I am trying to display the movement of vehicles that have GPS trackers on them in QGIS. I have a CSV file of the data that looks like so:
Vehicle points
I import the CSV file into QGIS saved as a SHP and put in the necessary information into the Time Manager plugin in QGIS, but when I hit the play botton on the Time Manager all my points just disappear even though it shows it as playing through.
I've checked my date formats and they are correct as QGIS should take them as: yyyy/m/d HH:mm:ss
Any ideas or advice would be much appreciated.
I found the issue, there was a start lat and long and an end lat and long for each point. I had to set the end lat and long in the start lat and long for the next proceeding point for the a particular points vehicle ID. Doing this allowed me to track a vehicles movement.
Related
I'm new to OSM and would like to know if my approach for finding the next intersection ahead is possible when doing it offline.
The goal is to get the coordinates (latitude/longitude) of the next intersection on the street I'm currently driving on. For that I have my actual position (lat/lon coordinates) and heading (w.r.t. the north-pole) at disposition.
My current approach right now is to first use my coordinates for getting the name of the street/way/trace in which I am driving; then use that name for knowing which are the next intersections on that street (to both sides); and then use the heading for knowing which direction is the one I should pay attention to.
Once I have the intersection, I would get its coordinates and continue with the program.
My questions are then, is it possible to do all of that offline, i.e. with a .osm file (or similar)?
And, do you know a better approach for getting the coordinates of the next intersection ahead?
Thanks a lot in advance!
PS. I was able to get the name of the street by using nominatim and to get all the intersections of a street by using Overpass turbo, but this solutions would need internet; or is there a way of using them offline?
I'm an R Programmer but I found that Qgis is better for some geo projects. I'm having a tough time with something and I've searched. Basically, I want to create a buffer around 5 points so that I can then sum the population for the buffer area. The issue I'm having is that the Buffer dropdown is not in my Geo Processing Tools. Rather I have a Fixed Buffer (QGIS v2.18.14 mac). When I use the fixed buffer I get a gigantic circle that takes up the whole map. Any ideas where I might be going wrong?
Most Probably your SRID of points is 4326, which is degree, minutes, seconds . You should convert the points to meter based SRID, say 3857. Then apply buffer in meters unit. Afterwards you can convert back your points to 4326.
I'm in the process of creating my first iPhone app. It is an exercise log that will allow users to use the GPS to track a run, then be able to save a map of the route as well as the time/distance and upload it to a website. A local list of runs would also be saved on the device. My question is, what is the best way to implement the saving and retrieval of the map? I recall reading somewhere that the way to do it is to have entities that have latitude and longitude attributes, and then fetch these in reverse by time when plotting the map. This would mean that each entity is a point during the run. Is there a way to store all of the coordinates in an array in one entity so that one entity would represent a whole run?
I haven't really looked at relationships since I'm new to app development, but it seems like I could use relationships to store runs? As in, have the parent entity be the run, and have one of the destinations be all the coordinate entities of that run. Does this sound correct?
Thanks!
Having run as an entity makes sense. For the waypoints along the route, suggest a relationship with a 1-to-many cardinality (that is, one run has many waypoints). The attributes of the run might include start time/date, end time/date. The waypoints attributes might be latitude, longitude, altitude, date/time. You'll probably want to experiment with how you decide to log a waypoint during the run. Maybe collect every minute, or based on moving a certain distance from the last waypoint.
The waypoint with the earliest date/time is the starting point, and the waypoint with the latest date/time is the ending point.
With the above, you can plot the route one a map, calculate speed between waypoints, average speed, total distance, and maybe some sort of difficulty factor based on altitude changes.
What's the easiest way to plot location track based on series of reading of accelerometer/gyro/compass sensors taken over time? Let's say I have following data taken every second:
ElapsedTime(s) xMag(uT) yMag(uT) zMag(uT) xAccel(g) yAccel(g) zAccel(g) xRate(rad/sec) yRate(rad/sec) zRate(rad/sec) roll(rad) pitch(rad) yaw(rad)
...
Is there an easy way to draw a location plot for any given time? I'm using iPhone 4 with xSensor app to capture data, but can't just use GPS. I would appreciate any hints. Both standalone applications and Java libraries would be good.
Double integration of the acceleration vector (after gyro & compass direction correction) will give you a location from some initial or arbitrary offset. The problem is that any small offset or errors in the acceleration data, which there will be, will result in a rapidly diverging position.
What might be more possible is to get frequent and precise GPS position data, and use the acceleration data to estimate the route in between two very nearby GPS fixes.
I'd like to know (from a high level view) what would be required to take a pdf floor plan of a building and determine where exactly you are on that floor plan using GPS coordinates? In addition to location, the user would be presented with a "turn by turn" directions to another point on the map, navigating down hallways, between cubicles, etc.
Use case: an iPhone app that determined a user's location and guided them to a conference room or person's office in the building.
I realize that this is by no means trivial, but any help is appreciated. Thanks!
It's an interesting problem. When you're using Core Location, you're not necessarily using GPS. Using WiFi and cell tower triangulation, you can get pretty good location results. So from Core Location you get a latitude and longitude fix. (You might also get altitude info, since GPS data is 3-dimensional. You also will get an accuracy value.)
So you have lat and lon. You need to map these coordinates to the PDF plan's coordinates. Assuming that the plan is aligned with the latitude and longitude lines, and that you have a lat-long fix for one of the points on the plan, you need to calculate the x-axis scale and y-axis scale. Then it's some calculations to map the lat-long to x-y coordinates on the PDF plan.
GPS may not be accurate enough for this purpose, especially indoors. Assuming errors on
the order of 10 meters, you'll have difficulty determining which floor the user is on.
Here's a neat (?) idea that might work: can you post some "You are here" placards
at various locations around the building? You could label each one with a unique,
machine-readable location code (maybe a QR code or something similar), then take an
image using the camera, have your app read that image and interpret the location code,
and use that instead of GPS to determine the start location.
GPS inside? That's your first -- and biggest -- hurdle.
Next hurdle is knowing the GPS coordinates of at least three points on that PDF to define the plane of of your map in the real world. (The PDF will need to be to scale, of course.)
So that gives you where you are on the PDF. Now you'll need to figure out some way to determine where you can walk (or where you can't) to get directions.