Frequently Asked Questions about GPS Visualizer

This document is mostly about GPS files, the map-making process, and the drawing files that are output from GPS Visualizer. For information on how to format plain-text input files (the most flexible kind of input), please have a look at the Tutorials section.

General questions

Mapping issues

GPS data files


Google Maps



General questions[Return to top]
Q. Do you take suggestions for new/enhanced features?

Yes, of course. However, since GPS Visualizer is not its owner's full-time job, it doesn't always get priority. So, regardless of their usefulness, "easy" suggestions (like fixing the text-import routines to work with more data files) get implemented much quicker than long, involved ones (like figuring out how to incorporate maps from the UK Ordnance Survey) that would require writing or re-writing big chunks of programming code.

Of course, thanks are due to the kind souls who have sent donations over the years.

Q. I got the output to look just right, and now I want to save those settings for the next time I make a map. Is that possible?

After you draw a map, you should see a link that says "Return to the GPSV map form," or "Return to the input form," or something along those lines. It will either be to the right of your map or below the link to your output file. Click on that link and then bookmark it — add it to your Favorites — or whatever your Web browser calls the process of saving a URL for later. The resulting bookmark will take you to a form with all your favorite options pre-selected. Note that all the options are sitting right there in the URL of the form (for example, the width of the map would be indicated by "&width=800"), so you can also adjust it if need be.

Q. What are GPS Visualizer's system requirements?

To create and view JPEG and PNG images, you don't need anything special — any Web browser will work. GPS Visualizer is platform-independent.

For Google Maps, any modern browser should work just fine.

To use Google Earth files (.kml/.kmz), you'll need Google Earth, which is a free download for either Mac OS or Windows.

To view SVG maps and profiles, most Web browsers will work.

Q. Is GPS Visualizer available as a standalone application that I can download and use off-line?

No. But it's really not all that useful without background maps, Google Earth, or the Google Maps API, and you'd need to be on-line to access those anyway.

If you need a conversion utility that works without an Internet connection, check out GPSBabel (cross-platform) or Alan Murphy's excellent GPS Utility (for Windows).

Mapping issues[Return to top]
Q. I want to map a collection of individual points, but GPS Visualizer keeps connecting the points with a line as if they were a "track."

When you upload plain-text data, GPS Visualizer tries to guess what kind of data it is. If there is a "type" column filled with T's or W's (indicating trackpoints or waypoints), there will be no question. If there is a "name" column, the default behavior will be to read your file as discrete points (waypoints). In the absence of a "name" column, the default will be a continuous line (trackpoints).

So, if your waypoints are erroneously read as trackpoints (or vice versa), there are a few different things you can do to fix it:

  1. In the input form, set the "Force plain text" drop-down menu to the appropriate option.
  2. If you want waypoints, add a "name" field to your data; you probably want to define names anyway, as they make for a more useful map. (if you have names in a different field, like "Site ID" or "Company," just rename it that field to "name," or use the "synthesize names" feature in the advanced options.)
  3. Add a "type" column and fill it with T or W as appropriate.

For more information, see the plain-text data tutorials.

Q. I uploaded both tracks and waypoints, but some of my waypoints are not appearing on the map.

By default, GPS Visualizer only shows those points that are within or very close to the boundaries of your track data. This way, you can upload a file with points from all over the world, but you won't get a map covering the whole world (or however much territory is covered by your waypoint collection). But if you do need to plot all of your points on your map, just change the "Show waypoints" menu to "All" — in some map forms, this setting may be in the "advanced" waypoint options. You can also try leaving it on "In bounds of track plus padding" and increasing the "padding."

Q. I tried to map some waypoints where one of the points was a long way from the others, and the far-flung point is not showing up.
Q. My file contains one or two waypoints that are far away from my other points, and I don't want to plot the "outliers."

You may need to adjust the "discard outliers" setting, under "Advanced waypoint options."

