GPS is a space-based satellite navigation system that provides location and time information.

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15
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2answers
9k views

What is the difference between triangulation and trilateration?

Looking around I noticed that many people exchange the terms (tringlulation and trilateration) for the same sense. What's, actually, the correct sense of Triangulation and what are the differences ...
1
vote
0answers
871 views

convert GPS to XY coordinates

if i have obtain GPS coordinates as Latitude/Longitude, then i need to convert them to XY coordinates, i see this link actually i need to get the Trilateration , in its equation i need the XY ...
0
votes
0answers
30 views

A machine to measure latitude to 6 decimal places of a degree [duplicate]

I am doing a PhD research project to do with medieval and ancient archaeoastronomy which requires me to be able to measure latitudes up to an accuracy of 6 decimal places of a degree of latitude. ...
2
votes
1answer
194 views

Why are Garmin provided maps inaccurate?

Collected tracks on my Garmin GPS (Oregon 450) or in BaseCamp seem to be not in the correct position. There's only a little detail with major highways but it looks as though the route is shifted ...
5
votes
3answers
967 views

How to transform GPX-tracks into elevation-tracks with any GIS?

I have a GPS track in GPX format available from a recent bike tour and I need and want to do some analysis on the tracks. I'm wondering whether there is any way to transform the GPX data into an ...
3
votes
3answers
679 views

GPS drift during the receiver is stationed

I have developed a GPS Tracking device it is working fine when the receiver is in motion, when it stationed in a position for couple of hours i get some drift for around 10-15meters. The receiver send ...
0
votes
0answers
70 views

QGIS GPS live tracking adding polygon vertices

Maybe I'm missing something or maybe it is a bug? I'm trying to add polygons using the GPS information console. The only button available to record data is "add polygon", but if you click on it, you ...
0
votes
1answer
54 views

error in estimate distance?

i do some experiment place two sensor node between them 4 meter as distance. then i get these GPS information: node1: Latitude: 32, 33.255 , Longitude: 36, 0.6632 node2: Latitude: 32, 33.228 , ...
10
votes
5answers
7k 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 ...
2
votes
1answer
124 views

Finding intermediate points and speed over a segment

I have a dataset which is in the form of ( Time , Car ID, Speed at that moment, Lat,Long) and I need to do some machine learning on the data to answer the following questions : Best route from ...
1
vote
1answer
242 views

find euclidean distance in GPS [duplicate]

i need to find the distance between two gps location, So i think to do this: lat1(seconds)-lat2(seconds)=lat * 30.7151 == distance latitude in meters =Latm long1(seconds)-long2(seconds)=long ...
12
votes
3answers
5k 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 ...
0
votes
2answers
156 views

I can not download gpx from GPS through GPS tool with GPS babel on QGIS

I have already install GPS tool plug-in and GPS Babel. Garmin GPS map 62s is connected my PC through USB cable. I changed device setting according to below site. ...
6
votes
1answer
227 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 ...
0
votes
1answer
80 views

Imported GPS data does not overlap with map

I´m working on QGIS and I geocoded 2 addresses of a city in Germany and tried to input the text-file as a layer. It worked, but the 2 points must be in the map of the city and if I zoom to the ...
3
votes
3answers
133 views

How long for surveying quality GPS to get accurate 3D position information

I recently read an Ordnance Survey Blog article that seemed to suggest that it was necessary to leave the GPS device in use for four hours to gather requisite data. I am aware that "domestic" GPS ...
3
votes
1answer
359 views

Is machine learning used much in GIS?

I'm new to GIS. Is machine learning used much in this field, and where? I'm investigating a job opportunity with a mapping company working on traffic awareness. My background is in supervised machine ...
0
votes
0answers
119 views

Download/Upload GPS/Qgis don't work anymore

We were using Qgis and GpsBabel to download waypoints and tracks from GPS garmin 60 or 76. Since few weeks, this is not working anymore. There is a error windows, and nothing is created. I tried ...
0
votes
1answer
1k views

How can I manipulate the timestamps in a GPX file?

I have a GPS tracked stored in a GPX file. Now I'm looking for a tool that allows me to set the start time of the track and the duration, and the tool should automatically evenly distribute the ...
6
votes
3answers
2k views

Garmin etrex raster maps support

I currently use an excellent set of printed topographic route maps for mountain biking. I would like to scan the maps, georeference them, and upload the maps to a handheld GPS device. Does the etrex ...
2
votes
0answers
269 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 ...
1
vote
0answers
38 views

Twitter live feed on ArcGIS desktop [duplicate]

I am a complete beginner with ArcGIS and i have been looking for a way to live feed tweets to ArcGIS desktop. A quick google search brings this blogpost up from 2009: ...
5
votes
2answers
639 views

Storing GPS tracks with timestamps in PostGIS

I need to store a series of GPS points with timestamps in the database (traces of various vehicles). I am wondering which of two approaches to choose for storing them in the PostGIS table: 1.) Each ...
8
votes
4answers
914 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 ...
1
vote
2answers
117 views

QGIS Holux gpx file doesn´t show up

I´ve got a problem with displaying the imported gpx file. The gpx file is created in Holux Funtrek 130 PRo. The map I use is from Openstreetmap, I am sure it is the right map from the location I ...
0
votes
1answer
260 views

Looking for a tutorial on syncing QGIS with Trimble ProXT

Does anyone have any experience/advice to sync a TrimbleProXT gps antenna with the current "Lisboa" 1.8.0v? Additionally did you manage to collect features (points,line,polygons) in the field ok? ...
2
votes
0answers
78 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" ...
4
votes
1answer
126 views

GPS Elephant Tracking II: Is ArcGIS basemap imagery orthorectified?

