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Upload your files

Applies to: all formats

Notes about uploaded files:

• Latitudes and longitudes must be in decimal format, not UTM "northing" and "easting." Negative numbers are west and south, Positive numbers are east and north.
• You can mix and match file types; it's not a problem if, for example, your waypoints came from Cetus but your tracks are in GPX format.
• Most file types are detected by their filename suffix, so make sure their names end in ".gpx", ".pdb", ".csv", ".wpt", ".plt", ".igc", ".xml", etc.
• If you upload multiple track files, they will be plotted as separate paths in the same graphic.
• Tab- or comma-delimited text tracklogs (except application-specific files) must have a header row that includes the names of the fields (most importantly, "latitude" and "longitude"), so that GPS Visualizer knows which columns the important information is in. Comma-separated files must have names that end in ".csv".
• If you want a plain text file to be interpreted as a collection of waypoints rather than a track, the first field must be named "type". Then, each record in that column should begin with "W" under the "type" field. To force a file to be interpreted as tracks, do the same thing but put "T" in the first field. You can even mix and match trackpoints and waypoints in the same file, as long as you label them as such.
• If you're using Internet Explorer 5 on a Mac, your GPX files might not upload properly if their file type is not set to TEXT. Don't ask me why; but click here or here for a useful file-type-changing utility. Or use Mozilla.

Enter/paste your data

Applies to: all formats

As an alternative to uploading a data file, you can simply paste comma-separated data into a text box. You would typically do this when your data didn't come from a GPS device but was constructed "by hand"; for instance, if you want to map a list of street addresses or airport codes.

Background map

Applies to: SVG, JPEG/PNG

Click the "examples" link in each of the following to see some sample backgrounds.

• Worldwide: Landsat, 30m (good pseudo-color) [examples]: This option gives you a Landsat simulated-color satellite image of the earth, down to about 15-30m resolution. An excellent choice for maps larger than a few kilometers, anywhere in the world.
• Worldwide: Landsat, 30m (dull visual bands) [examples]: The same 15-30m resolution data, but using only the visible spectrum, non-colorized. The colors are very dull.
• Worldwide: physical map [examples]: GPS Visualizer will try to grab a digital map off of an external world map server and display it behind your track(s) and waypoints. (If your track covers a very small area, this won't be very useful, as the world map server doesn't have extremely high resolution; in sparsely populated places especially, you may just see flat green nothingness.)
• Worldwide: "Visible Earth" [examples]: This is NASA's "Visible Earth" (a.k.a. "Blue Marble") data: true-color imagery of the entire world. The resolution is only 1km, but it's good for very large maps.
• US: political map (TIGER street-level) [examples]: If your data was recorded in the United States, you can choose a detailed political map, including roads and streets. (NOTE: as with the worldwide political option, the larger the area covered, the farther these maps will stray from your actual data -- so don't use this option for very large areas.)
• US: Demis street-level map (uses TIGER data): Essentially the same data as the TIGER server, but overlaid upon the DEMIS map server's physical maps (see "Worldwide: physical map") and without the distortion at large areas.
• US: USGS Urban Area aerial photos: High-resolution aerial photos from 2002, many in color. The bad news is that coverage is limited to the following cities: Albuquerque, Amarillo, Anchorage, Atlanta, Baton Rouge, Charlotte, Chicago, Colorado Springs, Dallas/Fort Worth, Denver, Detroit, El Paso, Fort Wayne, Fresno, Houston, Huntsville, Jackson, Knoxville, Lexington, Lincoln, Los Angeles, Louisville, Lubbock, Mobile, Modesto, Montgomery, New Orleans, Oklahoma City, Orlando, Portland (OR), Providence, Raleigh-Durham, Sacramento, Salt Lake City, Saint Louis, San Francisco/Oakland/San Jose, Seattle, Shreveport, Springfield (MA), Stockton, Tampa/St. Petersburg, Topeka, Tucson, Washington (DC), Worcester (MA).
• US: USGS aerial photo/topo map [aerial/topo examples]: Excellent data from the USGS via TerraServer. Some of the aerial photography is a little old, but still very useful, and the resolution is an excellent 1 meter per pixel. Note, however, that if you map an area so small that your map's resolution will be greater than 1 meter per pixel, this option will fail; use the "tiles" option instead.
• US: USGS aerial photo/topo map, tiles: Both of these options assemble a background map from a series of square tiles pulled from TerraServer and hopefully lined up properly; you will probably see the tiles fill in one by one. (Note that if your map lies along the very edge of a "UTM Zone" -- the edges lie along the meridians, every 6° -- the tiles along the east side of your map may be incorrect or missing.) The only reason you would choose "tiles" over the "single image" option is the resolution issue noted above.
• US-Iowa: 2002 infrared aerials [examples]: This option only covers Iowa. The imagery is from a 2002 infrared aerial survey.
• Canada: NRCan political [examples]: These maps are amazingly detailed and accurate, but sometimes painfully slow; be patient. (They do not, however, suffer from geometric distortion.) For large-scale Canadian maps, I recommend "Worldwide: physical" mode, but the NRCan option works very well at shorter ranges (up to ~100 km).
• Canada: NRCan political + contour lines [examples]: This is the same as the "NRCan political" option, but with topographic contour lines added (these are the same contour lines available in Toporama).
• Canada: NRCan physical (low-res shaded relief) [examples]: Relatively low-resolution digital elevation data, with shading. Water bodies and waterways are drawn on top.
• Canada: CanImage [examples]: Very nice close-to-true-color satellite imagery at 15m resolution. However, in some places where apparently the really good data wasn't available, they've filled in the holes with lesser-quality data.
• Canada: NRCan + CanImage [examples]: This simply displays the NRCan line data on top of the CanImage imagery for a more complete map. (The "Vegetation," "Wetlands," and "Urban areas" layers are removed from the NRCan data.)
• Canada: Landsat false color [examples]: Gives you wildly colored Landsat imagery for most of Canada. ("Wildly" meaning that cities show up as hot pink.) Note that there are some holes in this data, and those holes will be filled in by black-and-white radar data, which is very low-resolution.
• MODIS "Terra"/"Aqua" daily imagery [examples]: NASA has MODIS sensors on two satellites named "Terra" and "Aqua" that send back fresh images, at 250m resolution, on almost a daily basis. On any given day, there might not be any coverage for your part of the world, but if there is (and if your map covers a large enough area, and if it wasn't overcast), it's pretty cool.

