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

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241 views

GPS data based track/trip calculation algorithm available?

Currently I'm receiving position data of moving assets every 90 or 120 seconds (depending on the asset). What I'd like to achieve now is to detect standstill and movement phases (tracks/trips) on the ...
4
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739 views

Microsoft Surface vs. iPad for mapping

I was recently introduced to the Avenza PDF app for iPad and I've been using it in the company I work for to help our field crews find their way around, and record waypoints and tracks. The app takes ...
3
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158 views

How to determine and send alert SMS for next bus stop in a GPS tracking system?

In my gps tracking system (PHP/MySql) I have got 5 Stops for a vehicle. Whenever the bus reaches stop 1, the passengers at stop 2 should get an SMS alert. And in the same way for the sops followed ...
3
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62 views

what criteria should I consider in buying a pocket GPS

It's my first time making this kind of choices, and I really don't know how to go with a choice or another. I basically know that it should have good durability , a good battery life and good ...
3
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104 views

Ways to measure similarities/congruence of tracks (point features) in ArcGIS

I have a sets of GPS coordinates recorded while tracking different cross country runners. What I would like to do is to compare how similar the tracks of the individual runners are. Is there a test ...
3
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260 views

QGIS: GPS Tracking with improved Altitude

I am preparing for archeological fieldwork in Sudan. I recently came up with RTK equipment and software using RTKlib to export the real time corrected data (cm level) to QGIS via a simulated NMEA ...
3
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384 views

Are there any shapefile-based GPS data recorders?

I am looking for a data recorder that can be programmed to send a serial data request to a field computer and then accept and record an incoming data string and tie it to GPS location and then save ...
2
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38 views

Good GPS navigation app for iPhone with downloadable OFFLINE maps?

I am looking for a good GPS navigation app for my iPhone that will work away from wifi and cell coverage (GPS only) and thus allow me to download offline maps. Paid app is OK. Must Have features: ...
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23 views

Trimble pathfinder data dictionary default value exclusion

Is it possible to have a numeric attribute in trimble pathfinder without having to use a default value? I am trying to make a numeric attribute compulsory to fill in BUT because the data dictionary ...
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40 views

How to measure RTK accuracy of a moving vehicle?

I am currently working with tractors using a RTK enhanced automated steering system. One of the biggest problems is that even RTK can have a inaccuracy of 2cm. This can be too much for some possible ...
2
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74 views

About Timestamp in Geotagging

I'm on my reasearch for GPS and sensors integration. I've just wondered that to integrate between GPS and camera you need time offset synchronize which called as a timestamp. But how does software ...
2
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47 views

How do I accurately measure a gps track over a long distance?

I am measuring the length of the Continental Divide Trail that goes from the Mexican border to the Canadian border. I have a .gpx file of the entire route in NAD83 with tracks about every 50 meters. ...
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67 views

Create “mean” line from multiple lines using QGIS

I have multiple lines features (also have them in multipoints...) representing similar path (mountain trails, in this case) with various GPS precision, resulting in many lines close to each other, but ...
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34 views

Reference and Beacon Stations in Vietnam

I'm not sure if this question can be asked in this forum, but here it goes. I am on my way to conduct some remote sensing research in Vietnam, which includes logging of coordinates. This should ...
2
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82 views

How can I store height info from GPS in QGIS?

I want to use QGIS as a tool for collecting GPS-Data in the field. One use case would be simple surevy tasks where I want to store the three dimensional position of points. QGIS is working fine on the ...
2
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104 views

Is it possible to display labels in background files (.imp) on Trimble GPS units?

