# Tagged Questions

Geolocation is a means to discovering the physical location (in real-world geographic terms) of an object.

13k views

### Trilateration algorithm for n amount of points

I need to find algorithm that can calculate centroid A (aka gravity center, geometric center, center of mass) from the figure where circles T1,T2,T3,T4,T5,..,Tn intersect AND length of line R from ...
3k views

### Device for Logging GPS and Accelerometer Data? [closed]

I am looking for a device that can track my location (lat,long) and speed all day long. Perhaps, I need GPS and accelerometer data bundled together. What I want to do is to log my daily activities. I ...
24k views

### How to generate random locations nearby my location?

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. This is the formula i came up ...
4k views

### Calculating the distance between a point and a virtual line of two lat/lngs

Please refer to the example and corresponding image. I would like to achieve the following: provide two locations (lat/lng), which are shown below as A and B. From this, a virtual line would be drawn ...
4k views

### Calculate distance of point from an arc/polyline

Using Postgres/PostGIS, I am trying to query the database for the closest arc to a particular GPS point. Each Arc is made up of two nodes that are GPS points on a map. Is there a way I could query ...
26k views

### Is a Country/State/City Database available?

I asked this question Stack Overflow but I was informed that I would get a better to this question here because it's not related to programming. I am creating a directory which uses locations to ...
2k views

### How much sense does it make to average (lat,lon) samples in order to increase 2D accuracy of a GPS location?

Several GPS applications, like this one, or this one, acquire multiple (lat,lon) samples of a given location, assuming that the GPS unit is not moving, and then take an average of the samples in order ...
2k views

Where can I find some address locator styles for European countries? or how can I create my own address locator that contains street, house number and city, and use their aliases? PS. I have the ...
2k views

### Seeking GPS device for vehicle tracking?

I am a programmer with no connection to Geographic information, except that I work on application which uses Google Maps. I need some device, which I will be able to set in a vehicle in order to keep ...
611 views

### GPS and GIS for real time monitoring of an object

How is it possible to store coordinate of object in server in real time using feasible hardware ( can be used by student) GPS into database and retrived in real time?? What are the names of ...
971 views

### Open source location allocation modelling

I'm looking for open source tools for location allocation modelling (eg planning public health facilities). Preferably in a GIS environment. I know GRASS somewhat, but v.net.alloc doesn't seem to ...
258 views

### Display millions of points in the browser

I have a web application which will track he movement of user, and save the history location to database. And user may want to see his/her movement trace over a period of time, we have to display ...
2k views

### How to calculate midpoint given north/south latitude and east/west longitude?

First, sorry if this questions sound very simple. I am very new to GIS. Given four values of north/south latitude, east/west longitude how to calculate the center point that is correct for all cases ...
2k views

### Offline Python or C++ library for plotting locations on map?

I'd like to plot locations using longitude and latitude coordinates using Python or C++, is there a good library for such a task? I know that matplotlib is an option, I'm wondering if there are any ...