BG map fader

Applies to: SVG

If you include a background "fader" in your SVG map, you can change the opacity of the background even after it's been drawn. The fader is simply a series of 11 clickable boxes ranging from 0% opacity to 100% opacity. It will be drawn on the opposite side of the map from the legend, or in the top right corner if there's no legend.

Note: You can move the fader around the map -- or off the map -- by clicking on the words "background opacity" and dragging it.

BG map opacity

Applies to: SVG, JPEG/PNG

If you choose to have a background map, it's a good idea to lighten up the colors in the map -- i.e., make it partially transparent -- so that you can actually see your data on top of it. This control lets you decide exactly how opaque the background will be. 100% will produce an unaltered map, and 0% would make it invisible, so it's not even an option. (Values between 30% and 70% typically produce the best results.)

Border

Applies to: SVG, JPEG/PNG

If you select "yes," a thin black line will be drawn around the edge of your drawing.

Bounding box

Applies to: all formats

By default, the bounds of your map will be determined by the geographic extent of your data. But if you want to override the default area -- making the coverage area larger or smaller, or consistent with another map -- you can enter a "bounding box" here. A bounding box is simply four numbers separated by commas; the first number is the southern edge, then the western edge, then north, then east -- or you can think of it as the SW corner followed by the NE corner. (For example, a bounding box for the continental U.S. would be 24,-128,52,-64.) All numbers must be decimal degrees, so coordinates in the southern and western hemispheres are negative.

Note: Setting a bounding box eliminates any margin, so the dimensions of your data will be determined only by the height and width.

Calculate frequency

Applies to: all formats

If you're using the "data" form, which can colorize or resize points based on fields in your data, you can ask GPS Visualizer to automatically count up your points for you, and you can then use the calculated frequencies to resize or colorize points by "N". If you set this to "automatic," GPS Visualizer will use any and all "location" fields (city, state, ZIP code, etc.) to count your points. If you say "Using a specific field," it will use the field you specify (be sure to type it exactly as it's given in your input data), but be sure to ONLY use location-based fields or the results may be strange.

