You are right, there is more to it. The incentive from me was to not further complicate a problem that by itself can be very hard to solve. but still, a more accurate measure van only determined by including these concepts. Kind regards/met vriendelijke groet, Serge Fonville http://www.sergefonville.nl Convince Microsoft! They need to add TRUNCATE PARTITION in SQL Server https://connect.microsoft.com/SQLServer/feedback/details/417926/truncate-partition-of-partitioned-table 2013/2/28 Sean Greenslade <zootboysean@xxxxxxxxx> > > > On Thu, Feb 28, 2013 at 3:18 PM, Serge Fonville <serge.fonville@xxxxxxxxx>wrote: > >> well, not exactly. >> But I can help you (so can others) to go through code flow (it will >> probably be tedious) >> >> you have a position you start and a certain distance from that point (in a >> circle) >> From thereon you substract start(x,y) from dest(x,y) by substracting x >> from >> x and y from y the diffence is the amount of degrees between the two >> points >> are apart, if you add instead you determine a point. >> >> so for example you are currently at long: 75, lat: 31 and you want to know >> some point 6.9 miles away. >> you start by adding 0 to 75 and 0.1 to 31 you then have one point (both >> are >> degrees and one degree is roughly 69 miles) you can also do the opposite, >> add 0.1 to 75 and 0 to 31, you can also add 0.05 to both (again totaling >> 0.1), mind though the values that total 0.1 are absolute, even though the >> long/lat may be negative. >> >> The point is that the values added are combined the distance you want to >> measure against. >> From thereon you can determine if there is an address at the location >> (using reverse geo-coding). >> when increasing the number you add, you measure further and further >> you'll have to do that all arround the point you started from >> >> more information about how long/lat works: >> http://www.nationalatlas.gov/articles/mapping/a_latlong.html >> >> HTH >> >> Kind regards/met vriendelijke groet, >> >> Serge Fonville >> >> http://www.sergefonville.nl >> >> Convince Microsoft! >> They need to add TRUNCATE PARTITION in SQL Server >> >> https://connect.microsoft.com/SQLServer/feedback/details/417926/truncate-partition-of-partitioned-table >> >> <snip /> >> > > You should be careful of statements like "one degree is roughly 69 miles." > While this is true for latitude, it is only true for longitude at the > equator. To get the distance between two sets of latlon coordinates, you > need to use the great circle equation: > > http://www.movable-type.co.uk/scripts/latlong.html > > > -- > --Zootboy > > Sent from some sort of computing device. >
