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

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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 ...
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2answers
1k views

Locations of Geodetic Survey Benchmarks

Does anyone know where I can find a list of geodetic benchmark locations for Ontario? (If a list even exists that is...) Thanks
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1answer
487 views

Can an htm file be imported into Trimble's Data Dictionary Editor?

We've received several data dictionary files from other entities and they all are in *.htm format. We were hoping to not reinvent the wheel, as these are massive data dictionaries, so does anyone know ...
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Do's and Don'ts for GPS Localization

We have recently purchased some new GPS survey gear (ProMark 500) and we have set up a localization around the town using some of the known survey marks. While I'm pretty confident that I have got it ...
16
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3answers
528 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 ...
23
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6answers
803 views

How to cope with the newly discovered GPS bug? [closed]

Today the New York Times broke the news that after the Clinton Administration turned off Selective Availability in the GPS system, a bug had been introduced into the GPS satellite software itself, ...
5
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1answer
338 views

PLT track in PostGIS

What are the best practices for importing and aggregating tracks (in my case in 'plt' format) in a PostGIS table, grouped by user. Are there any tools/db models/tutorials available?
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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 ...
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5answers
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Does an earthquake affect GPS?

There are news reports saying that the Sendai earthquake a couple days ago has shifted the earth on its axis and moved the island 8 feet. Last year, there were similar reports with the earthquake in ...
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Free MobileGIS like ArcPAD

I'm looking for open-source program like ArcPAD. I have read all questions and answers, but i find nothing. I need the program for PDA (Dell axim x51v + GPS modul) and I want mapping points (trees or ...
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8answers
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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... RhinoSpect ...
5
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2answers
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postprocessing GPS coordinates with RINEX data to improve precision?

Im doing some mapping for OSM in my region and I am curious if the precision of tracks from a GPS Receiver can be improved if they are post processed with RINEX data. The tracking is done with a ...
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10answers
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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 ...
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4answers
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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 ...
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4answers
1k views

How can I get my GPS track data into a graphics program?

I'm using a Garmin Edge 705 bike GPS/computer unit, which produces .gpx files. I can use the standard software it comes with to plot on Google Maps etc, but I'd like to be able to output just a vector ...
25
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7answers
2k 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 ...
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3answers
283 views

Differentiating a building from a road on a map?

This question was originally asked here by Steven and I felt the question was better asked here. Steven would also like to know the sources Google buys it maps from. I remember seeing a post about it ...
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3answers
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GPS Tracking by SMS

I have a GPS Tracker which sends the GPRMC string of the NMEA 0183 protocol, at fixed periodicity, to a predefined number as SMS. I am looking for a software which can port these incoming SMS to a COM ...
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6answers
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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 ...
4
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5answers
359 views

How do I find software for my GPS?

I recently unearthed a GPS unit I purchased a few years. It's a Garmin GPSmap 60 (picture) and has a usb port on it. Is there a way that I can link it to my mac? I do have windows installed also, and ...
11
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4answers
731 views

GPS to map workflow, for non-GIS folk

What applications and workflow(s) do you use for gathering, displaying and storing GPS data, with your centralised corporate data, for people who are not GIS folk? We're in the process of ...
8
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1answer
124 views

Is there a geodetic benchmark that is fixed with respect to plate tectonics?

I see that NGS benchmarks are used to monitor the movement of geologic plates. Is one of the benchmarks assumed to be in a fixed location, with movements of all other benchmarks measured with respect ...
3
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1answer
222 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 ...
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3answers
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What is the easiest way to measure a polyline using either QGIS or ArcGIS

I've collected a bunch of GPS polylines (WGS84). What is the easiest way to measure the length of these lines in KM?
12
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3answers
366 views

Software for analyzing GPS tracklogs to extract human-readable placenames

I have a pile of GPX-formatted tracklogs for many countries where I've travelled over the years (the GPS-device has been continuously on and recording for most of the trips). I would now like to ...
6
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2answers
544 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. ...
3
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1answer
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show position on google map/earth, from gps data, using google API

For those that have used google's API for mapping (google maps/earth), I would like to know if is it possible to develop an application to receive NMEA data from a gps receiver, extract position, and ...
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1answer
242 views

Converting GPS heights to AHD heights

I was wondering if there is a way to convert heights that are logged from a normal bluetooth GPS to AHD heights.
3
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6answers
838 views

Advantages of a GPS enabled PDA for field asset management

I'm having some trouble trying to convince some people of the advantages of having a entry level GPS enabled PDA for asset management. I've been asked to look into GPS enabled cameras, I've since ...
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3answers
231 views

Length of forms in ArcPad10

I'm trying to create a survey with about 250 questions in ArcPad 10. Normally you would expect that a form you created in any application will be able to scroll in PDA if it is too long. But the ...
3
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2answers
620 views

in seach of gps tracking (web) service to use with rails web app

hey out there GISers, i am looking for a gps tracking service i can hook gps devices into and request their infos via a ruby on rails webapp. does anybody know some? any help is appreciated! thanks, ...
9
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5answers
923 views

How can I find positions on my land?

I have about 2 acres of land, wooded and brushy. There was a survey and the corners have rebar. I am working on a site plan for house construction. I have two related problems: Finding a spot on ...
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1answer
908 views

How to convert from ITM ref to GPS ref ?

How can I convert from ITM ref (Israel new map) to GPS ref and from GPS ref to ITM ref? I need any C# sample code or formula for this. For example: 32.086156,34.769239 = 178364,665948 Or : ...
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How can I plot GPS coordinates on Google Map

What is the best way to plot GPS coordinates on a Google Map? Are there any tools that can do that (written in python specifically)?
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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 ...
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4answers
129 views

Where to license non-automotive POIs for France, Spain and Portugal?

qualified POIs are needed for a commercial project - should cover broad out-of-car usecases (not needed: parking, gas stations). Could be commercially licensable data or derived from national geodata ...
5
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1answer
892 views

Calculating absolute precision confidence number from Dilution of Precision indicators from GPS receiver

End-user GPS receivers typically show an absolute confidence indication, such as Within 25 Metres, for the calculated position. I am parsing NMEA data from a GPS unit and wan't to calculate a similar ...
18
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6answers
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Is GPS more accurate on specific hours of the day?

I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day. If this is true, how can I get the information on when GPS is more or less accurate at my ...
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4answers
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What data is sent from GPS satellites to receivers?

I know more or less how the GPS system works. But I would like to understand it in more details. Exactly what data is sent from a GPS satellite to a GPS receiver? I think there is multiple types of ...
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3answers
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What are the major differences between GPS, GLONASS and Galileo?

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