Colorize tracks

Applies to: all formats

GPS Visualizer can colorize your tracks according to speed, elevation, or some other unit -- or it can give each track its own color. By default, the minimum value is drawn in red and the maximum is drawn in magenta/violet, with a ROYGBIV spectrum in between; adjust the spectrum settings to use different color values.

Note: if your GPS data file does not include speed, course, or distance information, GPS Visualizer can estimate these measurements; they may not be 100% accurate. (Speed can only be calculated if you have a "time" field, of course).

Colorize min. & max.

Applies to: all formats

Normally, GPS Visualizer colorizes your map by simply reading the minimum and maximum value contained in your data. If you want to override the upper limit, however, you can do so here. (Any values which are higher than the new maximum will be colored the same as the maximum.)

Colorize waypoints

Applies to: SVG, JPEG/PNG, Google Earth, Yahoo

Waypoints can be colorized in the same way that tracks can: from red to purple, based on the minimum and maximum values. Note that if you choose to colorize both tracks and waypoints in the same map, things can get complicated and unpredictable.

Connect segments

Applies to: all formats

If you choose "yes" for "Connect segments," a visible line will be drawn from the end of one track segment to the beginning of the next. If you choose "no" (the default) a line will still be drawn (for continuity purposes), but it will be invisible. Some data formats -- such as GPX and OziExplorer -- actually have ways of defining track segments. For others, however, GPS Visualizer will automatically mark "end of segment" whenever it encounters a subsequent trackpoint that has no GPS fix. Therefore, if you are seeing very spotty data (i.e., you were in a forest or surrounded by buildings), you may want to turn on "Connect segments" so that your track does not show up as a series of small, incoherent dots.

Note: This setting has no effect if you use "Complete paths" drawing mode; in that case, every point is always connected.)

Discard outliers

Applies to: all formats

Some waypoint/position files have waypoints in them that you either forgot about or didn't know were there to begin with (the latter is especially true, it seems, of files dumped from Garmin receivers); these outlying points can cause problems when, for instance, you're trying to plot points in Ireland, but there's one point from Brazil that causes your map to span the entire Atlantic Ocean!

The solution is to ask GPS Visualizer to discard any waypoints which are very distant from the rest of your points. The "outlyingness" is calculated via a Z-score; this is a measure of how many standard deviations lie between a given number and the mean of the sample it came from.

Draw Forerunner laps

Applies to: all formats

Garmin Forerunner Logbook files contain "Laps"; a better name might be "splits," but that's beside the point. At any rate, you can choose whether or not these lap markers will be displayed on the map as waypoints. If you choose to display them, and you have "Waypoint descriptions" enabled, the descriptions will include the duration, length, and average speed of each lap.

Drawing mode

Applies to: SVG, JPEG/PNG

• Lines: Each track is actually made up of a number of straight lines with "squared" ends. Each line segment can have its own color, which is useful for plotting elevation or speed. (If you open the SVG in a graphics program such as Adobe Illustrator, you'll find that all of the line segments in a track are in a single group, so it's easy to select a track if you want to change the stroke width or other attributes en masse.)
• Dots: Similar to "lines," except each track point is simply represented as a round dot. (The dots are actually round-ended line segments whose two points are on top of one another.)
• Complete paths: Each track is a single object made up of a number of connected points. This makes for much smaller SVG files, but colorization by elevation, speed, etc. is impossible because all points in a track must be the same color.
• Invisible paths: The paths are drawn, but you can't see them.

Google Earth altitude mode

Applies to: Google Earth

Google Earth assigns one of two "altitude modes" to tracks: they are either "absolute" or "clamped to ground." For almost anything other than a flight, you should choose "clamped to ground"; otherwise, some of your track might actually disappear beneath the terrain, where you won't be able to see it. For airplane/paraglider/hangglider flights, however, "absolute" will show your track suspended in the air where it belongs.

Google Earth document name

Applies to: Google Earth

If you type something here, it will be used as the name of the folder that appears in the "My Placemarks" section of Google Earth. If you don't supply a document name, GPS Visualizer will try to construct a logical name based on your input files.

Google Earth file type

Applies to: Google Earth

Google Earth supports two kinds of placemark files: KML (uncompressed) and KMZ (ZIP compressed). The obvious advantage of compressed files is that they're smaller and will download faster; the only advantage to uncompressed files is that you wouldn't have to unzip them before editing them, if you needed to do so.

