GPS Visualizer

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

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 Google Maps tiles into SVGs or PNGs) 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.

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.

What are GPS Visualizer's system requirements?

GPS Visualizer is a platform-independent Web site, not a downloadable app. To create and view Leaflet and Google Maps, or JPEG, PNG, or SVG images, you don't need anything special — any Web browser will work.

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

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 or Leaflet 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).

Can I publish a GPS Visualizer map or profile in a book or article, or on a Web site?

Absolutely! The only caveat is that some of the background maps (e.g., Google, ThunderForest, ArcGIS) may have permission issues of their own, if you're planning to produce something for a non-Web medium. USGS/USFS tiles and most OpenStreetMap-based layers are OK to use, but proper attribution is still required. In a Google/Leaflet map, there's always a link with information about the current background in the bottom right corner of the map; be sure to click there for more information.

For elevation profiles, there are no copyright/permission issues at all.

(Of course, it would be nice if you credited GPS Visualizer for the mapping assistance, with a live link if it's an online publication.)

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."
I want to create a track, but GPS Visualizer keeps drawing the data as unconnected points.

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.")
  3. Add a "type" column and fill it with T or W as appropriate.

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

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

If you have the "Show waypoints" option set to "In bounds of tracks," 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, make sure "Show waypoints" is set to to "All" — in some map forms, this setting may be in the "advanced" waypoint options. You can also try "In bounds of track plus padding" and increasing the "padding."

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.
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.)

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 Leaflet/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.

Why are all my points showing up in China (or Kyrgyzstan, 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.

Why are all my tracks gray (or white, or red), even though I chose another color in the input form?

Your input file probably has track colors already defined. This is common in KML files, and in GPX files that came from a Garmin device. (If you open your .gpx file in a text editor, you might see "gpxx:DisplayColor" tags.)

You can tell GPS Visualizer to ignore these colors by opening the advanced track options and setting "Preserve track styles in input files" to "No." There is a similar setting for waypoint styles.

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.

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.

In which time zone are the time stamps of processed GPS data?

Good question! Time is a very tricky variable to work with. Daylight Saving Time (a.k.a. Summer Time) makes it even trickier. If you want GPS Visualizer's output to be in a particular time zone, you can use the time_offset parameter (in the "advanced options") to adjust the times, but it may take some trial-and-error to get it right.

GPX files: By default, the GPX file format records timestamps in UTC (GMT), but does not store information about the local time zone. If you convert a GPX file with GPS Visualizer, the output will be in unconverted UTC.

Plain-text files: GPS Visualizer will generally pass plain-text timestamps to the output without converting them. If your input says "2000-01-02 03:04:05", that's what you'll find in the output. (If the output is GPX, the time will be labeled as "Z", meaning UTC.)

Binary files: Many GPS devices spit out proprietary binary files, and these files may or may not include time zone. GPS Visualizer will try its best to convert binary timestamps to UTC, but the results are not guaranteed. You may need to adjust the time offset parameter.

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

You can upload 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). Note that a "Zone" or "UTM Zone" column is required.

If you want UTM coordinates in your output, open the advanced options in the conversion form, and look for the "Output UTM coordinates" option.

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. Below is a list of most of the filename endings that GPS Visualizer recognizes (click here to free it from its scrolling box):

.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.

I have a large GPX file or Garmin Logbook/TCX file, and I don't want my entire file to be mapped; how can I only map some of the tracks?

Split the GPX or Logbook 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 GPX/Logbook Splitter utility.

How can I change an older Google Map to a Leaflet map so I don't have to deal with an API key?

The Google-to-Leaflet conversion page contains instructions, as well as a simple tool to alter your maps for you.

How can I print my Leaflet/Google Map or save it as a JPEG/PNG?

Good question. It seems that printing maps created using a mapping API is unreliable and inconsistent. 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 Chrome.

The safest bet is probably 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 Chrome, 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 Microsoft 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.

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, or OpenStreetMap.

How can I save my Leaflet/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 Leaflet/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 000webhost (recommended), GitHub, or something similar.

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.

Which background maps are available in a Leaflet/Google Map created by GPS Visualizer?

There are many choices. For the complete and current lists, click on one of the following links: Google, Leaflet.

Can I include custom background tile layers in my map?

Yes. Click here for details and a quick form for inserting a URL template.

How can I exclude certain background map choices (or only include a small list of choices) in the map type control on a Leaflet/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. You can see more details here.

I have a KML/KMZ file full of addresses; how can I get their coordinates?

When a Google Earth placemark's location is set via a street address instead of coordinates, there are often no coordinates in the KML/KMZ file, so if you try to convert these points, it doesn't work because GPS Visualizer's server does not perform geocoding.

While it is possible to solve this problem using GPS Visualizer's Batch Geocoder, there's a much easier way: Simply open the file in Google Earth and then re-save its contents as a new KML file. But before saving it, you have to WAIT while Google Earth looks up all the locations and figures out what their coordinates are. Once new icons stop appearing on the map in Google Earth, it should be safe to save it.

(Note that for some reason, Google Earth sometimes draws a rectangle around each one of the geolocated addresses. To remove these shapes, you can enable the "Remove all tracks" option in GPS Visualizer's converter.


How can I animate my tracks in Google Earth?

Google Earth has two different ways of drawing tracks/lines on a map: "Tracks" (the KML <gx:Track> tag) and "Line Strings" (the KML <LineString> tag).

With KML Tracks, each point in the track can have its own timestamp, and Google Earth has the ability to animate a track based on those timestamps. GPS Visualizer does not (yet) have the ability to create KML Tracks, but if you convert your data to a GPX file with timestamps, you can open that GPX file directly in Google Earth and use the built-in track animation.

With KML Line Strings, an entire track is treated as a single drawing element, so the individual points/segments do not have their own times. However, you can use GPS Visualizer to create a different kind of animation: if you enable the "Add time stamps" and "Draw trackpoints as waypoints" options in the Google Earth input form, you can animate the waypoints. The track will always be visible in the background, and the waypoints will travel along it like a caterpillar on a roller coaster.

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.

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.

I selected a background for my SVG map, but nothing is showing up.
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.
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.

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.)

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.

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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