Global Positioning System (GPS)
7
votes
11answers
1k views
Logging GPS and Accelerometer Data - Device Suggestion?
I am looking for a device that can track my location (lat,long) and speed all day long. Perhaps, I need GPS and accelerometer data bundled together.
What I want to do is to log my daily activities. I ...
1
vote
1answer
639 views
How do I calculate ECEF X,Y,Z velocities for GPS if I have no satellites
I'm attempting to simulate a GPS message where know variables are starting location, ending location, speed (m/s), and a bearing (0 - 359 degrees). How can I calculate the ECEF X, Y, Z velocities ...
15
votes
6answers
761 views
Sources of realtime spatial data
I'm trying to set up a demo that serves up live spatial data, but am having trouble finding any suitable example data sources.
Ideally I'm looking for something that updates every few seconds; either ...
8
votes
10answers
1k views
Need a Benchmark GPS Trajectory data-set? Anyone?
I'm looking for a benchmark GPS data set, available for research purposes for free. I've found GeoLife GPS Trajectories dataset from Microsoft Research but I find it a little incomplete.
What I need ...
10
votes
3answers
3k views
Post Processing GPS Data with open source software
I am using Magellan Professional Mapper CX working on ArcPad 7.1 platform. It has sub-meter accuracy after post processing. Without post processing the data collected in the field is off by 10 to 15 ...
11
votes
3answers
2k views
What is the maximum Theoretical accuracy of GPS?
I was talking with a potential client, and they requested that we plot some points with GPS, with a maximum (or should that be minimum?) accuracy of 2 m.
This is an area with no WAAS, and I was under ...
11
votes
7answers
547 views
Mobile Data collection options
What COTS software is available to do mobile data collection, with GPS positioning. Map display not required. I'm looking across the board (platform wise).
I'm already aware of...
ArcPad
ArcGIS ...
8
votes
4answers
455 views
How to build a geographic database of GPS logs?
On our aerial wildlife surveys we typically generate dozens of GPX files, and usually convert most of them into shapefiles for display in a GIS application. GPX files are a terrific way of keeping all ...
4
votes
3answers
597 views
Mobile, Offline viewer for geographic data
Currently, field crews consumer geographic data via laptop (no internet, no gps). ArcReader.
I would like to get them shapefiles (or some derivative of a shapefile) on a mobile platform (smartphone) ...
3
votes
2answers
2k views
Using OpenLayers (with OpenStreetMaps) and PostGis for rendering data acquired from GPS tracking device?
I'm researching and planing to acquire data from GPS device and store them in postGIS database, then use geodjango to process/work them out and finally chart them on a map with OpenLayers.
Will these ...
10
votes
5answers
5k views
Convert XY points to a line?
Someone mistakenly saved a GPS track as waypoints and then sent them along to me in a .csv file. They want a line back (shapefile). What's the simplest method to convert this to a line? Available ...
6
votes
2answers
330 views
Managing error with GPS routes (theoretical framework?)
I'm looking for the appropriate theoretical framework or speciality to help me deal with understanding how to deal with the errors that the GPS system has - especially when dealing with routes.
...
16
votes
6answers
2k views
Is there a good GPS track analysis library?
I keep writing custom code to work with GPS tracks: GPX files and NMEA logs from my phone, dedicated GPS logger, etc. I feel like I'm reinventing the wheel and am wondering if there's some standard ...
17
votes
6answers
1k views
How correct is the “Accuracy” value given by GPS devices?
I have a Garmin Forerunner 305 and a Google Nexus One Android phone. From the GPS on both these devices I can get a "Accuracy" value that is usually between 6-20 meters. How much can I trust this ...
12
votes
5answers
2k views
How to get an elevation profile for a gps track?
I'd like to get a reasonably accurate elevation profile for a track recorded with a GPS (which often has very unreliable altitude data and occasionally none at all, depending on the model.)
Does ...
10
votes
4answers
2k views
Clustering Trajectories (GPS data of (x,y) points) and Mining the data
I've got 2 questions on analyzing a GPS dataset.
1) Extracting trajectories I have a huge database of recorded GPS coordinates of the form (latitude, longitude, date-time). According to date-time ...
25
votes
7answers
1k views
Why don't they use cell towers like GPS satellites?