Google Earth initial view

Applies to: Google Earth

By default, when you open a Google Earth file that was created by GPS Visualizer, you will be looking straight down from a sufficient altitude to show all your data, and north will be at the top of your screen. If you want to change any of the defaults, feel free. Note that "tilt" is the number of degrees from vertical, and "range" is related to altitude -- if you leave tilt at zero (zenith), range is altitude.

Google Earth time stamps

Applies to: Google Earth

Beginning with version 4.0.2077 of Google Earth, placemarks can have a time stamp attached to them that can be used for various interesting animation effects. Select this option to have GPS Visualizer add time stamps to your track data (assuming your data contains time information). Be aware that when your file first opens in the Google Earth application, you may see only a small segment of your track, depending on your previous settings.

NOTE: when you choose "by track" (the default) or "none" for track colorization, your track is drawn in Google Earth as a "polyline": a long string of points defined only by latitude, longitude, and altitude. In that case, you can't assign a time to each individual point -- unless you choose to have the track duplicated as waypoints using the "trackpoints as waypoints" option.

Google Earth waypoint marker style

Applies to: Google Earth

Google Earth waypoint markers can have any kind of icon attached to them; I've provided a few of the most generic-looking built-in ones as choices. If you want another option in the menu, let me know and I'll be happy to add it.

Google Maps background type

Applies to: Google Maps

Google Maps can have three different types of backgrounds: map (a political map with street-level detail and labels on almost everything), satellite (whatever imagery Google can dredge up for that area), and hybrid (the map type overlaid on the satellite imagery, but with fewer labels and less detail at wider views). Whichever you pick, you can always change it while looking at the map later.

Google Maps scale bars

Applies to: Google Maps

By default, GPS Visualizer will request that Google add metric and U.S. scale bars to your map; change this to "no" if you don't want them.

Google Maps waypoint marker style

Applies to: Google Maps

Google Maps waypoint markers are somewhat more complicated than those in Google Earth; there is not a set of hundreds of built-icons to choose from. And if you have your own graphic that you'd like to use, it's not a simple process; you need to supply all kinds of parameters relating to the position of the icon with respect to the map. And you can't assign arbitrary colors to the icons once they're loaded.

I've created a few types of icons in a variety of "named" colors (red, blue, magenta, yellow, black, brown, etc.) that you can use in your Google Maps. If you need another style or color that's not in the list, let me know and I might be able to help.

"pins" [pin] "Google pins" [google] "Google pins (no dot)" [googleblank] "Google mini-markers" [googlemini]

"small circles" [circle] "small squares" [square] "small triangles" [triangle] "small diamonds" [diamond] "airports" [airport] "cameras" [airport] "very large circles" [blankcircle] -- this one is only useful when the points will be resized, e.g. on the "data" form.

Google Maps waypoint labels

Applies to: Google Maps

By default, GPS Visualizer does not put waypoint labels on your Google Map, although you can "mouse-over" the waypoint markers to see a "tooltip" with the name of the point. If you select "permanent labels," labels will be drawn to the right of the points -- and can be printed, which is very helpful -- but be aware that these labels cannot be moved or hidden.

GPX/CSV routepoints

Applies to: all formats

GPX and plain-text (e.g., CSV) files can contain "routes" in addition to tracks and waypoints. Usually, a route is a simply list of existing waypoints. GPS Visualizer can handle these routes in a variety of ways:

• Do not display routes or routepoints: The routes will be ignored completely.
• Convert to tracks only: Each route will be drawn as a "connect-the-dots" track between its points.
• Convert routepoints to waypoints: No line will be drawn, but each point in the route will be treated as if it were a waypoint. This is probably unnecessary, since routepoints are usually just a subset of the list of waypoints.
• Convert to tracks and include ALL as waypoints: A line will be drawn between routepoints, and the points will be displayed as extra waypoints.
• Convert: A line will be drawn between all routepoints, and routepoints that have a "name" field defined will be included as waypoints; unnamed routepoints will be included in the track but not converted to waypoints.
• Convert all points to waypoints: No line will be drawn, but every point in the route will be treated as if it were a waypoint.
• Convert only named points to waypoints: Only routepoints that have a "name" field defined will be included as waypoints; unnamed routepoints will be ignored.

