During field mapping, geographic coordinates are collected using GPS, and later on these coordinates are plotted on the digital geographic map. Then, I would like to have different steps to download the GPS coordinates and plot them on a digital map. thank you
Dear Samuel Tetsopgang
These articles might be helpful, have a look:
1. https://www.floridamuseum.ufl.edu/herbarium/methods/Georeferencingbestpractices.htm
2. https://www.researchgate.net/post/How_to_find_Latitude_and_Longitude_co-ordinates_of_different_geographical_locations
3. https://pro.arcgis.com/en/pro-app/latest/help/mapping/properties/coordinate-systems-and-projections.htm
Kind Regards
Qamar Ul Islam
1. Convert GPS tracks into Shape (*.SHP) format, and open it in the GIS. That's all.
2. If number of points is very small, you can edit GIS manually.
First of all, I tend to talk a bit too much, but I hope I can help you.
Second of all, I liked Qamar's links, they are most instructive.
Third of all, you should set a couple of standards.
You see, the Earth is a giant spheroid, so, 3D. Maps (and pretty much everything we use to project stuff, even our so-called 3D softwares, as they also show their results on flat screens) are 2D, so we need ways to project a 3D world into a 2D one.
So, for starters, we need a 3D model for the Earth, or a Datum. Data are created mathematically. WGS 84 is one of many. It is satisfactory to be used internationally, but sometimes, a mathematical model can be more accurate for a specific region, such as SAD 69 (South America), Córrego Alegre (Brazilian Southeast), etc, even though its model for the rest of the world might not be so accurate (you would not want to use Córrego Alegre to base a map of, say, Oman)
Being different means that a same point on Earth will fall in different places of each model, which means it will have different coordinates for each datum. So when you say a point has the coordinates 28ºN, 40ºE, you should also state which datum you are using, because the coordinates for the same place would be different if you were using a different datum.
This is absolutely crucial. The information must be on your map. If you set your GPS system to use the same datum as your map, you should be OK. If it happens that the map uses UTM coordinates, it can be a bit annoying to work with the Deg-Min-Sec system, but at least this is easy to solve with a simple conversion. Each system is a different way of describing the same thing.
But notice that you have to set your GPS properly BEFORE going around in the field. Really.
If for any reason you are working with a GPS set to a different datum as that of your map, then you will have a bit of a headache, because now you are describing a different planet as your map.
So always set the standards first.
There are some conversion systems to fix that kind of problem if they happen to occur, but it is much easier to just work with everything set in a compatible way for starters.
Now, how you will discharge your GPS data is up to you. Most come with cables or memory cards, but you can simply also take your notebook and type everything in a spreadsheet, but depending on how many points you have gotten, this could be an absolute nightmare. Anyway, the data will be stored in a given format of your preference, or pre-set by the GPS manufacturer.
You just have to learn how the program you are using works. QGIS, for example, can import .csv spreadsheets (if you chose the type-in path), but if you happen to mistype the coordinates of a point, you can only correct it by editing the source file. It also works with other formats, and most GPS manufacturers know their format should be compatible with GIS software, so these should also be there.
You can also save your points in a .shp file, which is vectorial and can be directly edited with your software.
But notice that, when you import your points, you will probably have to confirm your projection and coordinate systems.
All the best
It would be nice to know whether you desire plotting GPS latitude and longitude as latitude and longitude or in a different format eg. UTM or local coordinates where you are and what package you intend using. Reason being GPS coordinates are spherical coordinates and you are trying to depict them on a flat or planar surface and you cannot directly do that.