If you want all points to be plotted, regardless of how far away they are, set it to "No, show all points" (if you are also uploading tracks, you will also need to verify that the "Show waypoints" setting is on "All").

If you want fewer waypoints to be plotted — for instance, if you have a large cluster of points near your home and you only want to show those — set it to discard points whose "critical Z-score" is above a certain level. (Z is a statistcal measure of the number of standard deviations from the average.)

Q. My map is too skinny; how can I make it closer to square?

The dimensions of your map are determined by your data. If you plot a track along a road that goes directly east-west, you'll get a map that is much wider than it is tall. If you're making a Google Map, you can manually set the height and/or width, and you can also set the "initial zoom level" to -1 if you want the map to cover more area. For a JPEG, PNG, or SVG map, increase the "margin" setting or manually set the height and/or width.

Q. Why are all my points showing up in China (or Mongolia, or off the coast of Africa)?

If you were expecting a map of somewhere in North America but you got Central Asia instead, that means your points were not properly marked as being in the Western Hemisphere. Longitudes greater than zero (positive numbers) are interpreted as being east of 0° unless they are marked with a "W": the coordinates "40.7,-74.0" (or "N40.7,W74.0") point to New York City, but "40.7,74.0" will take you to a lonely ridge in Kyrgyzstan. Similarly, latitudes are assumed to be in the Northern Hemisphere unless they are negative or include an "S".

If you open your map and see nothing but ocean, then zoom out and discover that you're looking at the Atlantic Ocean off the coast of West Africa, that probably means your latitudes and longitudes somehow got interpreted as zeroes, and you're looking at the intersection of the Equator and the Prime Meridian.

You might also find that some or all of your points are in a perfectly straight line along the Equator or the Prime Meridian; in that case, either your latitudes or your longitudes (but not both) got lost. Usually this happens because data fields/columns got misaligned; check your commas.

Q. I uploaded a KML file from the "Google Maps Engine," and none of its markers are showing up.

The files generated by Google's "Maps Engine" often don't have any latitudes or longitudes in them — only street addresses. When such a file is opened, the application that opened it needs to contact Google and ask for the coordinates of those addresses. GPS Visualizer's server can't make those geocoding requests for you, because Google places a quota on how many addresses can be processed daily by a single IP address, and GPS Visualizer makes thousands of maps per day.

The solution is simple: open your KML file in Google Earth, then re-save it as KML or KMZ from Google Earth. The resulting file will have latitudes and longitudes in it, so other programs (like GPS Visualizer) will be able to read it with no problems.

GPS data files[Return to top]
Q. My data is in tab-delimited or comma-separated text files. In which units should the coordinates, elevation and speed be represented?

Plain-text coordinates should ideally be decimal; this means south and west are negative, north and east are positive, and there is no such thing as minutes and seconds. If you do submit degrees and minutes, or degrees, minutes, and seconds, GPS Visualizer will try to figure it out, but there are no guarantees. Just make sure that latitude and longitude are each represented by a single column; you can't have multiple columns for degrees, minutes, and seconds.

Elevation is interpreted as meters, and speed is interpreted as kilometers per hour, unless the header row indicates otherwise — for example, you could name the speed column "speed (mph)", and GPS Visualizer should understand what you mean. (In GPX files, however, please note that speed should be in meters per second.)

See the Waypoints Tutorial for more information.

Q. Can I use UTM coordinates? (Northing, Easting, & Zone)

You can use UTM coordinates in plain-text files with a header, as long as the columns containing the UTM coordinates are properly labeled (UTM Zone, UTM Easting, & UTM Northing).

