Questions tagged [gps]

This tag refers generically to *any* space-based satellite navigation system that provides location and time information.

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Why do we see grid pattern in mobility data

We have been analysing GPS data for one of our clients. But, I've been stumbling up a grid pattern issue and i couldn't find any explanation apart from insertion of synthetic data. Has anyone else ...
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QGIS Saving GPS Track

I am using QGIS v3.24.3-Tisler and have connected an external USB GPS unit (G-START IV) to my laptop. Through the GPS Panel I am able to connect to the GPS fine and the track log is visible and ...
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Attributes for points created by Intersect tool

Scenario: I am using ArcMap 10.3.1 to find the locations where an animal crosses a road from GPS data and the associated attributes such as X and Y (which I can calculate) and the date and time of ...
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Adding in points based on description no GPS data using ArcGIS Pro

I am working on a project that has a mix of points where half have specific GPS data and the other half only have descriptions of where the points are. I have added in and moved the GPS points to the ...
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Apparent movement in stationary GPS

I have a U-blox M9N GPS module and I wrote a simple script to acquire raw data. I acquired some data while the module was stationary and I plotted the received coordinates. As you can see in the image ...
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QField GPS position

I would like to put a .png image on QField and navigate with the GPS over it, on an Android smartphone. I managed to do this in an older version, but now the GPS does not move in the image, anyone ...
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Trilateration using latitude/longitude points, and distances

I want to find out an unknown target location (latitude and longitude co-ordinates). There are +3 lat-long known points and for each point a distance in meters to the target location. I found some ...
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Sudden change in altitude during measurement with GNSS

We work For some time now we have been working with QField and the GNSS receiver from Emlid. We get the accuracy via bluethoot from the receiver to QField. Lately, however, the measurements have been ...
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Calculating coordinates of two GPS points whose line through them is perpendicular to two other GPS points

Given two GPS points A and B, I would like to compute the GPS coordinates A1 and A2. [A1A2] forms a segment perpendicular to segment [AB]. For this, I start to compute M1, which is the midpoint ...
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Confusing GPS coordinates [duplicate]

I'm reposting this question for the sake of clarity. I've been given a spreadsheet with coordinates that are in a variety of formats, all to be converted to DD for standardisation. I'm confused about ...
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Creating buffers in ArcGIS Pro from points with variable accuracies

I have quadrilateral forest sample plots defined by GPS coordinates (and accompanying accuracies) taken at each plot corner. Using ArcGIS Pro, I inputted these coordinates as points and created ...
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QField GPS error while tracking lines

I have been using QField for a while now testing whether our team should switch over to it for data collection. All was going well then we started getting really bad GPS errors while collecting lines. ...
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How to achieve a cm accuracy in GNSS?

I am currently working on a project about the GNSS precise positioning, I want to know which modules or materials needed in order to get an accuracy of few centimeters.
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Wrong UTM zone settings in GPS receiver

I recently made a survey with an rtk GPS in an area within the UTM zone 32 N. Alas, the instrument was set to work on zone 33 N. When I load the points on a map applying the zone 32 projection (EPSG ...
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Does GPS receiver use spheres or hyperboloids to solver for position?

I've found in many articles that GPS devices use the spheres theory to get the its position, but sometimes I read that these devices solve for time differences between satellites transmissions, using ...
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Interpreting Camera GPSYaw to Geographic Direction

If the GIS SE is not the place for this question, please point me in the right direction. I have been extracting the geographic information from a number of photographs. This spatial information is ...
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In some NMEA GPGGA frame, what is the UTC timestamp?

In some NMEA GPGGA frame, there is an UTC Timestamp. What timestamp is this? It could be: The NMEA frame reception timestamp Some satellite transmission timestamp The NMEA frame start of build ...
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Advise on GPS logging for walking trails [closed]

Context: I am part of a volunteer organisation that needs to accurately log the GPS coordinates of walking trails. They cover around 350km. They are marked with waymarkers and signs, which we also ...
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Field Equipment: Avenza Pro reports iPad internal GPS accuracy when paired with EOS Arrow 100 GNSS Receiver

I would like your input on an issue I'm having with Avenza Pro on an iPad mini 6, paired with an EOS Arrow 100 GNSS receiver. The Arrow pairs with the iPad and reports submeter hrms inside the Eos ...
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Can PPK (NOT RTK) be done with any mapping drone?

If PPK is by definition post processed and does not require a live connection to the base-station, why wouldn’t be possible to use any drone and post process the resulting coordinate data (assuming ...
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How to add GPS points from a CSV/Excel file to a QGIS project? [duplicate]

I thought I knew QGIS quite a bit by now, but a straight forward simple task recently brought me close to frustration. I had collected the GPS coordinates of points using my cellphone in an Excel ...
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Gaps and Islands problem in PostGIS for GPS traces

I'm using ST_MakeLine to create traces of ship movements. The query below yields all the GPS points on a certain day, and I'm using ST_Within to only find ships in the navigable portions of the river. ...
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Minimum number of satellites per constellation in Multi-constellation Navigation

Relating to my previous question, I'm trying to understand how the LS method work for multi-constellation GNSS trilateration/multilateration. I understand for 2 constellations, trilateration require ...
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Updating first occurence of duplicate with lowest value in given field using ArcPy cursor

I have a few hundred GPS data points (saved in an ArcGIS Pro 2.9 file geodatabase) that logged simultaneously with different speeds. I am looking to write a Python script that will compare each row's ...
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Multi-Constellation GNSS Trilateration Code Error

I’m trying to implement a multi-constellation trilateration code in Python to test an anti-spoofing mechanism. With reference of a single trilateration from this Github page, I attempted to execute a ...
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Diagonal distance of two aircraft

