GPX

GPS Exchange format, a generic format used to extract data recorded by GPS devices.  GPX files typically contain Latitude/Longitude coordinates for points and lines, often with elevations and at times with detailed information on the operation of the GPS device at the time the data was acquired.  

 

The sample GPX file imported in this topic is similar to that used in the Manifold 9 - A Walk in the Rain Forest video.

 

dlg_import_gpx.png

 

To import from GPX format:

 

  1. Choose File-Import from the main menu.

  2. In the Import dialog browse to the folder containing data of interest.

  3. Double-click the file ending in .gpx for the data of interest.

  4. Tables and drawings will be created.

 

eg_import_gpx01_01.png

 

The Map file above shows the other drawings as layers.   Some drawings might be empty:  For example, if the GPS has no routes or waypoints those drawings might not contain any data.   

 

We can double-click on either the map or the drawings to view them.   For a more interesting display, we first create a new data source using a Bing street maps imageserver as shown in the Example: An Imageserver Tutorial topic.   We then create a map and drag and drop the Bing layer into the map, and then we drag and drop the parkland TrackPoints Drawing into the map.   We also add a Bing satellite layer.

 

eg_import_gpx01_02.png

 

The track points drawing appears using the correct projection, in the right location.  We have colored the dots in the track points using Style to provide a bright green color.    From the location of the town of Mackay, right away we can see the GPS information was collected in Australia.

 

eg_import_gpx01_03.png

 

Zooming in and switching to the satellite view we can see the points that were collected by the GPS.

 

eg_import_gpx01_04.png

 

Opening the parkland TrackPoints table we can see the data associated with each record.  Most GPX files import with NULLs in most of the data fields, since very few people will bother to export the many parameters the GPS might collect.     Note that the table has a gray background, indicating it is not editable nor selectable.  That is because the table does not have an index.

 

Using the procedure given in the Add an Index to a Table topic, we take a moment to add an mfd_id key field and corresponding index.

 

eg_import_gpx01_05.png

 

That makes the table selectable, and also allows us to make selections in the drawing.

 

eg_import_gpx01_06.png

 

For example, if we want to get an idea of the elevations near the beach in the illustration above, we can select those points near the beach.

 

eg_import_gpx01_07.png

 

In the table we use a filter to show only selected records.

 

Notes

Extracting latitude and longitude - The GPX dataport creates a geometry field, called Geom, to capture the position of each point, as seen in the illustration below.  To create fields that provide explicit latitude and longitude values, as might be required by some other applications, use the procedure shown in the Example: Create a Geocoded Table from a Drawing  topic.

 

eg_import_gpx01_08.png

 

See Also

Tables

 

Drawings

 

Maps

 

Filters

 

Selection

 

Add an Index to a Table

 

Example: Spectacular Images and Data from Web Servers

 

Example: An Imageserver Tutorial

 

Example: Create a Geocoded Table from a Drawing

 

Videos

Manifold 9 - A Walk in the Rain Forest