OGPS

Online Help

About this help page

This is an online help page that may be updated over time. If you might need help while you do not have Internet access (while traveling, for example), you should save or print a permanent copy of this page.

Last updated: November 15, 2020

Installation

OGPS can be installed by downloading the zip file from the OGPS home page, opening the zip file, and copying the main executable file (OGPS.exe) to a folder somewhere on your computer. To have your computer open *.ogps files with OGPS, start OGPS and click Help > File Association > OGPS Files.

OGPS requires the Microsoft .NET Framework Version 2.0, which can be downloaded from Microsoft's website if your computer doesn't already have it. Note that different versions of the .NET Framework are independent of each other. As of February 2012, the 32-bit version of the Microsoft .NET Framework Version 2.0 could be downloaded from this page.

What you need to use the application

To display one or more tracks over an orienteering map, you need two things:

An image file containing your map. This can be obtained by opening the OCAD file and exporting an image, or by using a flatbed scanner or digital camera. A resolution of about 200 dpi is recommended, but not required.
One or more files containing the tracks you want to analyze. These track files can come from Garmin Training Center or they can be standard GPX files. Later versions of Garmin Training Center allow you to export a single activity, rather than your entire history.

Note (2018-09-15): If you have a newer Garmin device that creates FIT files, you can import these files into Garmin Training Center and export the activities as TCX files. You can also export TCX files from Garmin Connect, which will add elevation data if the device did not record it.

Starting a new OGPS file

To align a track with a new map, follow these steps:

If an OGPS file is already open, click File > New.
Click File > Open Map Image and find your map image file.
Click File > Load Tracks, find your track file, and then select which track you want to load.
Click on the Calibration tab if it is not visible.
Find two points of your track (such as lap points or sharp corners) that you can accurately place on the map.
Using the right mouse button, drag each track point to the corresponding map location. This will create calibration points.
If necessary, create more calibration points to improve the alignment.
To manually edit or delete a calibration point, left-click on it to select it.
To see what effect different calibration points have, you can enable/disable them using the "Use this point" checkbox.
Once you get your track aligned properly, be sure to save the OGPS file.

Some noteworthy information:

It is possible to load multiple tracks (from multiple files) at once. You don't have to repeat the track loading procedure.
Tracks can be loaded from other OGPS files as well as from Garmin Training Center and GPX files.
When loading tracks from GPX files, the times of any waypoints in the files are taken as lap times. (The waypoint coordinates are ignored.)
The mouse wheel can be used to zoom in and out.
Double-clicking on a track's entry in the track list tells OGPS to zoom and scroll to its location and, if the Track tab is visible, to select all of its points.
OGPS has various keyboard shortcuts, which are listed in the Keyboard commands help section.

Opening and saving OGPS files

After aligning a track with a map, you should save the OGPS file. Then you can see your route later without recalibrating the map. Furthermore, if you run a race in the same area as a previously recorded race, you can then open the OGPS file for the previous race and simply replace the track with your new one.

The following information is saved in OGPS files:

The name of the map image file
The location of the map image file if it isn't in the same folder as the OGPS file
The calibration points
The control circles
The tracks, including their names, checked statuses, and assigned colors

The following information is not saved in OGPS files:

The map image itself
The display settings

It is recommended that you keep the map image files in the same folder as your OGPS files. This way, you can move files around without having to relocate map image files.

Files saved by versions 1.0.0 to 1.2.0 of OGPS do not contain elevation or heart rate data. This data can be obtained for past races by reloading the tracks.

Exporting images

To export an image of the map and tracks, select "Export Image" from the File menu and then choose which combination of map area and zoom level you want. You can choose from a variety of image formats. The PNG format is probably best if the map image was exported from OCAD. The JPEG format is probably best if the map image came from a scanner or digital camera and a small file size is desired.

The Export Image feature exports everything that would appear on the map. This includes any temporary points shown while calibrating the map or while obtaining track information. If you do not want such points included, make sure that none are being displayed.

