Questions tagged [gps]

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

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16 views

How to find similar GPS tracks considering timestamps?

There are around 300 users tracks per day with about 4k points in each with 10s time interval. I'd like to find similar tracks considering location and time. The tracks are similar if it can be ...
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66 views

3D projected map: put locator from GPS coordinates

Hello I'm a newbie in maps and not so good (as I wish to be...) in math and geometrics stuffs. So: I have a 2d google map. I have to put a 2d projection of this map (not exactly this one but a ...
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39 views

Is it possible to merge multiple polylines into one

I have vehicle GPS coordinates of the route. In my case vehicles can drive through one road multiple times, so overall it can look like round trips. Is there any way to merge two traces into one, so ...
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37 views

QField on Android keeps showing my location being off the coast of Africa

I have made a few qfield projects before without this issue, but I can't seem to get around this. I don't think this has to with projection because I'm able to spoof my location from my phone to be ...
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1answer
43 views

How to count the proportion of points in protected areas shape file using R packages?

I have some GPS relocation data and I want to calculate the proportion of those points that fall within protected areas. I'm downloading the protected areas using the wdpar package which uses sf to ...
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42 views

Measure GPS distance between two points without using almost any math? (accuracy not required)

I'm programming an application where I save GPS location (lat and long) into each user info. I need to search the nearest users, I can only search using a between() function provided by my database, ...
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35 views

Google Fit - GPS Data - Download + Aggregate

Is there way to access, download and then aggregate Google Fit GPS paths (example below)? For example, I'd like to take the paths of several walks from the same day, overlay them to create a single, ...
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1answer
28 views

Swift library to convert latitudes and longitudes from EPSG:4326 into EPSG:3857

I would like to know a Swift library or method that I can use to convert from 4326 to 3857. I have referred some libraries such as Proj4Swift and Proj.4, but to no avail. The first link does not has a ...
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Acquire ground coordinates of target while doing aerial survey (airplane or helicopter)

The Problem: Each year I board a small airplane and look for diseased individual trees while flying transects over the forest I help manage. The current method for marking a tree's location is ...
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14 views

Can GPS transmission time be the same for two different ephemerides?

I am seeing a RINEX navigation file where I have two different ephemerides for the same satellite at different times. Nothing surprising. The thing is that they both have the same transmission time, ...
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1answer
29 views

Terrasync “GPS Disconnected” problem

I have a GeoExplorer 6000 series handheld unit. I have a Terrasync 2.52 Serial key and installation disk. I installed Terrasync 2.52 on the handheld unit but upon trying to connect to the receiver ...
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2answers
108 views

Cheap relative positioning

I have a 6 acre permaculture farm, and I would like to be able to plant something at a location, log the location, and be able to find it again to within about a foot accuracy. I do not need the ...
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1answer
35 views

How to transform location data from Lamber (EPSG:31370) to GPS (EPSG:4326)?

Sorry if my way of writing is wrong, I'm a data scientist and I have little to none experience in GIS. I would like to use an open dataset (from http://opendatastore.brussels/fr/ to be precise). It ...
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1answer
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Pathfinder office (ssf) to ArcGIS (shp) projection issue in ArcMap

I'm honestly not sure if that's even the problem but here's what's going on: Collected points with Trimble Geo7X set to NAD83 UTM zone 15N. Post-processed the points in Pathfinder Office, transformed ...
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1answer
39 views

RTK Coordinates from Phone to WGS84 Dec Deg using ITRF00 Transformation and proj4.js

I am attempting to simulate an RTK GPS unit transmitting a CORS corrected GPS location to a phone. The coordinates are in NAD83 (from CORS) but in the phone they are seen in decimal degrees. I need to ...
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1answer
37 views

GPS: what limits the _rate_ of change in altitude?

I have a GPS tracker/transmitter I use in rockets. I use it to locate and recover a rocket. I realize that Altitude is not the strong suit in GPS, and don't expect it to be really accurate. Neither do ...
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1answer
56 views

How accurate are Ordnance Survey MasterMap topography spot heights?