Hue 1, Hue 2, Spectrum direction

Applies to: all formats

By default, GPS Visualizer colorizes your data so that the lowest values are red, middle values are yellow and green, and the highest values are magenta (i.e., a ROYGBIV spectrum), but if you don't like that setup, you can specify different colors for the minimum ("Hue 1") and maximum ("Hue 2") values. Because our eyes perceive hue in a continuous "color circle," hues are given as degrees: red=0°, yellow=60°, green=120°, blue=240°, magenta=300°, etc.

The "Spectrum direction" parameter (which is actually "colorize_reverse" in the guts of the form) controls which direction the colors go around the wheel. The default is "up," which means red would go through yellow and green on its way to blue; if you change the direction to "down," the colors will go from red through magenta and violet to reach blue.

Example: Let's say you're making a map of the concentration of a pollutant in the atmosphere, so you want low values to be green, average values to be yellow, and high values to be red to indicate too much pollution. Set Hue 1 to 120° or 135° (green) and set Hue 2 to 0° (red), and be sure to set the spectrum direction to "down"; if you leave it on "up," mid-range values will be blue instead of yellow. You could even set Hue 2 to magenta, but you would still keep the direction as "down."

Legend placement

Applies to: SVG, JPEG/PNG, Google Maps

If you choose to have your tracks colorized, you'll probably want GPS Visualizer to put a legend on your map that tells you which colors represent which speeds/elevations; in SVGs, JPEGs, and PNGs, the legend can appear in any of the four corners of your drawing. (In Google Maps, it will be in the upper right, but you can move it if you want.) If you choose colorization by track, the legend will show the names of the tracks in the appropriate colors, and in SVGs or Google Maps, clicking on a track's name will show or hide it.

Legend steps

Applies to: SVG, JPEG/PNG, Google Maps

The legend is just a list of values colorized using the same colors as the track; you can decide how many values to list. (You must have at least two steps, because the minimum and maximum will always be shown.) This parameter is ignored in "by track" colorization.

Note: If you choose a colorization parameter such as "satellites," where only whole number values are allowed, you may get weird values in the legend because the number of steps will not "line up" with the number of possible values.

Lightness & saturation

Applies to: all formats

You can alter the overriding properties of the colorization spectrum with these two controls. Note that if you set either one too low, you may as well turn off colorization completely, as it will be hard to see the difference between a very dark red and a very dark blue. I recommend keeping the saturation at 100% and turning the lightness down to 60% or 80% if you think the tracks are too bright and you want them to show up better against the background. Also, you may want to choose a lower lightness value if you are colorizing by track, because the yellows can be hard to see.

Line width

Applies to: all formats

This is simply the thickness, in pixels, of the tracks. In SVG and JPEG/PNG maps, it also affects the thickness of the outlines around the waypoint markers (for now, at least).

Margin

Applies to: SVG, JPEG/PNG

Your data will be plotted in an area equal to the width and height of your map minus twice the specified margin. If your map includes a legend or title, they will be drawn near the edge of the map, not the edge of the track area, so if the legend or title is overlapping your track, try increasing the margin.

Example: If you set the width to 600 and the margin to 40, the entire map will be 600 pixels wide but your data will only fill an area 520 pixels wide.

Max. number of points per track

Applies to: Google Maps

Very long tracks in Google Maps can cause your Web browser to grind to a halt, which is why the "Maximum number of points per track" option is there; if you upload several tracks, you may want to set it to a lower number than the default. The number of points in the track is reduced (using GPSBabel) by an intelligent algorithm that removes points from straighter segments while preserving more points in areas where they're more necessary.

Output format

Applies to: all formats

By default, GPS Visualizer draws maps in SVG format, which are great because they can be adjusted after you create them; on the other hand, they require a finicky plug-in in order to be displayed. Your other option for "flat" maps is JPEGs (or PNGs); any browser can view them with no outside help, but the output is static and unchangeable. There are advantages and drawbacks to each choice; see the FAQ for details.

You can also create interactive Google or Yahoo! Maps; these are nice because you can move around, zoom in and out, etc. However, sometimes the backgrounds aren't as useful (you can't use USGS topo maps, for example), and the maps can be very slow to display.

Another choice is KML files, if you have the Google Earth application installed. After your Google Earth file has been created, just click on the output link in your Web browser; Google Earth should open automatically.