Q. Are the names of my data files important?

Yes. For the most part, GPS Visualizer determines what kind of files you've uploaded based on the names of the files. Here's a list of most of the filename endings that GPS Visualizer recognizes:

.abxMagellan Roadmate address book
.an1DeLorme drawing file
.anrDeLorme Street Atlas route
.axeMicrosoft Autoroute file
.binBinary log file (from various sources, including Furuno, Emtac Trine, Magellan Roadmate, Maka/Marbella)
.btkBushnell Backtrack D-Tour tracklogs
.cpoEnerGymPro tracklog
.crsGarmin Training Centre "course" file (XML)
.csvComma-separated text (including Timex Trainer, Furuno NavNet 3D, et al.)
.ctcCoutraci binary tracklog
.datAPIC binary file, GiSTEQ PhotoTrackr, Northstar waypoints, Evermore, et al.
.flightlogSkyDemon flight logs
.fplFliteStar XML files
.fshRaymarine archives
.gdbGarmin Mapsource
.gepBTwin SatCount
.ghdGeonaute KeyMaze logs
.gpbDell Axim binary file
.gpiGarmin "Points of Interest" database
.gplDeLorme GPL file, Blackerry GPSLogger tracklog, or SkyRC GpsLogger tracklog
.gpmGPSMeter PDA file
.gpsedGPSed (Blackberry) tracklog
.gpxGPX (GPS eXchange format): the most common and interchangeable of all GPS file formats
.gsdGlobalsat plain-text tracklog
.gsrUSGlobalSat binary tracklog (as from DG-200)
.gstGeosetter tracklog
.gt7Outdoor Navigator Pro tracklog
.gtkBushnell Backtrack D-Tour waypoints
.hstGarmin Training Center history file (XML)
.igcIGC log file (from sailplanes)
.kml/.kmzGoogle Earth KML
.lmxNokia "Landmarks" file XML waypoints (not Terrabyte/TopoGrafix)
.logVarious tracklog formats (Xplova, Jeppesen, QinetiQ, Canmore, TrueCam, Sygic, et al.)
.ltbPioneer AVIC files
.mpsGarmin Mapsource
.mrkMaptech Terrain Navigator
.ngtNoniGPSPlot track logs
.nmea/.nmeRaw NMEA sentences
.ns1NetStumbler binary log file
.olgOakGPS tracklog
.pdbPalm OS databases from Cetus GPS, Pathaway, or cotoGPS
.pcxPCX5 tracklog
.pglTomTom text log file (modified NMEA)
.pltOziExplorer tracks
.pspPSP290 tracklog
.ptsPrecision Mapping Streets and Traveler (UnderTow Software)
.pvtMagellan Maestro tracklogs
.rdnFichiers de IGN Rando (français)
.rt3Transas XML files
.rteOziExplorer routes
.sbn/.sbpLocosys Genie tracklog
.sdfSuunto SDF file
.smtVito Navigator II tracks
.srwSeaClear nautical waypoints
.stkSeamaster Pro files
.tcxGarmin Training Center history file (XML)
.tesWintec WBT-xxx binary tracklog
.trkTracklog: PCX, CompeGPS, GPS Tuner, Mapsend, Maptech, iGO, iGO Primo, Fugawi, Orion SkyTrack, TrackMaster 2000, Magellan NMEA, et al.
.trlBushnell, TrackLogs digital mapping, et al.
.tr7/.ppgMapAsia MapKing track log
.txfMaptech text export file
.txtTab-delimited text
.ubxU-Blox binary track file
.usrLowrance USR file
.vccVelocitek Control Center XML file
.vrtpViewRanger tracklog
.wptWaypoints: PCX, OziExplorer, Fugawi, CompeGPS, Mapsend, Magellan NMEA, probably others; Tracklogs: Chrysler MyGig
.xls/.xlsxMicrosoft Excel spreadsheet
.xmlGarmin Forerunner Logbook, Sportek, CycleOps, et al.
.xolSwissTopo's Swiss Map Mobile
everything elseInterpreted as tab- or comma-delimited text in the absence of other clues

Also, be aware that the first part of a file's name (before the suffix) will be used as the name of the track — that is, if it's a file format that doesn't include a specific place for track names.