I have been trying to figure out if this is possible for a while now. I know if you load a file in as a data file, you can click on a feature and the label will pop up. However, you cannot view a data ...
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136 views

Calculating Distances between coordinates

I have perused through the other questions that are very similar to mine but am still having some trouble. I have 75 coordinates in WGS84 that I brought in from an Excel table. They are now on my ...
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138 views

best free easy GPS software? (not necessarily 'real' GIS)

Our search and rescue group is looking for some advice on what free and user-friendly (no computer savvy required) software folks could use to interact with their own GPS. Doesn't have to be a 'real' ...
2
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47 views

Calculate Moving Time

I am wondering how web apps like Garmin connect or Strava calculate a "moving time" from a gps track. For example I might record a GPS track on my Garmin GPS that has an elapsed time of 5:34:26 but ...
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292 views

GLONASS Satellite Position Prediction using Almanac Data

GLONASS ICD has a section named "Algorithm of calculation of satellite motion parameters using almanac". It gives the formulas in order to calculate the position and velocity of the satellite. ...
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222 views

how to make decent sense from scattered river depth measurements

I sampled river depth at scattered positions and I want to be able to make a map and GIS layers out of it. My problems are: As the river meanders the interpolation I do in scientific packages i,e. ...
2
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0answers
183 views

Should 2D Positions and 3D Positions be considered conceptually different entities?

Let's suppose we want to model GeographicPositions, described by coordinates or coordinate tuples inside some Coordinate Reference System. Also, these would be put inside some sequence to represent ...
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358 views

calculating bounding box from known centre coordinate and zoom

I have a map, the centre of that map (centrepoint) is = -37,175 ( gps) I know the zoom of the map = 13 I know the size = 320x320px I know there is 111111m in a degree of latitude and a varying degree ...
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103 views

How can a GPS receiver know the estimated error?

I would like to plot a circle of possible error on the map in a GPS app. From http://en.wikipedia.org/wiki/Dilution_of_precision_(GPS), we can see that GDOP is equal to "delta of output location" ...
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141 views

Interpolate current Course value of GPS using previous Course values

I have a set of GPS data with Lat, lon and Course. I need to interpolate current value of course, using previous values of Course. The formula I am using is not accurate in curves.In C language I was ...
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163 views

QGIS on android4 with bluetooth GPS

I'm trying to set up a moving map on my tablet (asus, Android 4). I've installed QGIS (latest version), which works. I've got a blue tooth external GPS, which I've paired to the tablet. However, I ...
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158 views

From gpx to line segment 1Km using ArcGIS 10

I have gpx files containg points with attribute data such as time and date. I'd like to convert them into lines, and that is not a problem, but what I want to do is create 1Km segments with time and ...
2
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234 views

How would I modify GPS tracker to accept two nmea inputs and gpsmarker to include a heading vector?

I use QGIS on a research vessel and wonder whether I could modify the QGIS 1.8.0 gpsinformation widget. I want to achieve two things. 1. Change the GPS marker to a boat shape which points in the ...
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177 views

How to enable OSM map in Garmin?

I've installed two OSM maps, but I cannot use them in Garmin. See the window of Utilities / Manage Map Products: The maps are not lockable, but I cannot use them in Garmin... What shall I do to be ...
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133 views

How to configure various client applications to display AVL data?

Given x number of GPS units transmitting NMEA formatted strings back to a server (xxx.xxx.xxx.xxx:xxxxx) is there a way to listen in on the traffic and parse NMEA formatted strings for display on a ...
2
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467 views

How to read a .GPB file in C#?

I have a .GPB file, I need to extract the common GPS data from it but I don't find a clear structure that specify the contents of that file. as a sample record from file 00000260 02 11 A9 61 E7 96 ...
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53 views

Deriving length values from GPX files in QGIS

I’m missing something real obvious and I apologize for revisiting a topic addressed in several Q&A’s here. I’m an experienced GIS user (not programmer) who’s new to QGIS (can’t afford Arc in ...
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36 views

Conversion of (lat, lon, height) from GPS to another CRS

I have latitudes, longitudes and ellipsoidal heights derived from GPS readings, referenced to the ITRF08 system with vertical datum (CGVD2013) - http://webapp.geod.nrcan.gc.ca/geod/hmod/hmod.php How ...
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0answers
24 views

Given raw NMEA data, how do you estimate accuracy on-the-fly?

