7 votes
Accepted

Inaccurate altitude GPS data with my Android?

There could be a number of problems in play here depending on where you are, what the terrain is like, and what the capabilities of your device are? If your device uses pressure sensors they may not ...
  • 3,492
5 votes

Some companies receiving GPS data from vehicles when GPS cannot send any data?

Typically this is done via the mobile network. You are right about the cellhpone network being unreliable. That's why a lot of the tracking system would cache the GPS positioning data locally in case ...
5 votes
Accepted

How to rename several layers at the same time?

You could try using the following in the Python Console: x = 0 for layer in QgsMapLayerRegistry.instance().mapLayers().values(): x = x + 1 layer.setLayerName(str(x).zfill(2)) The zfill() ...
  • 73.4k
4 votes
Accepted

How to split a GPX track file into several files of N trackpoints each?

Surprisingly it seems gpsbabel indeed can't do it. But at least it can help by first converting to csv. Then I split the result with Unix' split and convert back to gpx with gpsbabel. A similar ...
  • 156
4 votes
Accepted

Create GPX track in R. writeOGR function

Figuring out the GPX driver options for rgdal is headache-inducing. Writing a linestring as you've done here will cause it to write a route layer - if you write a multilinestring it should create a ...
  • 14.6k
3 votes

GPS: what limits the _rate_ of change in altitude?

There is no difference in the rate of change of altitudes with respect to planimetric coordinates. Satellite navigators calculate their position in a geocentric Cartesian system. At the equator, at ...
3 votes

Inaccurate altitude GPS data with my Android?

More answers can be found here: https://stackoverflow.com/questions/11168306/is-androids-gps-altitude-incorrect-due-to-not-including-geoid-height https://android.stackexchange.com/questions/90152/...
3 votes

Accurately tracking location in outback?

Most basic GPS devices have a recording mode that will store a point every so often, so you could try that. Otherwise it depends how far out of town you go, the local topography and vegetation. I ...
  • 3,527
3 votes
Accepted

Wrong track building with OpenLayers

You could calculate the angles at each vertex on the linestring and remove any where the angle is sharper than your requirement. A function such as this would do it. function checkAngles(feature, ...
  • 10.8k
3 votes
Accepted

Auto generating waypoints to a GPX file along track (hiking path - not as crow flies)

Using QGIS 3.2 Add a base map Install the plugin QuickMapServices. Plugins menu > manage and install plugins > find and install Quickmapservices The QuickMapServices button is on the Manage ...
  • 23.5k
3 votes

How to rename several layers at the same time?

try this: canvas = qgis.utils.iface.mapCanvas() allLayers = canvas.layers() i = 1 for bla in allLayers: name = "layer_"+str(i) bla.setLayerName(name) i = i + 1
  • 188
3 votes

Calculating distance travelled along track in QGIS?

Field Calculator is the abacus icon. Select the layer you want and open the field calculator. Insert details for new field and write the expression $length and click 'ok'. A new column has been ...
  • 4,302
3 votes

Calculating distance travelled along track in QGIS?

The reason why you do not see the length in the attribute table is that the length (and area) of features are implicit attributes of their geometries. They are not stored by default, they need to be ...
  • 9,303
3 votes

Advanced editor tracking in ArcGIS Pro

No, there isn't anything out of the box that will capture changes to individual fields. Editor tracking in ArcGIS, when enabled on a feature class will give you the following information: Created By ...
  • 21.5k
3 votes
Accepted

Reconstruct Tracks

Use Menu Processing / Toolbox / Points to Path, set Order field to the field with your time information (or any other order field, in my case simply the id) and set the RouteID field as Group field to ...
  • 48.3k
2 votes

Create tracks from GPS points honoring polygon barriers

Here's a solution using the gdistance package in R for computing shortest paths according to a cost surface derived from a raster: First read in the raster of the river map. In my case this has ...
  • 55.8k
2 votes
Accepted

Does the mean of latitude and longitude make sense?

Generally stated, taking the mean of many measurements is the way towards higher confidence in the result. And if the measurements differ in their own reliability, a weighted mean is in order. It is ...
  • 8,724
2 votes

Live Tracking with Garmin inReach explorer+

As far as I can see from using my Inreach, and some knowledge of the history, the "Garmin" Inreach product line was purchased from DeLorme, and although the device has been rebadged, the software ...
  • 55
2 votes

How to split a GPX track file into several files of N trackpoints each?

Thanks for the script! It's useful to me as well because my Garmin bike navigator starts to throw trackpoints away after a certain number of trackpoints is reached. I added a separation of waypoints ...
2 votes

Where to find a someone for QGIS custom programming

You should probably look towards The Open Source Geospatial Foundation (osgeo.org) and specifically in the UK, the UK chapter: https://uk.osgeo.org/ I thought the UK OSGeo web site had a list of ...
  • 55.8k
2 votes
Accepted

Where to find a someone for QGIS custom programming

On the QGIS website there is a page on Commercial support that state : Are you looking for a developer to add features you need or fix bugs you encounter? Here is an alphabetical list, divided in ...
  • 12.7k
1 vote

How to track progress on a route?

I would try with a python library called Shapely. After you import topologies into Shapely geometry you will be able to create MultiPoint(collection of Points) geometry along the line at the specific ...
  • 430
1 vote

Visualize Polygon Changes

If the changes are not too extensive, the Symmetrical Difference tool can help you quickly identify differences. The results are polygons representing areas covered by one shapefile or the other, but ...
  • 8,208
1 vote

convert geoJson data to interactive map tiles containing icons,labels and popups

I think what you are looking for is Vector Tiles. For example GeoServer offers this functionality with a plugin. Look into this tutorial: http://docs.geoserver.org/latest/en/user/extensions/...
  • 1,044
1 vote

Can I use avaraging to pinpoint the exact location of a stationary GPS device?

I've followed FelixIP's suggestion to use Convex Hull Peeling. Since the example in the linked post is written in R, I post here the corresponding method in Python. It's extremely simple since the ...
  • 111
1 vote

Finding out if I've deviated from given route too much (computing similarity between routes)

There are two functions in the PolyUtil class in the android-maps-utils library that might help. PolyUtil.isLocationOnPath() - Computes whether the given point lies on or near a polyline, within a ...
  • 1,525
1 vote
Accepted

How to adjust the Record Dates field in ArcGIS 10.3.1 for Desktop?

To change from UTC to database time you'll need to disable Editor Tracking, then re-enable it, choosing database time rather than UTC. Using the similar process as in your other question - ...
  • 29.3k
1 vote

How can I match Geolife traces using TrackMatching or similar tools?

If you want to use TrackMatching, you hav e to convert your input files to one of their supported formats https://mapmatching.3scale.net/fileformats The custom CSV/Text format has the following ...
  • 82.9k
1 vote

Keep only the last marker when geolocating

One thing you need to do is move the creation of the "Myposition" layer out of the callback and into an initialization function (possibly as part of startWatch() as long as you remove the layer in ...

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