Q. I have a Garmin Forerunner, and I don't want my entire Logbook to be mapped; how can I only map some of the tracks?

Split the Logbook XML file into individual runs and upload them separately. You could do it by hand using a text editor, but it's a lot easier to use GPS Visualizer's Logbook Splitter utility.

Google Maps[Return to top]
Q. How can I print my Google Map or save it as a JPEG?

Good question. It seems that printing maps created using the Google Maps API is unreliable at best. Every browser seems to behave a little bit differently, so any "tricks" to make it work in, say, Firefox, might cause everything to blow up in Internet Explorer.

The safest bet is to simply take a screen shot and print that. Here are some tips on doing that:

Firefox & Chrome (any platform): install a browser extension/add-on/plugin that can capture the entire contents of a browser window — even the parts that are currently off-screen. (Note: if you want a really large map, be sure not to select "full-screen mode" when you make your map; in full-screen mode, the map is exactly as big as your browser window and no larger.) For Firefox, Screengrab! does the job in a quick, no-frills way. For both Firefox and Chrome, Nimbus Screen Capture works well and lets you edit/annotate the image before saving it.

Mac OS X: The keystroke Command-Shift-3 will save a picture of your entire screen to your Desktop. You can open that picture in a graphics program or just print it as-is using a program like Preview. Perhaps more useful is Command-Shift-4, which changes your cursor into a crosshair so that you can select the area of the screen that gets saved (hit the space bar to select an entire window). Or, to save part of the screen to the Clipboard — from whence you can paste the captured area into another program — try Command-Shift-Control-4. See this Apple support document for even more options.

Windows: Hitting the Print Screen key copies the contents of the entire screen to the clipboard, and from there you can paste it into a graphics program — even MS Word or "Paint," if you don't have anything fancier. Alt-Print Screen copies only the frontmost window. Or, for far more flexibility and options, try IrfanView, a powerful freeware utility. (Click here for more info on Windows screen captures.)

Note that there may be copyright issues involved with using Google's street maps or satellite imagery. If that's a concern — because your map may be published commercially — use one of the alternative backgrounds, like topo maps, NAIP aerials, OpenAerials from MapQuest, or OpenStreetMap/OpenCycleMap.

Q. How can I save my Google Map to my desktop or my own Web site?

(First of all, if you just need an image rather than an interactive map, see above under "How can I print my Google Map or save it as a JPEG?")

When you tell your Web browser to "Save" your map, do not choose "Save all files" or "Save Web archive" or "Web page, complete" or "MHTML" or ".mht" or anything else that suggests that your browser will create a collection of local graphics and JavaScript files along with the HTML file itself. You want to save the HTML source only.

If you just need a copy of your map for your own reference, you should be able to open the local file in a Web browser. If you want to share it with others, you'll need to put it online somewhere. If you don't have your own Web site, you can upload your map to a free account on Google Sites, GitHub, or something similar.

Important note about "https":
Because URLs on, Google Drive, Google Sites, and GitHub — among others — begin with https:// instead of http://, GPS Visualizer's scripts may cause a "security warning" in some Web browsers, which may cause the map to appear blank. So if your site is hosted on a secure URL, you should edit your map to use the following secure URL for GPS Visualizer's Google Maps functions: (search for "" and replace it with "").

Q. What's the best way to incorporate the map into my Web page? Can I put multiple maps on the same page?

By far the easiest solution is to put the map in an "inline frame" using the <IFRAME> tag. This creates a "window" in your page into which you can load another file (more info about IFRAMEs). The advantage of doing this is that the DIVs and margins and styles and whatnot will be completely isolated from the rest of the structure of your page. (The only disadvantage, and one which would only affect "power users," is that if you want to create links outside the frame that interact with the map inside the frame — for instance, a list of waypoints, or a control that will re-center the map — it's a little bit more difficult.)

Another advantage to IFRAMEs (as opposed to cutting and pasting bits of HTML into your page) is that you can place as many of them on your page as you want; because they are isolated from each other, there shouldn't be any conflicts even if all the maps have identically named parts.

