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2

If you set the project CRS in QGIS to EPSG:32718 (UTM zone 18), you get the same coordinates as reported by Google Earth. You might get different results if you have chosen another CRS. There are several CRS that are called UTM 18S (=South), but only one is based on the WGS84 ellipsoid. The negative Y coordinate looks like a UTM 18N (=North) CRS. For QGIS, ...


2

First of all, the GPS Almanac consists of information about the GPS constellation, satellites' health and their course in order to make it easier (possible) for your receiver to find them in the air. (Most of the time, you do not need to download that since you did before, but that is a discussion for another Q/A). The point is, almanac is not important for ...


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You should be able to do a simple 'select by expression' where DATECOLUMN like "% 12%" This is assuming your date is a string column. Essentially; the query is using the 'pattern' that is formed, and saying "Find me every record where there's a space, followed by 12, follow by a colon. Since your data is in 24h format, the only records criteria that ...


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Yes, they are related. One value or the other does not give you enough information for a location. You need to have both values to have a point in space.


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IMHO, you're probably overdoing it. Any GPS will collect an ok trace, and if you collect one on your phone at the same time, you have a second for reference. If you can borrow another from someone else, even better. Now load the traces over some satellite imagery (Google Earth, Mapbox or other), and you'll have plenty of confidence that your traces are ...


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I have never tried them myself, but it looks like the iScreenDisplay interface has rotation functions: iScreenDisplay Also check out screenDisplay.DisplayTransformation.Rotation() Might be a good starting point.


1

One example is if you are setting up an RTK survey, but don't have any permanent marks. In this situation, you set up a base station and observe for 6+ hours while you undertake your field work with a radio-connected rover (you might be able to do this disconnected?), then you can post-process to identify the coordinates of your base station. ...


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In my work, I combine SpatiaLite and the JTS library to display large shapefiles(SpatiaLite r-tree) and so far so good! My offline map base is OSM-Android or RMaps. Sorry for my poor English.


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The word localization is a new and, in my opinion, an annoying addition to geomatics. The question used to be: What is the difference between positioning and location? Two possible answers to which were: they're the same thing the difference depends on a specific context One context was AVL (automatic vehicle location). In the late '80s, Hassan Karimi ...


1

First, RTK stations are not always available. There are some countries where there are no or little stations, and according to this source even in the US you have states without public RTK. So you then need your own base station and if you want to make you own RTK you need an emitter in addition to the GPS receiver, so this i more expensive. EDIT: for the ...


2

A common entry-level GPS has an absolute precision of roughly 40 feets, but there are many "tricks" that help improving this precision. For instance, you can collect several points of the same position and average this position (which is not a good solution if I understand well your case) or you can use WAAS enabled GPS. I see that you live in the States, so ...


1

My favorite app for doing these kinds of things is Locus map free. It can import KML file amongst many other formats, and can work completely offline. If you need a base map, you can either download it within the app (for a fee) or add your own data either in mbtiles, or one of the other myriad formats that it supports.


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After you export your map to a tiff with world file, you can use the free program OKMap to convert it to a kmz file. You would use the Utilities-MapTiling/Garmin Custom Maps menu option. This file can then be used as a custom map in Garmin GPS units that allow custom maps, such as the 62. We do it all the time with our cruise maps.


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There is a path to making true Garmin .img maps using free tools. It's explained over at GPSFileDepot. The description is for making topos, but you can generalize the steps to make anything you want. Specifically, if you have shapefiles, you can just focus on the few steps involving shapefiles. Be warned, this process is not for the faint of heart. It relies ...


2

If all you need is combined background there is plugin for QGIS called GarminCustomMap to export map easily for Garmin devices which supports custom maps - series 62, 64 as defined here: http://www.garmin.com/us/products/onthetrail/custommaps There is also video tutorial on youtube how to use that QGIS plugin: https://www.youtube.com/watch?v=abffJeSj3zM ...


1

A zero-cost solution would be to use Openstreetmap data and the mkgmap toolchain. If your area of interest is not detailed enough, feel free to add missing features (respecting the terms of use of the data you have). For things that don't belong into Openstreetmap, I create gpx files using QGIS, and upload them with basecamp to the GPS unit. ...



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