Exporting georeferenced images

The Export Image feature (described above) also lets you export georeferenced map images. These images start out as whatever would be produced with the chosen map area and zoom level, but are then transformed (with the current calibration settings) to correct distortions in the map. This transformation may take a few minutes for large images.

The following file formats are available:

Georeferenced KMZ with JPEG: Creates a KMZ file with an embedded JPEG image.
Georeferenced KMZ with PNG: Creates a KMZ file with an embedded PNG image.
Georeferenced TIF+TFW+PRJ: Creates a zip file containing a TIFF image and TFW and PRJ files for georeferencing.

KMZ files can be opened in Google Earth and used as Garmin Custom Maps. The JPEG image format is required for Garmin Custom Maps. The PNG image format provides better image quality but may result in large file sizes for map images that came from a scanner or camera.

Zip files with TIF/TFW/PRJ files can be extracted and used in some GIS software. The complete zip files can also be imported into the Avenza Maps smartphone app.

Factors affecting accuracy

Tracks normally align fairly well with orienteering maps once a few calibration points are added. Sometimes, however, it is difficult to make tracks align with a map. This can be caused by the following factors:

Map inaccuracies: Although a map may be suitable for orienteering, it may not accurately represent the terrain as an aerial photograph would. Corrections or additions done by fieldwork alone can be significantly off.
GPS inaccuracies caused by tree or cliff cover, ionospheric distortion, or lack of satellites. See the Wikipedia article on GPS for more information. GPS inaccuracies are more noticeable on smaller scale maps.

Control circles

Circles with names or numbers can be added to the map using the Circles tab. Read the instructions on this tab for details.

Once the map is calibrated, it is possible to export the circles into a GPX file as waypoints. The waypoints can then be sent to your GPS using a program such as Garmin MapSource. This feature may be useful for course setting. However, if you decide to use this feature for course setting, note the following:

The waypoints are exported using the current calibration settings. Thus, they could be inaccurate, especially if they are not near any calibration points.
You may end up with poor courses if you follow your GPS while checking control locations. Without actually orienteering, you may not notice map inaccuracies or other factors that would make it difficult to find the controls without using a GPS.

It is also possible to import waypoints from GPX files. When doing so, it is especially important to note that the circles are stored by their map (x, y) coordinates. Thus, when waypoints are imported as circles, the current calibration settings are used to position the circles on the map. Changing the calibration settings afterwards will not move the circles.

Route playback

Using the Playback tab, you can see the tracks played back at a proportional speed. For example, at a playback speed of 60X, each minute of orienteering is replayed in one second. Note that you can manually reposition the moving slider at any time (during playback or while playback is stopped).

If you have multiple tracks, selecting the "Mass Start" option will make all the tracks start at the same time. This is useful for comparing races and seeing where competitors gained or lost time. Deselecting the "Mass Start" option will make the tracks play with respect to the date and time that they were recorded. (Any periods of time not covered by any track will be skipped.)

Track tab and graph

On the Track tab, you can select how the tracks are colored. The tracks can be colored individually (by the colors assigned to them in the track list) or according to speed, elevation, or heart rate. When coloring the tracks according to speed, elevation, or heart rate, the range of values matched with the colors is automatically set. The colors themselves can be changed using the Display Settings window.

The Track tab also allows you to see a graph of the speed, elevation, or heart rate data of one track at a time. This graph appears below the map whenever the Track tab is visible and the "Show Graph" option is selected. Combo boxes above the graph allow you to select which track is graphed, whether the horizontal axis represents time or distance, and what measurement (speed, elevation, or heart rate) the vertical axis represents. Changing which measurement is used to color the tracks will also switch the graph to that measurement, unless you hold down the Ctrl key. Finally, the graph range for each measurement can be adjusted by holding down Shift and/or Ctrl while dragging the graph up or down. See the Keyboard commands help section for details. Note, however, that graph range adjustments are not permanent and will be lost once another file is opened or started.

