+hydrodis Posted June 20, 2016 Share Posted June 20, 2016 Is there a app which can be downloaded to a desktop computer that will allow you to average waypoint co-ords when entering them manually. Needed to help solve a puzzle. Quote Link to comment
+MartyBartfast Posted June 20, 2016 Share Posted June 20, 2016 If the degrees part of the co-ords are the same, and it's just the minutes parts that are different then stick just the minutes part into your favourite spreadsheet and average them out. E.G N50 51.123, W001 01.456 & N 50 52.014, W001 00.983 just calculate (51.123+52.014)/2 and (01.456+00.983)/2 and when you have the average values put the N50 and W001 parts back. Quote Link to comment
+hydrodis Posted June 20, 2016 Author Share Posted June 20, 2016 I know how do do that but when you have a lot to do software would soon breeze through it. Quote Link to comment
+MartyBartfast Posted June 20, 2016 Share Posted June 20, 2016 I know how do do that but when you have a lot to do software would soon breeze through it. That's why I suggested doing it in a spreadsheet. In excel if you have a list of co-ords in a text file, you could open it as a delimited text file, choosing space and comma as the delimiters, which will break up each part of the co-ords into different columns, then use the "average" function to do the maths, e.g. if you enter into a cell "=average(a1:a23)" (without the quote marks) it will work out the average of all the values in the first 23 cells of column A. Quote Link to comment
+hydrodis Posted June 20, 2016 Author Share Posted June 20, 2016 I don't have excel,only open office don't think it has the same options. Quote Link to comment
+MartyBartfast Posted June 20, 2016 Share Posted June 20, 2016 I don't have excel,only open office don't think it has the same options. I use OpenOffice too (at home), but just made the assumption about excel as that seems to be what everyone else uses. google says OpenOffice Calc has the Average function too, but I can't check it from work. Another way you could work out the average is to do "=sum(A1:A23)/23" and I know Calc does have the sum function, but that requires changing the formula based on how many rows you're averaging) Quote Link to comment
+Viajero Perdido Posted June 20, 2016 Share Posted June 20, 2016 OpenOffice is packed with features. Of course it does averaging. That's a basic one. @AVERAGE Why assume that, just because it's free, it's no good? Quote Link to comment
+Mineral2 Posted June 25, 2016 Share Posted June 25, 2016 (edited) Oy.... OpenOffice LibreOffice Apple Numbers Google Docs They're all compatible with Microsoft Excel. Same formula syntax, same formulas. Sometimes there are multiple formula options for the same operation to be backward compatible with older versions of each of the other software packages. The centroid of a cluster of points in n dimensions is the vector of the means of each of the n dimensions. In two dimensional space, the center of a cluster of points with coordinates (x_i, y_i) is (mean(x), mean(y)). Personally, I do all of my calculations in R. Edited June 25, 2016 by mineral2 Quote Link to comment
+Team CowboyPapa Posted June 28, 2016 Share Posted June 28, 2016 Roger that regarding Excel and LibreOffice compatibility. My desktop OS is W7 which hosts MS Office 2003, while my laptop's W10 does not. Consequently, I store all my Excel and Word files in Dropbox. Then when working from my desktop, I am using MS Excel and MS; from laptop, working same files with LibreOffice. Quote Link to comment
+Team CowboyPapa Posted June 30, 2016 Share Posted June 30, 2016 The coordinate averaging subject reminds me of the previously discussed question of what is the basis of a GPSr's EPE value. All units display a value for each location; however, AFAIK, there has not been a provision of a unit's statistical definition of EPE value. For example, how may readings at that location would be within the displayed EPE? 50%? One standard deviation? Etc.? OTOH, a user can determine that relationship by coordinate averaging. Quote Link to comment
+The A-Team Posted June 30, 2016 Share Posted June 30, 2016 The coordinate averaging subject reminds me of the previously discussed question of what is the basis of a GPSr's EPE value. All units display a value for each location; however, AFAIK, there has not been a provision of a unit's statistical definition of EPE value. For example, how may readings at that location would be within the displayed EPE? 50%? One standard deviation? Etc.? The answer varies slightly between manufacturers and their specific proprietary formulas, but generally the displayed EPE ("Estimated Position Error") on a device means that 50% of position readings are statistically likely to fall within that range. Note that this also means that 50% of readings could be outside of that range. If you double the EPE figure, it indicates that 95% of readings will fall within that doubled range. If you want to spend a few hours reading some dry statistical discussion, there's lots of information available if you Google "estimated position error". Quote Link to comment
ohgood Posted June 30, 2016 Share Posted June 30, 2016 The coordinate averaging subject reminds me of the previously discussed question of what is the basis of a GPSr's EPE value. All units display a value for each location; however, AFAIK, there has not been a provision of a unit's statistical definition of EPE value. For example, how may readings at that location would be within the displayed EPE? 50%? One standard deviation? Etc.? The answer varies slightly between manufacturers and their specific proprietary formulas, but generally the displayed EPE ("Estimated Position Error") on a device means that 50% of position readings are statistically likely to fall within that range. Note that this also means that 50% of readings could be outside of that range. If you double the EPE figure, it indicates that 95% of readings will fall within that doubled range. If you want to spend a few hours reading some dry statistical discussion, there's lots of information available if you Google "estimated position error". I've tested by revisiting dropped waypoints, both with and without averaging. of course averaging is closer, but without us plenty good enough, unless is some land formation that produces bounces. honestly these things are pretty good. Quote Link to comment
+ecanderson Posted July 1, 2016 Share Posted July 1, 2016 Which simply says that if closer is better, averaging is preferred. As for EPE (The-A-Team), we've seen some simply absurd EPE figures being provided by certain cell phone apps (1 foot or less), so I don't put much stock in any reading where the use of 'within x feet y % of the time' isn't provided as a hard spec. The use of 50% is the normal 'CEP' description for EPE. At one time, it seemed that this was the measurement Garmin was displaying, but I haven't tried to pin it down on anything they've made recently. Personal experience says that it may currently be a bit better than 50%. Quote Link to comment
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