sectorial area easy to compare. After check out >> the geodesic knowledge from differential geometry for a long time. I got >> some prove, but I think it isn't very reliable. >> >> >> 4.I have an reliable approach is that we could use the algorithms in "map >> projection" just like Lambert Conformal Conic, Gauss–Krüger projection, >> Mercator projection...etc, >> >> Those projections make the point on 3D to 2D with reliable functions, >> although most of these projections use longitude and latitude, we could >> transform our cartisian coordinate into Spherical coordinate then transform >> them into longitude and latitude then use the projection to approximately >> calculate. >> > I read more about projection and we could use Local Cartesian Projection, > one of the equidistant projection, which can provide ellipse and spheroid > model. > >> >> >> All of above is what I discussed during these days, Could you please >> provide me some advise about them so I can strenthen my proposal?And if >> there has any problems about my poor English description please tell me, I >> will try my best to explain more clearly:) >> >> Thanks all for your reading! >> >> Looking forward from you.:) >> >> Ruoyun >> -- >> Northwest University of China >> Software Engineering >> [hidden email] > > > > > -- > Northwest University of China > Software Engineering > [hidden email] _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost |
Hi Vissarion,
Here is my [proposal]( https://docs.google.com/document/d/1wj9xPSmdehh9MzE-3MGHMu7cwMhDPASUEvU9pJbrW7k/edit?usp=sharing),but it do not complete yet, now you can comment it and I would like to receive your advice.:) Also I am adding to the boost mailing list, it is my pleasure to get comment from you. I will finished the proposal in recent days, once I finished it I will push the draft on GSoC page. Thanks all for your help! Ruoyun. 2017-03-28 18:42 GMT+08:00 Vissarion Fisikopoulos <[hidden email]>: > Hi Ruoyun, > > it seems that you are making a big effort understanding the tools of > the area. Your ideas are more than > enough to form a proposal. you should concentrate to make them more > clear. Try to keep it simple and > clear. Also regarding you English, I am not a native speaker to give > professional advice, but also here > try to make short sentences with simple English, in some parts it is > not very easy to understand what > you want to say, but in general I think you are passing the message. > > Looking forward to see your draft proposal. > > Best, > Vissarion. > > On 27 March 2017 at 14:39, Ruoyun Jing <[hidden email]> wrote: > > Hi Adam and Vissarion, > > > > 2017-03-25 0:46 GMT+08:00 Ruoyun Jing <[hidden email]>: > >> > >> Hi Adam and Vissarion, > >> > >> During these days I discussed the ideas of project 1 and begin to write > my > >> proposal. Here are what I learn about these project. > >> > >> 1.For the approach of compute the 3D cartesian distances first and if > >> these numbers are not "far enough" then fall back to expensive > geographic > >> distance calculation otherwise return the result by comparing those > numbers > >> obtained by less expensive cartesian compuation. > >> > >> The main problems is declare the "far enough". To figure out this > problem, > >> I would implement the method, test the result between function > >> compare_distance and this method, then adjust parameter to limit > deviation > >> in an acceptable range(maybe it would be 1e-6 correapongs, the accurate > >> value should be discussed by specific condition) > >> > >> > >> 2.For the approach of perform a local spheroid approximation and return > >> the 2D distance. > >> > >> The main problem is to test the acceptable range of using spheroid > >> approximation. The solution is same as answer above. > >> > >> > >> 3.For the approach of getting 2 intersections of plane (which would be > >> ellipse) with the help given points and compute the respective distances > >> using those ellipses. > >> > >> In my understand of these approach, it means we need to get > cross-section > >> through the center of ellipsoid and the geodesic segments. But I am not > sure > >> that the geodesic segments of two points whether can get a cross-section > >> through the center of ellipsoid, and whether the cross-section is > ellipse > >> that we can calculate the sectorial area easy to compare. After check > out > >> the geodesic knowledge from differential geometry for a long time. I got > >> some prove, but I think it isn't very reliable. > >> > >> > >> 4.I have an reliable approach is that we could use the algorithms in > "map > >> projection" just like Lambert Conformal Conic, Gauss–Krüger projection, > >> Mercator projection...etc, > >> > >> Those projections make the point on 3D to 2D with reliable functions, > >> although most of these projections use longitude and latitude, we could > >> transform our cartisian coordinate into Spherical coordinate then > transform > >> them into longitude and latitude then use the projection to > approximately > >> calculate. > >> > > I read more about projection and we could use Local Cartesian Projection, > > one of the equidistant projection, which can provide ellipse and > spheroid > > model. > > > >> > >> > >> All of above is what I discussed during these days, Could you please > >> provide me some advise about them so I can strenthen my proposal?And if > >> there has any problems about my poor English description please tell > me, I > >> will try my best to explain more clearly:) > >> > >> Thanks all for your reading! > >> > >> Looking forward from you.:) > >> > >> Ruoyun > >> -- > >> Northwest University of China > >> Software Engineering > >> [hidden email] > > > > > > > > > > -- > > Northwest University of China > > Software Engineering > > [hidden email] > -- Northwest University of China Software Engineering [hidden email] <[hidden email]> _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost |
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