Profile divisions

Applies to: SVG, JPEG/PNG

Normally, this specifies how many divisions GPS Visualizer will draw, using vertical or horizontal gridlines, to mark off the values on your X- or Y-axis, respectively. However, if you enter "auto" here, and your x-axis measures distance, vertical lines will be drawn in the logical locations; for instance, a 53-km track will have divisions at 10, 20, 30, 40, and 50.

Example: If you enter "4" in the "Y divisions" box, five horizontal lines will be drawn, dividing the graph into four equal slices. If you enter "1," lines will only be drawn at the minimum and maximum points. If you enter "0," no lines will be drawn at all.

Profile margin

Applies to: SVG, JPEG/PNG

The specified margin, in pixels, will be added to the top, bottom, left, and right of the area defined by the "profile width" and "profile height" variables. If your map includes a title or gridline labels, they will be drawn near the edge of the margin, not the edge of the graph area, so if they're overlapping your graph, try increasing the margin.

Profile width & height

Applies to: SVG, JPEG/PNG

These controls the width and height, in pixels, of the data that will be graphed. Note that whatever value you specify for the "margin" will be added to the profile on all sides.

Profile X- and Y-axis

Applies to: SVG, JPEG/PNG

You can draw a profile using almost any measurements as the horizontal and vertical axes; the top and bottom of the axis are defined by your tracks' minimum and maximum values in that measurement. "Distance" is a special case, in that it is calculated by GPS Visualizer; the other measurements are stored in the GPS data -- and please note that distance is only an estimate!

Note: if you want, you can choose a colorization mode that is not the same as either of the axes; in this way, you can actually plot three different parameters on the same graph!

Profile X/Y min./max.

Applies to: all formats

If you don't specify minimum and maximum values for the axes of your profile, GPS Visualizer will automatically calculate them based on your data. But if you want to override the min. and max., enter new values here. You do not need to supply units: if it's an elevation profile in U.S. units, your numbers will be interpreted as feet; if it's a speed graph in metric units, GPS Visualizer will assume you meant km/h; and so on and so forth. Note that any values which fall outside your specified range will still be drawn; they'll just appear to be "off-screen."

Remote data URL

Applies to: all formats

Some of the input forms give you the option to enter a URL from which GPS Visualizer will pluck the coordinate data. So far, this only works in a few limited situations.

Resize data; Min. & Max. waypoint radius

Applies to: all formats

This allows you to have your waypoints resized based on a parameter such as altitude, signal-to-noise ratio, or something else. Note that if you set the minimum size to zero, your points will be compared on a scale that starts at zero, not at your minimum point (and the sizes of the circles will be assigned based on the square root of your data). If you want your smallest data point to be miniscule, set the minimum to 1 or 0.5, not 0.

Example: If your quantifiable data ranges from 10 to 20, and you set the min & max radius to 0 & 12, the "20" point will have a radius of 12, but the "10" will not be zero; it will have a radius of about 8.5 (it's not simply half of the maximum because they're proportional by area; 8.5 is the square root of half of the square of 12). On the other hand, if your data ranges from 10 to 20 and you set the min & max to 1 & 12, the "10" point will indeed get the minimum value of 1.

Reverse track points

Applies to: all formats

The main effect of this is simply to put the track's label at the end of the track instead of the beginning, if track names are turned on. If the drawing mode is set to "dots," reversing the drawing order has another, more subtle effect: because the dots tend to overlap one another to form colored crescents, reversing the drawing order makes the crescents appear to be pointing in the "correct" direction.

Scale length

Applies to: SVG, JPEG/PNG

For SVG & JPEG/PNG drawings only. Note that the scale length is calculated based on the longer side of your drawing, and it is also drawn on the longer side. If you want it on the short side, you'll have to edit the SVG manually.

• If you do not want a distance scale, enter zero or leave this box blank.
• If you set the scale length to "auto," a sensible scale length will be chosen. For example, if your drawing is 4 km wide, the scale will show 1 km.
• If you enter a number less than or equal to one, either as a decimal or a fraction (the default is "1/2"), a scale line will be drawn that represents that fraction of the total width of your track data.
• If you enter a number greater than one (but with no units after it), your scale will be that many pixels in length.
• If you enter a number followed by "km," "m," "mi," "miles," "ft," or "feet," you will get a scale line of exactly that length. (Be careful not to enter a length that exceeds the size of your drawing, or it will not be a very helpful scale.)
• Example: let's assume you have a track whose longest dimension is 100 km, and you have specified 500 pixels in the "maximum dimension" field. If you enter "1/4" for the scale length, the scale will be 125 pixels long and will represent 25 km. If you enter "200," the scale will be 200 pixels long and will represent 2/5 of your maximum dimension, or 40 km. If you enter "50 miles," the scale will represent 80.47 kilometers and therefore will be (80.47/100)*500 = 402 pixels long.