The spot heights in the Ordnance Survey MasterMap sample data over Exeter with feature code 15404 are presented as an integer value in metres. But how accurate are these spot heights? I had assumed ...
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53 views

WSG84, GPS, GEOID and other altitudes

INTRO A bit of tool introduction, but the problem is not related to this directly. I have an app in CesiumJS. I am using Cesium World Terrain, and get altitude using Sample Terrain Most Detailed ...
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1answer
51 views

Trimble RTX GPS NTRIP, DNS failed to resolve IP address

I'm trying to get the RTX correction service going with my Trimble BX992. It is a CenterPoint RTX correction, for which I can see that I am correctly subscribed. I'm getting down to ~0.2m 1-sigma ...
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1answer
27 views

Adding GPS coordinate points to point feature class using ArcGIS Pro

I have a raster, and in ArcGIS Pro 2.4, I created a point shapefile with 830 points. I forgot to specify that I wanted to show the GPS points in the attributes table of each point. However, I need to ...
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1answer
85 views

Can QField record GPS Z-Value

We are a land survey company and are considering using QField to perform asset surveys for local government agencies. Looking through the documentation it appears that QField can do most of what we ...
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10 views

Wrong location in ArcPad

I conducted surveying with ArcPad with Garmin GLO, ArcGIS Collector and Leica Smartnet. After gathering them on a map, only ArcPad (green dot) is away from others, but I don't know why.. Did I have a ...
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34 views

Accuracy of ArcGIS Collector

About ArcGIS Collector app, what's the difference between accuracy in the setting tab and horizontal/vertical accuracy as indicated left-bottom on the map while surveying? For example, if I set the ...
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41 views

Does HDOP correlate with GPS position accuracy?

I collected 1000+ position data from GPS receivers and realized that a position with lower HDOP does not necessarily have higher accuracy. So my question is does HDOP correlate with GPS position ...
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2answers
71 views

Intramaps Roam GPS_LOG not honoring Tracking settings

I have Roam 2.5.2 and enabled the gps_log layer as discussed here: https://roam-docs.readthedocs.io/en/latest/features/Features-2.1/#gps-logging-and-tracking For most part it works well, however it ...
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1answer
45 views

Relationship between Android bearing and iOS course?

I'm a mobile developer working on an Android and iOS app that displays the user's location and various POIs on a map. I've been comparing the location objects that I get back from Android and iOS and ...
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39 views

GPS coordinates are not matching up with street network shapefile despite having same projection

As some background, my colleagues and I used a shapefile of a city's streets as a reference to collect GPS data. They were written simply with a field for: street name, lat, and long. The many points ...
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31 views

How to separate journeys from GPS traces using ArcGIS/ QGIS?

I am facing a GPS Data Preprocessing problem. I have GPS traces of buses which traveled from one place (bus station) to another. This file contains relevant (eg:- Data recorded between the starting ...
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1answer
39 views

How can I count the number of countries my GPS data fall into?

I'm working with GPS data in R from different studies and would like to list the countries that each study covers. I can easily map the data using leaflet but I'm not sure how to extract the countries....
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2answers
57 views

Ignoring ellipsoidal heights recorded from GPS when only interested in location?

I am not interested in converting ellipsoidal height into AHD heights, because I have a good DEM. However, this whole business about geocentric vs geodesic coordinate systems is thoroughly confusing ...
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1answer
117 views

Cleaning GPS tracks from large jump / outliers

Can someone please explain the steps to take in order to eliminate the parts of these linestrings which jump across large distances (not along with the road network)? They were created from GPS ...
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13 views

Map GPS coordinate to nearest street [duplicate]

I have an application where I receive GPS coordinates of different vehicles. Those coordinates are displayed within JXMapViewer on an OpenStreetMap. However, some devices have a bad accuracy and so ...
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1answer
46 views

Options for precise relative position calculations

I'm investigating an industrial application that has a requirement to calculate with precision the relative distance on the ground between two outdoor points in the following scenario: The first ...
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21 views

Forgot to do calibration on Trimble GPS

I collected the location measurements using Trimble GPS but forgot to do a calibration since I have done that a month or so ago at the same location and I thought that I don't have to redo again. I ...
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30 views

Reading NMEA frames on i2c device?