While the Track tab is visible, you can right-click or right-drag on a track and/or its graph to obtain various information about a track point or track segment. This information has many uses, including the following:

Getting the date, time, coordinates, and other data of a single track point
Seeing how much time was lost due to mistakes
Comparing distances traveled to straight-line distances
Seeing the average speed, elevation, or heart rate over part of a track

This tab also allows you to edit tracks. Lap circles (which are automatically numbered) can be added to and removed from tracks by pressing the L key while individual track points are selected. Selected track points can be deleted by pressing the Delete key. Deleting all of a track's points will delete the track itself.

The "Sample Speed at Points" option on this tab creates a smoothing effect for the track coloring and graph of speed data. Normally, speed is associated with track segments because each segment represents a certain distance and elapsed time. However, with this option selected, the application will associate speed with track points using the average of the adjacent segment speeds. The speed data is then processed just like elevation or heart rate data for coloring the tracks and plotting the graph. Note that this option has no effect on the information displayed for selected track points or segments.

Track list

A new feature of version 3.1.0, the track list makes it easier to manage many tracks within a single OGPS file. The track list is shown in the bottom-right corner of the main window when the "Show Track List" option in the Options menu is selected.

Each track in an OGPS file has a name, a checkbox, and a color, all of which can be changed by clicking (or right-clicking) on the track's entry in the track list. The order of the tracks can also be changed.

The track checkboxes, along with three items in the Options menu, can be used to make the map appear less cluttered and also to make point selection easier. The "Unchecked Tracks Visible" option controls whether unchecked tracks are visible. (If they are visible, then settings in the Display Settings window control how they appear.) The "Unchecked Tracks Clickable" option controls whether points can be selected from unchecked tracks, assuming they are visible. The "Consider Highlighted Track to be Checked" option will cause whichever track is currently highlighted in the track list to be treated as if it were checked, regardless of its actual checked status.

Display settings

You can use the Display Settings window (accessible by clicking View > Display Settings) to adjust the color and size of the tracks and other features drawn on the map and graph. The transparency/opacity of many features can also be adjusted. Buttons at the bottom of this window allow you to revert the display settings to what they were when the window was opened, to what they were when the application was started, and to the application defaults.

Sometimes, the best way to make the features stand out is to shade the map. The map shading opacity slider on the Display Settings window makes the entire map image closer to the map shading color. To make the map image darker, for example, set the shading color to black and move the slider a few notches to the right. (Moving the slider all the way to the right will completely replace the map image with the shading color.)

Performance considerations: Tracks colored by speed, elevation, or heart rate are rendered differently when they are not completely opaque. As a result, you may notice a decrease in map drawing performance if you have transparent tracks colored by speed, elevation, or heart rate. Track points used to indicate point selection are also drawn differently when not completely opaque, but this is unlikely to have a significant effect on performance.

Measuring tool

A new feature of version 3.2.0, the measuring tool allows you to measure arbitrary distances on the map. The measuring tool can be shown by clicking View > Measuring Tool or by pressing Ctrl+E.

When the measuring tool is shown, points can be added to a measuring line by right-clicking. The measuring tool displays the current distance of the measuring line and has a Reset button and an Undo button. The Reset button clears the line, while the Undo button removes the last point from the line. These actions can also be performed by pressing Ctrl+E and Ctrl+Z, respectively. Pressing Escape will hide the measuring tool. Hiding the measuring tool also clears the measuring line.

Distances reported by the measuring tool are calculated by performing reverse transformations with the current calibration settings. Thus, if you have more than two calibration points in use, the reported distance of the measuring line will probably depend on its position on the map, not just on its length in pixels.

File association

If you want to open OGPS files by double-clicking on them in Windows Explorer, you can associate *.ogps files with OGPS by clicking Help > File Association > OGPS Files. You can also associate GPX and TCX files with OGPS. When OGPS is told to open a GPX or TCX file on startup, it will start a new file and then load the tracks from the track file it was told about.

Technical details: When OGPS associates *.abc files with itself, it attempts to create or overwrite the following registry values:

HKEY_Current_User\Software\Classes\OGPS.File\shell\open\command\(default) = "ExecutablePath" "%1"
HKEY_Current_User\Software\Classes\.abc\(default) = OGPS.File

After you associate a file type with OGPS, Windows should automatically change the icon for that file type, although it might not do so immediately.