Show waypoints

Applies to: all formats

• None: Any waypoints are ignored and simply not plotted in your map. (However, if you only upload waypoint files, this will be overridden and all waypoints will be displayed.)
• In bounds of tracks only: Waypoints are only plotted if they fall within the rectangle defined by the maximum and minimum longitude and latitude of the track(s) that you're plotting. (Example: if you have a track that goes from Philadelphia to Boston, a waypoint in Baltimore will not be plotted because Baltimore is further west -- and south -- than the range of the track. A waypoint in New York City will be plotted, however.)
• In bounds of tracks plus margin/padding: Waypoints are only plotted if they fall within the rectangle defined by the maximum and minimum longitude of the tracks that you're plotting, plus the margin or padding. (Example: if you have a track that goes from Philadelphia to Boston, a Baltimore waypoint might be plotted, but only if the margin is wide enough. A waypoint in Chicago will almost certainly not be plotted.)
• All (bounds are defined by waypoints): All waypoints will be plotted. If some of the waypoints are outside of the area defined by your tracks, the bounds of the map will be redefined based on the waypoints, and the margin will be added to the new bounds. (Example: If your track goes from Philadelphia to Boston but you also upload waypoints in Chicago, you will end up with a map that extends from Lake Michigan all the way to the Atlantic Ocean, and your Philadelphia-Boston track will only cover a small fraction of the graphic.)

Single-point map width

Applies to: all formats

If your data consists of a single waypoint, GPS Visualizer doesn't know how large your map should be. The number you enter will be interpreted as kilometers unless you type "mi" or "miles" to indicate a figure in miles.

Skip factor

Applies to: all formats

If you have a very long track with a lot of points in it, you can choose to have GPS Visualizer skip some of the points so that the SVG you create has a more manageable file size. If you specify a "skip factor" of 10, every 10th point will be plotted. (A skip factor of 1 -- or nothing -- means that every point will be plotted.)

Note that GPS Visualizer does not do any averaging to compensate for the missing data; it simply ignores the points completely. Therefore, this has the potential to really mess up your drawings if you have tracks with breaks between segments.

Text size

Applies to: SVG, JPEG/PNG

The value (in pixels) that you specify here will set the size of the legend, scale, track names, and waypoint names; in addition, the title (if present) will be 1.5 times this size, and any track/waypoint descriptions will be 3/4 of this size.

Tickmark interval

Applies to: all formats

You can choose to have tickmarks placed along your tracks at a given interval, to mark your progress. You would usually a distance here; e.g., "10 mi" or "1 km". (If you don't supply a unit, it will be assumed that you mean kilometers.) However, you can also supply a time interval, if your file contains time information in a supported format: enter "s" as the unit for seconds elapsed from the start, or "min" as the unit to see the actual time printed on the map.

Please note that the distance traveled is only an approximation, and it will very likely be a larger number than your GPS receiver tells you, because every point is used in the calculations. You can try skipping points (see the Skip factor option) to smooth it out a little.

Time offset

Applies to: all formats

Sometimes you GPS data contains time stamps that are in a time zone different from your own -- usually GMT. Enter your time zone here, in hours (for example, U.S. Pacific time is -8 and Central European time is +1), and GPS Visualizer will try to compensate.

Title

Applies to: SVG, JPEG/PNG

If you want a title at the top of your drawing, type it here. (For Google Maps, you can easily add a title later by simply editing the HTML.)

Track descriptions

Applies to: SVG, JPEG/PNG

If you select "yes," track descriptions will be displayed under the track names.

Track hue default

Applies to: all formats

If you don't colorize your tracks, this color will be used -- unless your track data file has a color specified in it.

Track names

Applies to: SVG, JPEG/PNG

If you select "yes," and if your map is in a format that supports it, a text label will appear at the beginning of the track with the name of the track. If a track does not have a name defined, the file name (minus the suffix) is used as the track name.

