Re: [R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
On 27 Mar 2015 23:50, Robert J. Hijmans r.hijm...@gmail.com wrote: Are these really reasonable reasons? I do not think so, given that the question had nothing to do with map navigation and the person asking appears to live in the UK. ??? How did you figure that out? He gave some phone numbers that had Botswana country codes and a southern hemisphere utm zone code! Elementary my dear Robert! But yes, as I said, if there's a local standard use it. To find the local standard, buy a paper map and read the projection info! I would never use UTM in the uk when epsg:27700 is our standard. Moreover, other projections have, or can have, their units in meters as well (or feet or miles or whatever you might fancy). UTM indeed appears to be an unfortunate default that deserves some pushback. I see utm as a last resort rather than a default. However finding a better coordinate system in the maze of epsg codes can lead to people using the wrong thing, and unless you span several zones, utm is never that wrong... Robert On Fri, Mar 27, 2015 at 2:28 PM, Michael Sumner mdsum...@gmail.com wrote: They are reasonable reasons, but traversing zones is a pain, you should see if using one or the other is sufficient. I would check carefully the distances you get against ellipsoidal calculations. Cheers, Mike On Sat, 28 Mar 2015 07:30 Andrew Duff andrewad...@gmail.com wrote: A number of field folks prefer UTM because -it matches legacy paper USGS quad map series traditionally used for field navigation -units are in meters and can be used to gauge field distances from a coordinate readout On Mar 27, 2015, at 10:48 AM, Michael Sumner mdsum...@gmail.com wrote: There is no good natural reason to use UTM, it mistifies me why our community tolerates this bizarre default. I always use a local equal-area projection unless some other compromise dictates a different choice. Cheers, Mike On Fri, 27 Mar 2015 21:28 Barry Rowlingson b.rowling...@lancaster.ac.uk wrote: If you have lat-long data that crosses two UTM zones then its generally okay to just pick *one* and transform all the points to that. Use the one that has the most points in. Basically use the UTM zones as guidelines to pick one UTM zone coordinate system. Unless your data spans several zones and you want quite high accuracy of distance measurements. Some points bleeding over into an adjacent zone are no problem. All projections are approximations to the earth's spheroid, so points that are within a single UTM zone have some distortion in their distance or angle relationships. Transforming points that are within an adjacent UTM zone is just an extension of that distortion. You can compute the precise distance error if you want for the furthest points by comparing with the geodesic distance. Alternatively you might find there is a coordinate system that spans your dataset nicely - often when a country or an island or a region crosses UTM zones there is an official coordinate system defined that is used by the authorities there. Also alternatively, there's nothing to stop you defining a transverse mercator system based on the centre of your data. Barry On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso selebat...@yahoo.co.uk wrote: Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Re: [R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
If you have lat-long data that crosses two UTM zones then its generally okay to just pick *one* and transform all the points to that. Use the one that has the most points in. Basically use the UTM zones as guidelines to pick one UTM zone coordinate system. Unless your data spans several zones and you want quite high accuracy of distance measurements. Some points bleeding over into an adjacent zone are no problem. All projections are approximations to the earth's spheroid, so points that are within a single UTM zone have some distortion in their distance or angle relationships. Transforming points that are within an adjacent UTM zone is just an extension of that distortion. You can compute the precise distance error if you want for the furthest points by comparing with the geodesic distance. Alternatively you might find there is a coordinate system that spans your dataset nicely - often when a country or an island or a region crosses UTM zones there is an official coordinate system defined that is used by the authorities there. Also alternatively, there's nothing to stop you defining a transverse mercator system based on the centre of your data. Barry On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso selebat...@yahoo.co.uk wrote: Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
[R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Re: [R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
A number of field folks prefer UTM because -it matches legacy paper USGS quad map series traditionally used for field navigation -units are in meters and can be used to gauge field distances from a coordinate readout On Mar 27, 2015, at 10:48 AM, Michael Sumner mdsum...@gmail.com wrote: There is no good natural reason to use UTM, it mistifies me why our community tolerates this bizarre default. I always use a local equal-area projection unless some other compromise dictates a different choice. Cheers, Mike On Fri, 27 Mar 2015 21:28 Barry Rowlingson b.rowling...@lancaster.ac.uk wrote: If you have lat-long data that crosses two UTM zones then its generally okay to just pick *one* and transform all the points to that. Use the one that has the most points in. Basically use the UTM zones as guidelines to pick one UTM zone coordinate system. Unless your data spans several zones and you want quite high accuracy of distance measurements. Some points bleeding over into an adjacent zone are no problem. All projections are approximations to the earth's spheroid, so points that are within a single UTM zone have some distortion in their distance or angle relationships. Transforming points that are within an adjacent UTM zone is just an extension of that distortion. You can compute the precise distance error if you want for the furthest points by comparing with the geodesic distance. Alternatively you might find there is a coordinate system that spans your dataset nicely - often when a country or an island or a region crosses UTM zones there is an official coordinate system defined that is used by the authorities there. Also alternatively, there's nothing to stop you defining a transverse mercator system based on the centre of your data. Barry On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso selebat...@yahoo.co.uk wrote: Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Re: [R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