I want to calculate the diagonal distance of two moving aircraft to estimate relative velocity. Since the altitude and GPS position(longitude, latitude in decimal degrees WGS-84) of those two are ...
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Latitude, longitude, elevation and altitude of satellites on a specific GPS receiver

I am currently working on calculating the GPS receiver's latitude and longitude coordinates by using three satellites above the earth. I have used the website https://www.n2yo.com/ to get information ...
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Terrasync detects positions incompatible with current coordinate system. Data was transferred from KML

Basically, I need to get a simple parcel boundary onto a handheld Trimble GPS with TerraSync software. I'll attempt to outline my workflow thus far. Georeferenced image from parcel map in ArcMap and ...
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Recording Internal GPS coordinates in Terrasync

I work in the exploration department of a mining company. We use a Trimble receiver to record the locations of our drill holes. We also use the Trimble handheld to record the handheld's internal GPS ...
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Improve ALOS World 3D vertical precision with GPS data from fieldwork

I'm working on sport topo maps in Russia, european part (Pskov region, near Estonia/Latvia border), typical map is from 1 to 10 km2 in size. The most precise source of DEM for generating relief lines ...
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Activating the GPS on QField for Windows Desktop (beta)

Has anyone figured out how to activate the GPS on the computer to use in QField-Windows? I have a Getac field tablet/computer. I've created a QGIS Project with 3 vector layers and packaged for QField. ...
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Connect Trimble R10 GNSS to iOS and use external position

I want to pair a Trimble R10 to an iOS device and use the location data from the R10 in a iOS app. I found this tutorial and these NMEA Bluetooth settings, but I when I try to connect the iOS device ...
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Will two GNSS modules displace by the same amount?

I am using two gps modules with blunos (bluetooth arduinos) too get the distance between them and display it on a phone. This has worked great and on avg Im getting the expected 5m inaccuracy. However ...
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Can I get ~1cm accuracy with a 2.5m accuracy GPS module and RTCM/NTRIP data after post processing?

I'm a new on this, so I have a subscription to a RTK? service that sends correction data (RTCM/NTRIP) over GPRS/UMTS (you get a SIM card with the subscription) I'm also having a Rover of around 2mx1....
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Coordinate Formatting, trying to convert to GPS

I have a .shp file with a large number of coordinates and I'm not sure how to transform to GPS coordinates. Ideally I'd like to use Python to convert , but have not seen this formatting before: [(...
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How to calculate 2 sigma circular approximation for GNSS positional accuracy?

I'm using gpsd application and I get the positional accuracy related data, i.e., semi-major axis accuracy semi-minor axis accuracy and semi-major axis orientation of the error ellipse. These values ...
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Stream GPS coordinates using D3 and Mapbox

I’m currently working on a project to stream GeoJSON data using D3 and Mapbox. But, I wasn’t able to plot my data based on their types. Basically, I have three different types of GPS data, when using ...
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Showing multiple GPS devices at the same time in QGIS

Is it possible to show multiple live GPS devices at the same time in QGIS?
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Applying correction value to shapefile due to older handheld GPS error in QGIS

I didn't realise that a limitation of an older handheld GPS may be that it would always be off target. After uploading polygon coordinates for a number of areas, I realised that the polygons were ...
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Finding corner start point on map with compass headings

I'm searching for an actual corner point of a piece of property on a map surveyed by the bureau of land management. The corner has headings of N60° 09'E by S29° 26'E How do I convert this point to ...
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Overlapping GPS track data in sea-map mismatch problem. QGIS

Working on QGIS version 2.1817 "Las Palmas" I ran into a spatial mismatch between GPS track data with shoreline data sourced from GSHHS* to make a study site map of an inland sea. The extent ...
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Where to find a someone for QGIS custom programming [duplicate]

I need some custom programming done in QGIS to solve some issues I raised in this question (Separate NMEA String in QGIS for position tracking), as well as some other associated work Where is an ...
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How to convert GPS altitude to other vertical reference systems?

I have GPS positions with altitude and I would like to convert this altitudes to a local vertical reference system. In my case I would like to convert it to DHHN92 (EPSG 5783). I probably want to ...
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How is Trimble Pathfinder Office transforming positions?

I am struggling to understand how Trimble’s Pathfinder Office transforms and exports GNSS data and I’m hoping someone here can explain. I've seen posts like this and this, and documents like this, but ...
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Is it possible to connect using inbuild GPS in new machines with ArcGIS Pro?

We have recently got a set of new machines which are capable of tracking locations using a high-end inbuilt GPS/GNSS support. The machine specifications are shared below: Microsoft Surface Pro 7+ ...
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Under which condition(s) does geopositioning precision infer accuracy?

I am not sure whether this is the right forum for this question but I reckon that since it gathers experts in GIS, the odds of someone having valuable insights is higher than anywhere else. So here's ...
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3 votes
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Separate NMEA String in QGIS for position tracking

I'm using a tracking system that exports positions as NMEA strings output by a single COM port. Each string has a unique identifier ("001", "002", "003") that represents ...
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Input App recording tracks

Is there a way of recording tracks in Lutra Consulting's app in the background? I cannot reckord my track and putting point records in the same time.
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"Rounding" GPS coordinates based on uncertainty range

A stationary GPS receiver will produce a random cluster of coordinate points around its actual location. I can look at previous coordinate readings and apply various algorithms to find the "...
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Identifying if a user is in building or shopping mall using GPS or WiFi data

I am trying to understand if there is a logic to see if a user is in a shopping mall or a building or outside using GPS or WiFi data captured from a mobile phone. Is there a logic to check?
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