Hi, I looked at the page.It looks like a neat project! Buy time you buy a case, antenna... (I don’t think they come with on), your back into the price range of a forestry grade survey GPS unit. I think the Emild single band gps (https://emlid.com/reachrs/ ) is probably a better choice unless you really want to make this a learning project. But if I understand you are really on a shoe string budget.
None of these Gps, by the way, would beat and old theodolite... if you can establish or find a good gps position (look for the city or state geomatics services) or survey point, a théodolite would give you survey grade positions. City have these points on every few blocks. You may be able to find A theodolite for free. A second hand TotalStation could be better but that will be more difficult to find in those price ranges (Shoe string). You can also rent equipment or find a college that would take this up as a teaching opportunity. Have fun! Nicolas Cadieux Ça va bien aller! > Le 23 mai 2020 à 13:52, Bernd Vogelgesang <bernd.vogelges...@gmx.de> a écrit : > > > Unfortunately, the Forest Service Website went offline (maybe this thread > caused so much traffic that it broke down? ;) ) > > I'm also desperately searching for an affordable way to have at least some > decent accuracy. I do not need submeter, but it would be fantastic if it was > possible to achieve meter accuracy. > I gave up on that Garmin stuff. They might be accurate, but I have no chance > to control this until I return home and put the recorded data on screen over > an aerial image. Those screens are a joke, and the business logic that > prevents me to put reasonable aerial imagery on the device without paying a > fortune is apita. Maybe this improved cause I last checked 5 years ago. > > Mobile phones at least in my case seem to get worse. My Motorola from 2016 > had an accuracy of less than 4 meters, most of the time less than 2. > Now I bought a Huawei 30 pro cause of the camera (my first phone with nice > pictures!), but the accuracy is a nightmare. The position is jumping around > like a dog on rabies. > I also bought a bluetooth device (Navilock BT-821G) two years ago. This is > much better than the phones GPS, tho it only receives 20 satellites maximum > (The phone claims to receive some 40). But also this device sometimes, when > walking a transect, is constantly 5 meters off the track for several several > minutes. > > As apps averaging the positions were mentioned: Does anyone have a > recommendation on such apps (for Android)? I found some, but the usability > was not that great, and some even didn't enhance anything. > > Furthermore, I stumble upon an article about a module with u-blox chip. > https://www.sparkfun.com/products/16481 > Does anyone have any experience with modules like this and what else is > needed? The description of all the stuff leaves me a bit puzzled. > > Cheers, > > Bernd > >> On 23.05.20 18:17, Michael.Dodd wrote: >> https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00118.x >> I did this quite a few years ago but in the graph in supplimentary material >> it shows how the accuracy of one consumer grade gps varies over time (at a >> fixed point). At the time I also did a lot more measurements using mobile >> phones and consumer grade units on a grid of points in the field, that was >> not published but basically the phones were often as good as if not better >> than the consumer grade gps units especially when using certain apps to >> average points. >> >> Where are my quadrats? Positional accuracy in fieldwork - Dodd - 2011 - >> Methods in Ecology and Evolution - Wiley Online Library >> Introduction. There has been much written about sampling design, spatial >> scale and the need for permanent plots in ecological long‐term monitoring, >> for example, the paper on spatial scaling in ecology has been cited over >> 1500 times, but one frequently ignored issue, intimately associated with >> sampling design, scale and permanence of plots, is how to locate positions >> accurately. >> besjournals.onlinelibrary.wiley.com >> >> From: Qgis-user <qgis-user-boun...@lists.osgeo.org> on behalf of Nicolas >> Cadieux <nicolas.cadi...@archeotec.ca> >> Sent: 23 May 2020 16:34 >> To: Randal Hale <rjh...