Note that there are currently no options for disassociating file types from OGPS. You can use Windows Explorer or another program to change file associations.

Keyboard commands

For easy reference, the following table lists various keyboard commands available in OGPS. All clicking and dragging is with the left mouse button, unless indicated otherwise.

Any Tab
Up, Down, Left, Right	Scroll the map.
Plus, Minus, Ctrl+Up, Ctrl+Down	Zoom the map.
Shift+Escape	Cancel track highlighting in the track list so that no track is highlighted.
F5	If no map image is loaded, reset the size of the imaginary map image to the current size of the map view. (This affects track placement when there are less than 2 calibration points.)
Ctrl+D	Open the Display Settings window.
Ctrl+E	If not measuring, show the measuring tool. If measuring, reset the measuring tool.

Calibration Tab
Escape	If currently dragging a calibration point, cancel the dragging. Otherwise, clear the selection.
Enter	Save the currently selected calibration point.
Delete	Delete the currently selected calibration point.
Page Up, Page Down	Cycle through the calibration points.
Shift+Click	Set the map (x, y) coordinates to where you click.
Ctrl+Click	Set the track (latitude, longitude) coordinates to the coordinates of the nearest track point.
Shift+Ctrl+Click	Set the track (latitude, longitude) coordinates to where you click (relative to the track) by doing a reverse transformation.
Shift+Right-drag	Create a calibration point as usual, but take the track (latitude, longitude) coordinates of where you click (as in Shift+Ctrl+Click) instead of the nearest track point.
X	Enable or disable the currently selected calibration point.
L	Create or remove a lap circle at the track coordinates (if that location is a track point).

Track Tab
Ctrl+(Radio button)	Color tracks according to the measurement indicated by the radio button, but do not switch the graph to that measurement.
Page Up, Page Down	Select the previous or next track.
Home, End	Extend the selection to the beginning or end of the track.
Ctrl+PgUp, Ctrl+PgDn	Select the previous or next leg.
Ctrl+Home, Ctrl+End	Extend the selection to the beginning or end of the leg.
Escape	Clear the selection.
L	Create or remove a lap circle at the currently selected track point. (Only one track point must be selected.)
Delete	Delete track points according to the following rules: 1. If an entire track is selected, delete the track. 2. If a track segment of 3 or more points is selected, delete the inner points and leave the outer 2 points selected. 3. If a track segment of 2 points is selected and one point is an end point of the track, delete the end point and leave the other point selected. 4. Otherwise, delete the selected point(s) and clear the selection.
Ctrl+Right-click	Select points only from the track that is currently highlighted in the track list. (This is helpful when you have two or more tracks that are very close together.)

Graph
Ctrl+Left, Ctrl+Right	Scroll the graph.
Ctrl+Plus, Ctrl+Minus	Zoom the graph.
(Shift and/or Ctrl)+Drag	Adjust the graph range for the measurement currently being graphed as follows: - The Shift key 'frees' the upper end of the range. - The Ctrl key 'frees' the lower end of the range. - With one end free, dragging the graph shrinks or stretches it. - With both ends free, dragging the graph shifts it up or down.
Double-click	Reset the graph range for the measurement currently being graphed.

Measuring Tool
Ctrl+E	Reset the measuring tool.
Ctrl+Z	Remove the last point from the measuring line.
Escape	Hide the measuring tool.
Alt+Right-(click or drag)	Instead of adding a point to the measuring line, perform whatever action would be performed if not measuring.

About the application

OGPS was developed by Thomas Graupner. The matrix transformation module used in earlier versions was written by Dave Graupner.

This application was made primarily for the personal use of the developer. The current version is freeware, meaning that all of its features are completely free to use forever. If you wish to make a donation, please see the donations page.

Legal disclaimer: This application is provided "as is" with no warranties of any kind. Use at your own risk.

(Back to OGPS home page)