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

learn more… | top users | synonyms (2)

0
votes
1answer
1k views

Does GPS Navigator send data to Satellite?

Does GPS Navigator send data to satellite? Is this true about regular devises available in the market?
2
votes
1answer
80 views

What operations do the GPS recievers perform after capturing signal from Satellite?

What are the operations on the signals recieved by a GPS reciever ? How does it process them towards achieving a position fix ? I need explanation with the decoding and correlating part of the ...
0
votes
0answers
169 views

MapFish Print latitude, longitude innacuracy?

I'm new to GIS so this may be trivial: I'm using MapFish Print to create some PNG. I have issues to place the viewport. When I use a random GPS coordinate: -20.904522,55.475106 which seem to point ...
6
votes
1answer
306 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 ...
1
vote
2answers
359 views

QGIS GPS position after entering attributes

I would like to be able to fill a form and, before, during or after, be able to cath a GPS point. I already know the GPS extension but I have to catch the point and enter attributes after... Idea how ...
2
votes
2answers
683 views

how to make a line from a set of gps points?

As a part of my research I need to create the trajectory of respondents according to the their collected GPS data (including X and Y). I am familiar with python programming, but I am a beginner in ...
10
votes
4answers
2k 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 ...
1
vote
0answers
197 views

Building a private GPS almanac server - practical experience

I'm trying to provide a source of GPS almanac files (in SEM format) for a non-connected / sometimes connected network. I know that I can download them from the USCG NAVCEN. However I don't want to ...
0
votes
2answers
2k views

Precision of x decimal points in meters? [duplicate]

Is there a handy reference that corelates the number of decimal points in a coordinate to the precision in meters? I had discussions like "4 decimal places will place you within a 500 meter radius" ...
2
votes
3answers
2k views

Local Coordinate to Geocentric

The ultimate question, I need a transformation matrix to take a point in local space representing a roughly 500m x 500m place in New Mexico centered at -108.619987456 long 36.234600064 lat. The final ...
4
votes
3answers
1k 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) ...
2
votes
1answer
134 views

interfacing multiple gps

I am trying to interface NMEA output of multiple GPS units transmitting wirelessly to a single PC, each GPS position can then be shown on georefance map of that area. My question 1.) How to ...
4
votes
2answers
390 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 ...
4
votes
1answer
2k views

Distance calculation : Integrating incremental gps data

I am trying to build a GPS based odometer based on android. Currently , I am calculating incremental distance changes very frequently ( < 5 meter movement). The distance calculation in android is ...
1
vote
1answer
439 views

Determine if GPS coordinate in Canada

I have GPS tracking solution and most my customers in US. My reverse-geocoding solution pretty basic: Table with US ZIP database Procedure in SQL Server where I search for city/state closest to ...
1
vote
0answers
120 views

Get GPS way points to exact place

I added some GPS way points on land use layer. but way points are not in exact place.(Way points are located at little bit away from exact place) I want to adjust way points to exact place. GPS was ...
2
votes
0answers
162 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 ...
1
vote
0answers
413 views

Importing GPS coordinates correctly

I am importing a gsx set of waypoints with lat/lon taken in degrees, minutes, and thousandths of a minute. When they are added to my project, the waypoints are not showing up correctly - the ...
2
votes
1answer
854 views

What happened to Live GPS Tracking in 1.8.0-Lisboa?

Dang, I was just getting used to Live GPS Tracking in 1.7.4-Wroclaw. I downloaded the new version 1.8.0-Lisboa on another computer. The Live GPS Tracking thing was in the View pull-down menu in ...
7
votes
3answers
611 views

GPS integration with multiple waypoint routes

I'm building a system that needs to get the output of a route optimizer into the hands of a driver who intends to make deliveries on that route. Whilst I can supply this to the driver as a printed ...
4
votes
3answers
365 views

API to suggest nearby streets

For an app I'm developing, I want to use the phone's GPS to locate it. I then want it to list streets that are nearby. The customer might be in his back garden for example, and this may be closer to ...
3
votes
0answers
693 views

How to handle real time GPS data with ArcGIS Javascript API? [closed]

I'm developing a web app using Arcgis Server 9.3.1 and Javascript API I have a database with gps data from several vehicles and I need to display each vehicle real position in a map. I display this ...
8
votes
1answer
611 views

Cleaning GPS track data

I have data captured with a GPS tracking unit. Some track have bad/cold starts and the only way to determine the track quality is by using the altitude. Unfortunately I don't have the raw GPS data and ...
3
votes
1answer
76 views

set wrong GPS unit in “degree” and want to change to “meter” in GIS while editing

I want to edit the GPS result in ArcGIS, but I found that there is a problem. I set the wrong unit while I used the GPS outside , and the unit is "degree". Although the coordinate system is correct, I ...
1
vote
2answers
2k views

How do I open a shapefile in QGIS for upload to Garmin GPSmap 62?