I have a linux machine which is connected by I2C to a F9P Ublock GNSS device. I need to get the GGA frames and some custom Ublocks frames from I2C, do some calculations and forward them to UDP. Is ...
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1answer
94 views

GPS Hardware for QGIS

I have the same question as this one posted 3 years ago. I use windows 10 and USB 3.0. I have seen a lot of angry reviews about well known GPS device brands so I was wondering if anyone has been ...
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26 views

Do extra zeros change the coordinates for decimal degrees?

At my work we require contractors to submit work reports in decimal degrees with 6 decimal places, i.e. the location of where they paved roads or put in a road sign. The question is, contractors have ...
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Create ltraj in adehabitatLT Error

I'm trying to use adehabitatLT analyze animal movements. However, I'm having issues with creating a ltraj object in R. I have followed the as.ltraj() example in the documentation and I'm getting this ...
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83 views

Calculating Center (GPS Point) and Radius (km) of n GPS points

I'm new to GPS and position mapping but i have a background in programing and some of the math related to it. I've been tasked with writing a small golang program that takes n GPS points (DMS) and ...
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34 views

Display all trajectories location along with dummy location

I'm trying to display the all trajectory location on Google map along with dummy location. I have tried to display dummy locations with sample location and it works fine, but when I try to connect to ...
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0answers
31 views

Fusing position data obtained from one coordinate system with other sensor position coordinates? [closed]

I'm using data from GPS and from vehicle sensors (Ultrasonic) separately to track the position of a vehicle using Kalman filter. I want to implement sensor fusion for the received measurement data and ...
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0answers
34 views

Converting latitude/longitude into a slab number (or item number) and vice versa?

Purpose: To compress the data transmission for the longitude and the latitude. Initially these datas are in the form DD.MM.mmmm: degrees, minutes, ten thousandths of a minute. Latitude stands under 28 ...
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20 views

Random and systematic error of GPS or barometer based altitude measurements

All measurements have error, but not all errors are the same. Measurement errors may be: Totally random (noise), in which case averaging measurements reduces error. Totally systematic (bias); if the ...
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1answer
112 views

Is the GPS signal being scrambled near military bases

We are navigating our survey aircraft using standard GPS receiver. Sometimes we fly near the vicinity of US Ramstein military base in Germany and it seems we are losing lock (no solution) in that area ...
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0answers
98 views

What is causing this shift in coordinates?

I'm working on taking raw GPS measurements and getting a position from them. It involves double differencing measurements from a fixed base station (with a known position) and a rover (in my case, an ...
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35 views

Loading a georeferenced GIF with an OziExplorer Map Data File into a Garmin GNSS receiver?

I have a map as a Graphics Interchange Format (GIF) file and an associated American Standard Code for Information Interchange (ASCII) file which has a .map extension. The content of the ASCII file ...
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1answer
260 views

Correction of GPS-Track, snap to road (line, network)

Problem as shown in the image: I like to correct the GPS track (orange) to the right road (black). In a network of roads it is difficult to snap to the right path - for human it's obvious which one ...
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2answers
42 views

Android app to get altitude of places to use in field visit?

I want to verify the height of the ground which is provided to me with the help of an app if available. Of course, I am aware an app will not give me exact value but for me, it works if it shows ...
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38 views

Converting geocentric coordinates to geodetic coordinates?

I would like to start by saying that I am very new to this. I have 160 different points which all have similar layout as below: at point | X= 153346.357 | Y=354912.111 | Z=0 | Doing some research I ...
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1answer
38 views

Turn string data (of GPS coordinates) into a GPS tracker = frozen map. QGIS2.14/Py2.7/Win7/LAN

I am currently involved in a student project which is to turn string GPS coordinates into a GPS tracker. This is my current work: First, the UDP data is shared through a LAN (No internet available) ...