Note: if you choose "by track" colorization, you probably don't need track names; it might be simpler to include a legend that shows which colors belong to which tracks.

Track opacity default

Applies to: all formats

Most map formats allow you to make your tracks less than 100% opaque, so that a little bit of the background shows through. If you choose a value less than about 70%, your tracks will be hard to see.

Trackpoints as waypoints

Applies to: Google Earth

Typically, a track will simply be drawn as a line. If you select the "Draw trackpoints as waypoints" option, each trackpoint will also become a waypoint that can be clicked on to get more information about that point. (This actually works in all output formats, but is most practical in Google Earth. In Google Maps, it's potentially useful but problematic because displaying markers in Google Maps is so slow.)

Units

Applies to: all formats

Choose "metric" if you want distances and elevations to be output in meters/kilometers; choose "U.S." for feet/miles. (The default is metric because that's how most GPS receivers record their data -- and because it just makes more sense.)

Waypoint color default

Applies to: all formats

You can assign individual colors to each of your waypoints (if your input data file format supports that sort of thing), but this parameter sets the default for any points that don't have a color specified. In Google Maps, the default is usually set to a bright color like red; in other types, black or black-and-white will be the default "uncolored" state.

Please note, by the way, that waypoints in Google Maps have a limited list of colors to choose from, and that list appears in the "default waypoint color" menu on the Google Maps form: Google default, aqua, black, blue, brown, cyan, fuchsia, gray, green, lime, magenta, maroon, navy, olive, orange, pink, purple, red, silver, tan, teal, violet, white, & yellow. Other map formats, including Google Earth, can use any HTML-formatted color.

Waypoint descriptions

Applies to: all formats

If you select "yes," any waypoint descriptions will be displayed under the waypoint names. (If you choose not to have the waypoint names displayed, the descriptions will generally be displayed in place of the labels.)

Waypoint display padding

Applies to: Google Maps, Google Earth, Yahoo

This works like the "margin" setting in SVG or JPEG/PNG maps: it is a buffer zone around your tracks that determines which waypoints will be displayed (see Show waypoints for more info). In Google and Yahoo maps, it's a percentage rather than a number of pixels because the maps can be panned and zoomed, making pixel measurements somewhat irrelevant.

Waypoint fill opacity

Applies to: SVG, JPEG/PNG

This is the opacity, from 0 to 100, of the center of your waypoints.

Waypoint outline opacity

Applies to: SVG, JPEG/PNG

In SVG or JPEG/PNG maps, this is the opacity, from 0 to 100, of the line around the circumeference of your waypoints. In Google Earth KML files, this parameter is used for the overall opacity of the marker icon.

Waypoint names

Applies to: all formats

If you select "yes," a text label will appear next to each waypoint with the name of the waypoint (if one is present).

Waypoint radius (unresized)

Applies to: SVG, JPEG/PNG

This simply controls the size, in pixels, of the circles that indicate waypoints on your map. If you have chosen to resize your waypoints according to some data field, any points that don't contain data for that field will get this default.

WEP colors

Applies to: all formats

This only applies to wireless internet log files ("wardriving"). If you turn on WEP colors, unsecured access points will appear in green while WEP-enabled ones will be red.

Width & Height

Applies to: all formats

This is the width and height, in pixels, of the window in which the map will appear. The map will be zoomed in/out an appropriate amount to show all of your data.

If you set either the height or the width to "auto" (the default), a sensible value will be chosen based on the shape of your data, but it will never be more than the fixed measurement. In other words, a map with height set to auto will never have a vertical orientation; if you have data that is mostly north-south and you want a "skinny" map, set the height to a specific size and change the width to auto.

WiFi file mode

Applies to: all formats

Raw NetStumbler and WiFiFoFum log files contain a long series of data points for each base station you detected, plus a "summary" data point for each station. (Raw WiFiFoFum logs doin't contain the summary point, but GPS Visualizer calculates an estimated center point for you.) You can choose to display only the longer tracks, only the summary points, or both. Be aware that if you do both, it can get very messy if you have a large log file.

Zoom control

Applies to: Google Maps, Yahoo

By default, GPS Visualizer will request that Google or Yahoo add a pan/zoom control to your map; you can turn it off, but that will make navigation more difficult, so be careful.

©2007 Adam Schneider, .  . E-mail: schneider pobox com.