-- For my original question and pictures of elephants wearing GPS equipped anklets, go here. -- I'm experimenting with the use of GPS anklets to track the movement of zoo elephants. This has proved ...
10
votes
1answer
486 views

Overview of GPS tracking system technologies

Background: I've been asked by a friend to estimate the cost of setting up a GPS tracking system for a small fleet of buses, so we can do real time reporting of bus locations via a webmap. In my ...
3
votes
2answers
210 views

Several questions about using spatial data?

If you have spatial data for SQL server, can you use the spatial data (both geometry and geography) in another application for instance ESRI ArcGIS? Is spatial data a standard that every GIS ...
12
votes
4answers
3k 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 ...
0
votes
1answer
55 views

Is it possible to download GPX another coordinate system except WGS(GCS) with GPS Tool on QGIS1.8.0?

I got GPS data with using bessel1841 as coordinate system. When I download GPX data on GPS tool, it is automatically treated as WGS84. Can I use another coordinate system when I download GPX on GPS ...
2
votes
1answer
457 views

Where can I find Foursquare Datasets?

I'm doing research which aims to analyse location based social networks. So the Foursquare dataset is suitable for me. Is there any Foursquare dataset available? I need 4 information in the dataset: ...
13
votes
3answers
8k 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 ...
5
votes
3answers
115 views

Can I access Trimble logged positions in ArcMap10?

We recently walked a fence perimeter with a Trimble Ranger, auto-logging positions at 5 second intervals in a generic point file. The exported file acknowledges over 800 points, but only displays the ...
0
votes
1answer
83 views

Alternate option for a Data Player plugin for GPS in qgis

I found a plugin for QGIS to play a GPS Track. (Data player plugin).The Problem is I can not read .gpx File with this plugin. Is there another option?
4
votes
3answers
385 views

Wildlife surveys using tablet and GPS, import/export to/from ArcMap

I've found some info about this on a previous post (Advanced android app for mapping and GPS logging), but it didn't provide enough info, I'm hoping some other tech experts can help! I have a tablet ...
2
votes
0answers
98 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 ...
4
votes
1answer
406 views

How to show a geoTiff on an iOS application?

I'm developing an iOS application that will use offline maps. These maps are on GeoTiff format but I don't know how to do it. I've found this question: How to display a GeoTIFF on mapView but it uses ...
7
votes
1answer
372 views

real time map matching

I am working on a project which requires real time map matching. I am currently using ArcGIS but not sure whether it will work. Here is what happens with my system: the cell phones sent GPS fixes ...
0
votes
1answer
626 views

How to fix the QGIS for Android GPS panel?

I have installed qgis on my samsung galaxy s1. But I cant test the gps. I found how to turn the gps on, but I cannot open the gps pannel to do it. When i press view->panels there is nothing happens.
6
votes
2answers
2k views

Accessing GPS data with JavaScript in real time

Is it possible to access GPS data in real time on a smartphone with JavaScript (without an android or ios application I mean)? Thanks
2
votes
1answer
152 views

Keyboard shortcut for GPS data capture in QGIS

I would like to setup keyboard shortcuts for GPS data capture with QGIS. Using GPS Information dialog box, I could use Mouse-Left-Click to "Add feature" and "Add track point", but I would like to ...
19
votes
3answers
19k views

What are the major differences between GPS, GLONASS and Galileo?

What are the major differences between GPS, GLONASS, COMPASS and Galileo?
3
votes
1answer
221 views

Join GPS points obtained from .GPX file in Python Console

Having loaded the .gpx file into a new layer from python console, I'm unable to access the gps points in the attributes table. Essentially, i'm unable to join these points to form a polygon ...
7
votes
1answer
154 views

Unable to load .gpx file from Python Console

I'm trying to create a plugin which will extract the gpx files and load them onto the active layer window in QGIS. While I'm able to load it using the QGIS GUI from Layer>New Vector Layer, I'm not ...
5
votes
1answer
289 views

Why are points collected with a Trimble FM 750 off by more than a mile when displayed in QGIS?

I have a grower that has a FM 750 and is trying to make points in a field. When finished he takes the file out of the display and goes to his computer and he can bring up the points in the right ...
4
votes
2answers
318 views

Tracking a vehicle without GPS device

We are planning to write an application which have to track the user driving in his truck in the cities like New York city accurate upto which lane he was driving on. In the cities with those tall ...
1
vote
2answers
547 views

Exporting shp into a GPS [duplicate]

Possible Duplicate: How to convert .shp into .gpx using QGIS? I'm trying to convert a shapefile with some random points into a gpx file, but I'm having some problems: when I upload the gpx ...
5
votes
2answers
1k views

How to merge multiple file geodatabases into one file geodatabase?

I have created a file geodatabase that has several feature data sets, feature classes, and domains. I have created a map with the file geodatabase added to it, converted the map to ARCPAD AXF format ...