For GPX data such as activity logs,
you may want
to:
- remove unnecessary data recorded while staying in the same place
- reduce processing load when there are too many points
For the former case, use downsampling that deletes the target data from the data itself.
For the latter case, use "map display downsampling" because you want to keep the original data unchanged while making the display and operation lighter.
In this case, the following setting is also effective in addition to downsampling.
- Hide point display: Map screen [View]-[Map]-[Point]-[Show]=OFF
Turbo GPX provides the following downsampling functions.
| Function | Data impact |
|---|---|
| Delete the target data from the list screen | Yes |
| Delete data using the map edit function | Yes |
| Map display downsampling | No |
Delete the target data from the list screen
Select the data you want to delete in the list screen, then
delete it.
Click a point in the list or on the map to
find the point to delete.
When deleting a range between two
points, it is useful to find the two points on the map and use the
jump function.
Deleting data from the list on the main
screen removes the target data.
Delete data using the map edit function
Open the map edit screen from the list screen, select the data
you want to delete, then delete it.
Map display downsampling
This function sets which points to keep instead of deleting
data.
This function does not affect the data itself (the list
on the main screen), but the downsampled result can be applied to
the list screen.
Downsampling is applied only to points.
It is not applied to tracks.
| Function | Description |
|---|---|
| Step | Sets the step interval |
| Limit | Sets the maximum total number of points |
| Distance | Sets the distance between GPX points |
| Time | Sets a time pattern (wildcards supported) |
| PhotoLink | Keeps only points with photo links |
Step (interval)
Keeps points at the specified step interval.
Points are
thinned at a fixed interval, reducing processing load.
Limit (maximum count)
Sets the number of displayed points to the specified value.
By setting a maximum display count, processing load can be kept
stable regardless of the data size.
Distance
Keeps points that are at least the specified distance away from
the previously accepted point.
This can reduce dense point
clusters in low-speed sections.
Time (time pattern)
Keeps points that match the specified hour/minute/second
pattern (wildcards supported).
PhotoLink
Keeps only points that have a photo link setting.
This
function is mutually exclusive with the other downsampling
functions.
Multiple conditions
Multiple conditions can be set except for PhotoLink.
They
are applied in the following order: Step → Limit → Distance →
Time.
Protected points
Protected points are points that remain regardless of the
downsampling conditions.
The following points are
protected.
- First point / last point
- Photo link points
- Segment boundary points
- Color-coding overlap points
Applying the result to the main screen
Map display downsampling affects only the map display.
To
apply the displayed data to the list on the main screen, run
[Map]-[Apply Downsampling] on the main screen.
Downsampling examples
Target data for
downsampling
The following data will be displayed with downsampling.
Delete the
target data from the list screen
Click the target point on the map.
Because the data after this point will be deleted, select the range to the end of the list screen.
Use [Right Click]-[Delete] to delete the selected data.
The data has been deleted from the list.
Color-coding settings
The color-coding settings are set to:
- Distance Interval
- 500 m
Downsampling: Step=20
Step downsampling is set to 20.
Downsampling: Limit=100
Limit downsampling is set to 100 points.
The total number is 100 plus protected points.
Downsampling:
Distance=100
Distance downsampling is set to 100 m.
Downsampling:
Time=every exact minute
Time downsampling is set to **:00:**.
No color coding
To perform more exact downsampling, set color coding to None.
This is because segment boundaries become protected points when color coding is enabled.
Step downsampling is set to 20.
The point count changed from 98 with color coding to 52.
Downsampling:
Step=20 & Limit=10 & Distance=100
Multiple conditions are set: Step downsampling=20, Limit downsampling=10 points, and Distance downsampling=100 m.