They are reasonable reasons, but traversing zones is a pain, you should see if using one or the other is sufficient. I would check carefully the distances you get against ellipsoidal calculations. Cheers, Mike On Sat, 28 Mar 2015 07:30 Andrew Duff andrewad...@gmail.com wrote: A number of field folks prefer UTM because -it matches legacy paper USGS quad map series traditionally used for field navigation -units are in meters and can be used to gauge field distances from a coordinate readout On Mar 27, 2015, at 10:48 AM, Michael Sumner mdsum...@gmail.com wrote: There is no good natural reason to use UTM, it mistifies me why our community tolerates this bizarre default. I always use a local equal-area projection unless some other compromise dictates a different choice. Cheers, Mike On Fri, 27 Mar 2015 21:28 Barry Rowlingson b.rowling...@lancaster.ac.uk wrote: If you have lat-long data that crosses two UTM zones then its generally okay to just pick *one* and transform all the points to that. Use the one that has the most points in. Basically use the UTM zones as guidelines to pick one UTM zone coordinate system. Unless your data spans several zones and you want quite high accuracy of distance measurements. Some points bleeding over into an adjacent zone are no problem. All projections are approximations to the earth's spheroid, so points that are within a single UTM zone have some distortion in their distance or angle relationships. Transforming points that are within an adjacent UTM zone is just an extension of that distortion. You can compute the precise distance error if you want for the furthest points by comparing with the geodesic distance. Alternatively you might find there is a coordinate system that spans your dataset nicely - often when a country or an island or a region crosses UTM zones there is an official coordinate system defined that is used by the authorities there. Also alternatively, there's nothing to stop you defining a transverse mercator system based on the centre of your data. Barry On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso selebat...@yahoo.co.uk wrote: Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Re: [R-sig-Geo] Help with latlong to UTM conversion when UTM zones are different
Are these really reasonable reasons? I do not think so, given that the question had nothing to do with map navigation and the person asking appears to live in the UK. Moreover, other projections have, or can have, their units in meters as well (or feet or miles or whatever you might fancy). UTM indeed appears to be an unfortunate default that deserves some pushback. Robert On Fri, Mar 27, 2015 at 2:28 PM, Michael Sumner mdsum...@gmail.com wrote: They are reasonable reasons, but traversing zones is a pain, you should see if using one or the other is sufficient. I would check carefully the distances you get against ellipsoidal calculations. Cheers, Mike On Sat, 28 Mar 2015 07:30 Andrew Duff andrewad...@gmail.com wrote: A number of field folks prefer UTM because -it matches legacy paper USGS quad map series traditionally used for field navigation -units are in meters and can be used to gauge field distances from a coordinate readout On Mar 27, 2015, at 10:48 AM, Michael Sumner mdsum...@gmail.com wrote: There is no good natural reason to use UTM, it mistifies me why our community tolerates this bizarre default. I always use a local equal-area projection unless some other compromise dictates a different choice. Cheers, Mike On Fri, 27 Mar 2015 21:28 Barry Rowlingson b.rowling...@lancaster.ac.uk wrote: If you have lat-long data that crosses two UTM zones then its generally okay to just pick *one* and transform all the points to that. Use the one that has the most points in. Basically use the UTM zones as guidelines to pick one UTM zone coordinate system. Unless your data spans several zones and you want quite high accuracy of distance measurements. Some points bleeding over into an adjacent zone are no problem. All projections are approximations to the earth's spheroid, so points that are within a single UTM zone have some distortion in their distance or angle relationships. Transforming points that are within an adjacent UTM zone is just an extension of that distortion. You can compute the precise distance error if you want for the furthest points by comparing with the geodesic distance. Alternatively you might find there is a coordinate system that spans your dataset nicely - often when a country or an island or a region crosses UTM zones there is an official coordinate system defined that is used by the authorities there. Also alternatively, there's nothing to stop you defining a transverse mercator system based on the centre of your data. Barry On Fri, Mar 27, 2015 at 7:44 AM, moses selebatso selebat...@yahoo.co.uk wrote: Hello I have animal movement data that I have converted from Lat/Long to UTM, unfortunately the data falls in two UTM zones (34S and 35S). For some reason R cannot display both of them in the same window (the 35S data is way off the expected location). The question is how do I convert the data such that R can correctly read it? Moses SELEBATSO (+267) 318 5219 (H) (+267) 716 393 70 (C) (+267) 738 393 70 (C [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