I now have a polygon and have succesfully raised 25 random sample points and saved as a shape file. I have checked that GPS utility and the shape file are set at 27700 BNG but when I try and open the ...
0
votes
2answers
2k views

Converting GeoExplorer gps data points

I have been given what I'm told are differential corrected gps points (DGPS) and asked to convert them to something usable in current GIS (e.g. Arcgis, Qgis). They have names like R081320a.cor, ...
1
vote
0answers
264 views

how to correct the coordinate of points [closed]

I have some a layer which contains some points. The coordinate of the points should be GPS points. However, the coordinate of these points are not correct. What should I do? I am using QGIS. If I ...
3
votes
2answers
195 views

What is the minimal data necessary to reconstruct GPS location?

Imagine that a minimal GPS device is attached to a moving object (animal, shipping container, geocache object, etc). Every few months, data from the device is downloaded for post-processing. What ...
3
votes
1answer
173 views

is the GPS network free or available for any device?

I have a question (I'm really sorry if is kind of dumb question). But if I have a device with GPS (smarthphone,pda,pocket pc, etc) Does the device need any additional service to enable GPS data? I ...
3
votes
6answers
7k views

Sending GPS Location to server

Is it possible to send my current location on iPhone or Android to the server so that others can view my current location?
5
votes
2answers
880 views

Garmin etrex 10 and QGIS

I want to know if anyone has been able to download data from a etrex 10/20/30 directly from Qgis. The usb protocol decsribe in a recent post does not do the trick. GpsBabel documentation states that ...
2
votes
1answer
534 views

Snap Polygon vertices to Point features

I have a set of polygons drawn using an inaccurate GPS PDA. these polygons are sharing nodes. after post-processing GPS data to get accurate coordinates i have a set of all the nodes, then i have to ...
11
votes
1answer
691 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 ...
1
vote
3answers
244 views

How to upload and download to gps

Do you have a step by step guide on how to upload/download points/wayponts and polylines/routes from a gps? Regards Christo
3
votes
1answer
224 views

How to overlay map onto a corner of an image, using that image's GPS exif data?

I have several hundred JPG images taken during a time lapse of a drive, with each image containing embedded GPS information. Is there an OS X friendly workflow that can allow me to: create a ...
13
votes
3answers
4k 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 ...
3
votes
1answer
378 views

GPS problem in QGIS

I have a very strange problem that I cannot understand. I am trying to put together a demo-laptop with QGIS and gps. On other computers I have it working as expected, but on this particular box ...
19
votes
2answers
426 views

Precision when working with spatial data in GIS

Is there a basic or introductory study that examines and compares the precision of spatial data when working with varying precison of the data input, like having 1, 2, ... decimal places? with the ...
2
votes
1answer
3k views

How do I calculate a xyz-position of a gps-position relative to an other gps-position?

I have two gps-positions (lon, lat, alt) and want to get the position of one relative to the other one. (in meters, as x, y, z) How do I do that? Thanks in advance. Edit: The locations have a ...
11
votes
3answers
3k views

Bluetooth GPS to Smart Phone

Has anyone had any luck intergrating a GPS unit with your Smartphone? Looking to gain sub 5m accuracy. Ideally would like the phone to just use the better gps reciever when it is connected. This ...
4
votes
1answer
261 views

Proper work flow to move manholes and pipes to surveyed location

I would like to know how to accomplish the following task using QGIS. I have an existing point shapefile representing sanitary sewer manholes and an existing polyline shapefile representing sanitary ...
1
vote
1answer
163 views

Mobile location determination

I was wondering how Google Maps on my Android phone can locate me with a good accuracy when my GPS is disabled. At first I though it was with the cell tower but I'm not sure it can achieve this ...
22
votes
7answers
7k 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 ...
2
votes
2answers
567 views

How to convert Garmin Waypoints to Google Mercator?

I have georef some topocards with QGIS and the Google Hybrid Layer. So, this cards are connected with the Google Mercator System. Now I have some waypoints taken with Garmin GPSmap62 (in WGS84). ...
1
vote
0answers
317 views

Holux GPS logger .itm fileformat

I'm looking for a spec sheet or a library to open and decompress .itm files from the Holux GPS logger. Has anyone worked with the proprietary .itm format already and can provide me with some usefull ...
3
votes
2answers
418 views

How to get the layers of my project to show while tracking with GPS?

I've been using/testing several versions of various GIS software and run into occasional issues. Right now, my biggest with QGIS is with GPS connection/downloading from/tracking. These are all ...
33
votes
12answers
23k views

Tablet or smart phone GPS vs “real” GPS

I've been reading a lot today about android and iphone devices being used for spatial data collection in the field and it sure seems to be that single purpose devices such as the extremely popular ...
11
votes
2answers
1k views

Why is getting a GPS fix so slow?

I understand the basic concepts of GPS positioning system and the use of trilateration but I don't understand why it takes so much time to get a fix. On commercial GPS like TomTom it usually takes ...
3
votes
3answers
887 views

GPS device taking pictures and saving heading + HDOP?

I'm looking for a device that can do all of the following: Take picture Save lat-long GPS position + heading (angle to North) of picture [so need tilt-compensated 3D compass], in exif or other ...
0
votes
0answers
37 views

Calculating ECEF X, Y, and Z velocities between 2 points on Earth [duplicate]

Possible Duplicate: How do I calculate ECEF X,Y,Z velocities for GPS if I have no satellites This is my third attempt at explaining what I'm trying to do. If I have two ECEF X, Y, Z ...