New answers tagged

0

If you are editing a shape file made up of polygons, you cannot add a point to it. If you are logging track points along a line you wish to collect, you need to add the line when you are finished logging the tracking points. Shape files are restricted to a specific, and single vector type for each layer. Points Lines Polygons You cannot mix, and match them. ...


0

I try to keep my desktop projects separate from my field data during data collection, and only go back to my desktop for processing and analysis. I will advice you to get your geometric points on the field and extract them into Qgis as a new layer and move on smoothly.


0

NextGIS Mobile http://nextgis.ru/en/nextgis-mobile/ NextGIS Mobile is an open-source mobile GIS for Android which allows to create, edit and export geodata both online and offline. NextGIS Mobile allows to: show multi-layer map (layers can come from online and offline sources); change visibility and layers order; navigate the map (panning, zoom in, ...


0

Android devices and apps supporting Galileo positioning are bound to arise and become more popular as Galileo itself starts to operate in full gear, with the whole array of satellites having been deployed. In that respect, yesterday's launch by the European Space agency of satellites 13 and 14 in the Gallileo constellation mark a significant step ...


0

I've used a GiSTEQ PhotoTrackr Mini, which is a slightly oversized USB stick. It creates and stores track logs, primarily for geocoding photos. It has good battery life and charges via USB, however I don't believe it records precision information as you require for point 3.


-1

There's a market for GPS loggers that are placed into packages or shipping cartons and left on while the item is in transit - that way the recipient can review the path the package took to get to its destination. You might be able to use one of those. Best example I could find is from this company: www.keskull.com (I'm not certain these are precisely what ...


-2

Because satellites are not in 'space", but only devices that are mounted high up on man built towers... with the highest altitude possible. They use 4 devices to construct a square space around you and from that they calculate your coordinates via computation of that built square. When they do land confiscation, they measure the distance between the built ...


3

If you know the exact position of the receiver then it is possible to do timing with only one satellite. Essentially GPS is solving four unknowns (ECEF position, and receiver clock error) with four (pseudo-range) distance measurements, so if you can provide three unknowns, you only need one measurement. Not all receivers support this though - it was a ...


0

Precision of a GPS device depends on how it evaluates the position. A-GPS(Assisted Global Positioning System) Devices : Usually mobile phones. Uses cellular network as well as satellites to triangulate current position. Some Devices even show you altitude with latitude and longitude. GPS (Global Positioning System) Devices: Usually proprietary ...


4

If it's possible, use your GPS unit to get position & elevation of a known benchmark and then compare that with the official values. Here is a picture of a USGS benchmark. If you can't find the locations of any near you, just contact your USGS local office. If you cannot access benchmarks, see if there is some structure that you can get precise ...


0

I don't know why this actually works now, maybe someone could explain it, but after many tries I succeded by using the following code: SELECT AddGeometryColumn ('vehicle_2015_02','projected_point',4326,'POINT',2, false); UPDATE vehicle_2015_02 v02 SET projected_point = ST_LineInterpolatePoint(romo2015_way.st_makeline, ...


0

You may need to rewrite your UPDATE statement, using an explicit join. UPDATE vehicle_2015_02 v02 SET projected_point = q.newpoint FROM ( SELECT vehicle_2015_02.objectid, ST_LineInterpolatePoint( romo2015_way.st_makeline, ST_LineLocatePoint( romo2015_way.st_makeline, ...


0

If you export the line (presumably shapefile) to a geodatabase, the Shape_Length field is added automatically and dynamically maintained (splitting, merging, etc. will work) To calculate a static length, use the Calculate Geometry tool in the attribute table. Right click on the column you wish the calculate -> Calculate Geometry. This is a static ...


1

From my experience at a place where I used to work, they used a company that placed GPS units with cellular modems that were also attached to other vehicle sensors. The unit was programmed to send its location and sensor information over the cellular network to the company's server every 5 minutes I believe. The reason this was done is because they charged ...


0

IT is indeed done by cellular network, the gps device came gprs enabled which consistently send data to the configured server port which has listner program consistently running which then receive,parse and store data to database which can then be use to show live data or history of vehicle, and when there is no network availability data is cached by gps ...


0

As @user30184 suggested, it's not a standard. Apparently, it's a mix of $GPRMC and a Tetra location message.



Top 50 recent answers are included