@northrivergeographic.com> >> Cc: qgis-user@lists.osgeo.org <qgis-user@lists.osgeo.org> >> Subject: Re: [Qgis-user] wishing for accurate lattitude/longitude from a >> cell phone >> >> CAUTION: This mail comes from outside the University. Please consider this >> before opening attachments, clicking links, or acting on the content. >> >> Hi, >> >> This is a very interesting list. It basically confirms what I thought. >> Consumer Point and shoot deceives are all around 2-6m with no canopy. The >> average multiple positions basically give you a better idea as a gps may get >> lucky. It would be nice to have the full methodology for this and more data >> (like the number of satellite and the position of the constellation and the >> gps price list) but it’s very interesting none the less. I was also happy >> that the data confirms the precision of the gps Sx-Blue 11. This claims to >> be sub meter and my tests indicated that on our office unit but it’s nice to >> see it done elsewhere. For about 2000$, this gps is pretty good. As for the >> rest, the difference between 150$ and 1000$ is probably more a function of >> the options (like maps and screen size...) and not a question of precision. >> It would be nice to know what gps chips they are running... >> >> Interesting thing also is that based on my reviewing the data on my phone >> (without graph or cross tabulation tables) is that the Glonas Constellation >> does not seem to help much. Quick stats on this list would confirm this. >> Maybe this is just a figment of my imagination because there’s only so much >> information you can grad without running proper stats. >> >> Thanks for the post. >> >> Nicolas Cadieux >> Ça va bien aller! >> >> > Le 23 mai 2020 à 09:02, Randal Hale <rjh...@northrivergeographic.com> a >> > écrit : >> > >> > One other thing that may or may not be of use but the USDA Forest Service >> > Publishes a GPS Receiver Report that covers phones - and that's helped if >> > I've had a client go "Well I have a Apple <something> or a Android >> > <thing>". At least I feel slightly better going "good enough" or "no not >> > good enough". >> > >> > It should be good worldwide (but I will admit I think phones are my 'tech >> > ceiling' these days) but your mileage may vary. >> > >> > https://www.fs.fed.us/database/gps/mtdcrept/accuracy/index.htm >> > >> > Randy >> > >> >> On 5/22/20 8:55 PM, Priv.-Doz. Dr. Maria Shinoto wrote: >> >> Somehow I did not follow the discussion, but like to add some of our >> >> experience. >> >> >> >> We are doing field work in a remote region in the southern Japanese >> >> mountains, archaeological surveys on the ground based on LiDAR data. >> >> >> >> A simple Garmin etrex10 is mostly reliable in an area of 40cm by 40cm >> >> around a measured point, if used repeatedly at this point and the point >> >> is located in the middle of a valley. Even cell phones do a good enough >> >> job. As soon as we get closer to the steep slopes, the accuracy of the >> >> Garmin is less than 5 to 10 meters. We can check this with the detailed >> >> LiDAR based map, and geologists told us, that even an expensive device >> >> could not be more precise under these conditions. So we decided to >> >> measure traditionally on the ground if precise measure is necessary, >> >> otherwise note the GPS data and the location as shown in the map. >> >> >> >> To sum up, we came to the conclusion not to spend money on an expensive >> >> GPS that may not work in the shadow of steep slopes -- or in the streets >> >> of New York. -- I appreciate any additional advice, and hope that this >> >> experience can save Steve's organisation some money... >> >> >> >> Best, >> >> Maria >> >> >> >> >> >> >> >>>> Am 23.05.2020 um 03:54 schrieb Stephen Sacks <sack...@earthlink.net>: >> >>> >> >>> In order to make widely available some wise advice, I'm sending to this >> >>> list a message I received from Neil B. In addition to Neil's message >> >>> below, I want to mention that Nicolas Cadieux also provided similar >> >>> information, saying I'd have to pay around $1,000 for equipment that >> >>> gives consistently accurate location coordinates. And thanks, also to >> >>> Falk Huettmann and Bernd Vogelgesang for their replies. >> >>> >> >>> >> >>> Message from Neil B: >> >>> >> >>> Hello Stephen. >> >>> Glad that you're having su >> _______________________________________________ >> Qgis-user mailing list >> Qgis-user@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >> >> >> _______________________________________________ >> Qgis-user mailing list >> Qgis-user@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
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