I have streaming NMEA data from a GPS device to my application. One of the sentences includes HDOP. I previously calculated the circular error probable (CEP) for this unit. How can I calculate the ...
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35 views

How do I compute uncertainties in the positions transformed using Helmert transformation?

I am familiar with Python, MATLAB and Mathematica. My data is given by Cartesian coordinates (positions in X,Y,Z (meters), standard deviations XX, YY, ZZ (meters) and a correlation matrix (XY, YZ, ...
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21 views

KML To Automobile GPS

I've created a bunch of Placemarks and have them in a kml file. Is there a way to get this into the GPS of a car?
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33 views

Data Collection Solutions

I am seeking a new data collection software for a team of biologists who track migrating animals from planes through aerial telemetry. I currently use Delorme TOPO USA but when collecting point data ...
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133 views

Can I put a button that automatically inputs GPS coordinates into a google form? (or other spreadsheet populator)

I am currently creating a Google Form and part of the questionnaire requires the user's current GPS location. Is it possible for a button to be able to do this and automatically populate the field? Or ...
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151 views

Collector for ArcGIS PDOP and GPS collection configuration settings

My company just acquired a Geneq SXBlue II GPS receiver to pair with an iPad and the Collector for ArcGIS app. The functionality is awesome and loved by everyone, but since we have biologists on our ...
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13 views

Base station correction process

This concerns post-processing via base station correction in Pathfinder Office. I understand the base station is a known location and the GPS receiver's location is corrected relative to the base. I'm ...
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0answers
101 views

Available modules/products for GPS+IMU sensors shipped with sensor fusion SW?

Are there any solutions/products (modules) in the market that integrate GPS and IMU sensors that come together with the sensor fusion algorithms (Kalman filtering etc.) implemented and ready for use? ...
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31 views

ArcPad GPS Data Captured misaligned

Data captured using ArcPad 10 is not displaying properly. The .shp file created in arcpad is diplaying a NAD 83 Zone 17 projection. From what I've been reading, the datum for GPS is usually in WGS ...
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201 views

Calculating distance in m in xyz between GPS coordinates that are close together

I have a set of GPS Coordinates and I want to find the speed required for a UAV to travel between them. Doing this by calculating distance in x y z and then dividing by time to travel - m/s. I know ...
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56 views

Calculating new satellite position given pseudorange measurements

I'm looking for a reference/text for an explicit formula to calculate a satellite position given pseudorange measurements from later epoch times. I've seen a lot of matlab code on the internet but I ...
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0answers
51 views

GPS with QGIS--what happened to the capture point?

I have been using QGIS for years but when v. 2 came out and important functionality seems to no longer work. In 1.8 the "capture point" or "capture line" buttons on the GPS panel would work. Ever ...
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0answers
60 views

Why does the postGIS file lose geometry?

I am loading shapefile data from a GPS into PostGIS via Leica ZenoOffice. This apparently imports fine with it's geometry in the attribute table. However, when I add a postGIS layer in QGIS the file ...
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1k views

Translating hdop, pdop and vdop to metric accuracy from given NMEA strings

How can I translate dilution of precision to a metric unit? For example: say I got 1.2 in hdop from NMEA sentence of my GPS receiver, in what should I multiply to get a metric accuracy? Just like the ...
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94 views

How does Mobile GPS work in Windows Tablets?

Can anyone tell me how GPS chips generally works in Windows8 Tablets? As far as I can tell Tablets do not have a separate GPS chip like those in handheld GPS receivers - It seems to be combined into ...
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62 views

I'm new to GPS, and I had a quick question about clarity.

I'm working on a project for class, and I'm mapping GPS on Google Earth with a KMZ file. I used a handheld GPS 24°6.691'N + 74°27.833'W. How accurate is my coordinates? I know I'm in decimal ...
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22 views

How does a GPS satellite knows which gps receiver asked for it's location?

GPS satellites get a lot of requests for information from many different devices, so how do they know to return the information to the right receiver?