If my understanding is correct, a GPS satellite produces a pretty simple signal which is basically composed of its location and its time. Given 4 of these signals, then one can uniquely solve for the ...
15
votes
3answers
497 views
Lightsquared GPS controversy: Where is the analysis?
GPS World reports that Lightsquared's network of 40,000 transmitters will interfere with GPS signals.
Initial technical analyses have shown
that the distant, low-powered GPS
signals would ...
8
votes
1answer
332 views
How much sense does it make to average (lat,lon) samples in order to increase 2D accuracy of a GPS location?
Several GPS applications, like this one, or this one, acquire multiple (lat,lon) samples of a given location, assuming that the GPS unit is not moving, and then take an average of the samples in order ...
11
votes
3answers
2k views
Advanced android app for mapping and GPS logging
I am looking for an android app able to log GPS data like coordinates, altitude, current speed and would be nice if also the GPS accuracy/number of satellites. Many GPS apps are able to display these ...
12
votes
3answers
452 views
GPS Elephant Tracking: Utilizing A-GPS, WAAS, DGPS and Understanding HDOP, NSAT, and ZDA
*I'm using a GPS data logger (qstarz bt-q1000xt) to track the movement of zoo elephants, and I have a variety of technical questions. I've had limited success receiving answers from the vendor. You ...
7
votes
1answer
134 views
Analysis of GPS error
I'm wondering if there have been any studies which attempt to analyze or characterize GPS error distribution over different situations/conditions (e.g. surrounded by tall buildings/mountains, ...
6
votes
2answers
754 views
Trimble GeoXH vs GeoXT and GPS Correct
I am about to purchase a new GPS unit. I currently have a GeoXT and have used the combo of GPS Correct/ArcPad with GPS Analyst/ArcMap to correct the collected data to submeter (or close to it).
...
3
votes
3answers
3k views
Distance between GPS coordinates
Given a database of GPS points, a center GPS location, and a radius R (in meters), how can I find all points in the database that are within a distance of R of the center point?
Will the distance ...
3
votes
1answer
152 views
How can a single line be computed from multiple possibilities
I have datasets containing continuous GPS streams of data that represent routes or trails. For any given route, I probably have at least 5 (in some cases many more) different sets of data. Given that ...
6
votes
4answers
594 views
How to filter wrong GPS points?
I have a database of GPS points. There aren't any tracks, only points. I need to calculate some value for every 100 meters, but sometimes GPS gave a wrong coordinates that lies far from real GPS ...
6
votes
1answer
648 views
How to filter wrong GPS readings?
I have absolutely no experience with GIS, it just so happens that one of the hobby projects I am doing at the local hackerspace includes tracking a model boat with a GPS... I hope this is the right ...
5
votes
1answer
150 views
Simulate (Mock) GPS Tracks
I have the following scenario:
1) I need to create GPX files for use in testing of a mobile device.
2) The tracks to be described within will span large distances over long time periods (i.e. it's ...
3
votes
6answers
1k views
Garmin GPS 78 Interface
Does anyone know how to interface a Garmin GPS 78 Marine GPS with their computer to manage waypoints (upload, download, save, etc.) Previously I was using the MN DNR Garmin tool, but it no longer ...
6
votes
3answers
2k views
Calculate maximum speed from GPS data
I have raw GPS locations for a track, and need to get maximum speed. Simple methods (calculate speed between 2 points, take max) will give meaningless large numbers due to GPS inaccuracy, the point is ...
4
votes
1answer
3k views
How to batch convert Garmin GDB to GPX?
I need to convert a lot of garmin GDB files to GPX in order to convert it to another vector format. Is there any tools available can do a batch convert from garmin GDB files to GPX? Using MapSource ...
1
vote
1answer
1k views
Difference between Garmin eTrex Legend HCx and eTrex 30?
I have used etrex Legend HCx a lot and been satisfied. Now I've seen etrex 30 just for a while and it seems to me that the Legend is much more user friendly, good old menus with a lot of ...
0
votes
1answer
127 views
convert GPS to x,y using reference node
i am using sensor nodes and their antenna to calculate GPS coordinates as notation of (degrees/minutes/seconds), i have some question of how to do these things:
how can i convert latitude and ...