Here's a sample <IFRAME> tag:

<iframe src="my_map.html" width="700" height="500" marginwidth="0" marginheight="0" scrolling="no" frameborder="0"></iframe>

Please note that while it is technically possible to simply create an IFRAME that points to your map's initial URL on, that is only a very temporary solution, as older maps are deleted from the server every night. Instead, you should save a copy of the map to your own server, as described above.

Q. Which background maps are available in a Google Map created by GPS Visualizer?

There are many choices. For the complete and current list, click here.

Q. How can I exclude certain background map choices (or only include a small list of choices) in the map type control on a Google Map?

Edit your map's HTML source and look for gv_options.map_type_control.excluded; edit the list in square brackets to include whichever maps you want to hide; or, change it to .included and put in the list that you want to be available.

For full details, click here.

Q. Can I upgrade an older GPS Visualizer map to use Google Maps API v3?

Yes. In fact, if you don't upgrade, it may stop working at any moment, because Google has pulled the plug on the v2 code. For detailed instructions on how to update an older map, read GPS Visualizer's Google Maps v2 to v3 migration guide.

SVGs, JPEGs & PNGs[Return to top]
Q. Which output format should I use: SVG, JPEG, or PNG?

If you're just going to look at your map, SVGs are really not much different from "flat" pixel-based image formats, and you may as well make a JPEG or PNG. (The only difference between JPEG & PNG files is that PNGs are larger, uncompressed files — PNGs look a little bit cleaner but can take longer to load. The actual drawing is the same.)

If you need to import your data into a vector graphics program like Adobe Illustrator, an SVG map can be very very useful — and GPS Visualizer may be the only free utility out there that can turn any GPS data into editable vectors.

Q. Where do the backgrounds in the SVG/JPEG/PNG maps come from?

The maps are NOT stored on GPS Visualizer's server; they come from various sources on the Web. The list of backgrounds changes from time to time as new data sources become available or are removed from public circulation. If you know of any other sites which might work, please let me know.

Q. I selected a background map, but nothing is showing up.
A. There are a few likely explanations:
  • It hasn't shown up yet. Be patient. Some of the map choices take a while to show up.
  • The map server is down. Sometimes the servers that produce these maps become unavailable for a few minutes, hours, or days.
  • You're out of range. If you try to display a U.S.-only map behind a track that was recorded in Sweden, it just isn't going to work.
  • You're in the boondocks. If you're trying to plot a 5-kilometer hike in the Australian Outback, your background might be blank because there's simply nothing to draw!
  • You're asking for a JPEG/PNG map that's larger than the map server is willing to give. For some servers, the upper limit is 1024 pixels, for others it's 2000 pixels.
Q. I saved an SVG and tried to open it in Adobe Illustrator, but the background map isn't showing up. What can I do?

When you first create your SVG, be sure to enable to option labeled "Embed map in SVG." Illustrator isn't able to display linked graphics on remote Web sites, but it can handle embedded JPEGs.

Miscellaneous questions[Return to top]
Q. Which geodetic datum does GPS Visualizer use?

GPS Visualizer uses WGS84 and assumes any input is also in WGS84. (Note that NAD83 coordinates are almost identical to WGS84; NAD27, however, may be up to 100 meters off.)

Q. What's the difference between "markers" and "waypoints"?

There's really no difference at all. In the GPS world, discrete points are usually referred to as waypoints, but when you put them on a map, they're identified by markers (a.k.a. icons or symbols). In GPS Visualizer's documentation and code, you might see both terms used.

Q. What's the difference between "heading" and "course"?

Technically, "heading" is the direction your ship (or other vehicle) is pointing, whereas "course" is the direction you're moving. GPS Visualizer's documentation and input forms use the two words synonymously, and they are referring only to the direction of movement (course), not one's orientation in space. "Heading" is used simply because more people are familiar with the term.

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