Geographical data analysis
- To: mathgroup at smc.vnet.net
- Subject: [mg9565] Geographical data analysis
- From: "TAZ" <ya_right at no_spam.com>
- Date: Thu, 13 Nov 1997 01:40:27 -0500
- Organization: i2020 -- Richmond's internet partner. http://www.i2020.net
- Sender: owner-wri-mathgroup at wolfram.com
Plz send replies to gjmoyer at NOSPAM4u.net, remove nospam... All my maps are controlled by vectors with x and y coordinates (latitudes and longitudes (degrees with decimals)). The vectors shapes polygons that again constitutes geographical area types for instance municipalities or woodland or lakes or whatever. I would have thought there from universities or elsewhere might have been an enormous amount of freeware with utilities for dealing with the mathematics of geographical data but have only found an old 1973 thing. I am in desperate need for some utilities that I have no knowledge to make myself, but also other utilities might be welcome. The one I mostly need is a utility that can take two polygons decide if they overlap and give me three or more polygons that contain areas from polygon 1 area from polygon 2 and areas for both polygon 1 and 2. For instance i could have one polygon describing Lake Ontario and another describing the state Ontario. The results I need are: 1) 1 or more polygons for the part of lake Ontario that is within the state of Ontario 2) 1 or more polygons that form the part of Lake Ontario that is outside the state of Ontario(if that exists). 3) 1 or more polygons that form the part of the state of Ontario that is outside the lake of Ontario(if that exists). The next important wish is a utility that can calculate areas from the vectors. Also I need a utility that can analyse a polygon and decide if it is described clockwise or counterclockwise. Utilities that can transform from Mercator projection (which my data in reality are) to other projections as "Lambert" would also be welcome. Example of polygons: 90,67,8.406851,57.381565 8.603993,57.355554 8.623441,57.350039 8.637969,57.349599 8.645163,57.347066 8.64548,57.340508 8.654961,57.337411 8.655435,57.328042 8.648237,57.325048 8.644299,57.314838 8.646252,57.309215 8.655546,57.296375 8.654706,57.282229 8.641305,57.274834 8.638686,57.269214 8.637862,57.262656 8.628066,57.260129 8.623002,57.254884 8.623,57.251511 8.609941,57.243925 8.614995,57.235492 8.621192,57.232586 8.617921,57.218346 8.594279,57.204482 8.579126,57.191832 8.565764,57.191829 8.536095,57.199032 8.511332,57.201025 8.510999,57.201051 8.510256,57.201184 8.466794,57.20891 8.456684,57.209555 8.42077,57.219909 8.414718,57.224023 8.400671,57.228311 8.373364,57.240165 8.33807,57.247967 8.326815,57.247006 8.294416,57.258456 8.276465,57.257661 8.240441,57.270026 8.231858,57.276629 8.222842,57.283562 8.202207,57.288839 8.195778,57.294629 8.191674,57.29649 8.189065,57.295919 8.184774,57.300122 8.181634,57.303579 8.186463,57.310905 8.191366,57.311015 8.197966,57.321532 8.195942,57.327805 8.204486,57.340671 8.203271,57.346161 8.200381,57.359213 8.201474,57.381708 8.196637,57.390783 8.197666,57.402875 8.207576,57.429333 8.221999,57.448212 8.23218,57.457006 8.2404,57.464102 8.249946,57.480527 8.253857,57.484192 8.249684,57.492428 8.249815,57.496551 8.268962,57.505316 8.275379,57.50402 8.277397,57.497746 8.291554,57.493188 8.294536,57.489447 8.299475,57.487678 8.304424,57.484222 8.320982,57.462518 8.333654,57.45636 8.348271,57.453577 8.40202,57.429773 8.424824,57.425494 8.439114,57.417547 8.44551,57.416149 8.451899,57.416812 8.465979,57.421885 8.476807,57.41796 8.489466,57.400824 8.525696,57.381357 8.542728,57.377617 8.561725,57.366285 8.570072,57.365162 8.603993,57.355554 END 90,66,8.687958,57.525571 8.68832,57.524023 8.684382,57.525339 8.683412,57.529556 8.687023,57.528615 8.688834,57.529456 8.693764,57.529543 8.693087,57.524485 8.68832,57.524023 END