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Questions tagged [geolocation]

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

36
votes
3answers
31k views

Best GIS system for high performance web application - PostGIS vs MongoDB

I am working on a web/mobile application based on location data. Since i am already familiar with MongoDB, i found the geospatial indexing of mongo is quite suitable for my needs. As i am mainly ...
28
votes
8answers
60k views

Generating random locations nearby?

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 ...
27
votes
2answers
23k 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 ...
22
votes
2answers
7k 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 ...
21
votes
8answers
47k views

Seeking Country/State/City Database?

I am creating a directory which uses locations to categorize all listings. Instead of relying on user input, I'd like to provide a list of locations which the user can select. I have already tried ...
19
votes
8answers
23k views

How can I determine the location of a visitor to my website?

If I want to provide a website with location appropriate content, what ways can I use to find the visitor's rough location using their IP or header information?
19
votes
1answer
626 views

Why are geolocations on Twitter “rounded”?

I'm plotting some geolocations (lon, lat) of tweets collected using the Stream API with a 7mi. radius. The picture below shows two maps of the same data, but using different alpha/transparency for ...
16
votes
6answers
4k views

What algorithm should I use for wifi geolocation?

School Pickup Use Case (update) It might be helpful to go into a more concrete use case instead of the original backyard example below. Local law enforcement has started cracking down on use text ...
14
votes
4answers
9k 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 ...
12
votes
2answers
1k views

Propose a new location for Watch Tower using Viewshed Analysis

I want to suggest location for new watch tower in a forest area, but i am confused , on what criteria i can propose a best location. If i am taking DEM , slope and distance from existing tower , then ...
10
votes
1answer
176 views

How To Understand Geological Directions?

I was reading a "Guide to Some Minerals and Rocks in Indiana," which was published in the 1950s, and in it there were these bewildering directions: "Bluff along Mud Pine Creek 1.5 miles west of ...
10
votes
2answers
122 views

Where does one ask “Where is …?”?

On a fairly regular basis at my place of work we get inquiries of the form "where is Lake Potato?" or "where is Poppingstone Creek?" or... The questions come from co-workers, the general public and ...
8
votes
10answers
4k 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 ...
8
votes
2answers
1k views

What does the U mean in UTM=(32, 'U')?

I've come across code which specifies UTM=(32, 'U'). Is there a common convention around UTM I can understand this through, or is there not enough information here to determine the geographic location?...
8
votes
3answers
3k views

Seeking GPS device for vehicle tracking? [closed]

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 ...
8
votes
4answers
8k views

How does WiFiSLAM work?

Apple recently acquired WifiSlam. How does their technology work? Their website doesn't go into much detail. Allow your smartphone to pinpoint its location (and the location of your friends) in ...
8
votes
4answers
3k views

Geolocation database of beaches

Anyone know where or how to obtain a database of worldwide beaches? Required fields are: name latitude longitude coastline aspect (if possible) Alternatively, is there a way to query Google Maps to ...
7
votes
2answers
381 views

Is there a GIS to locate exact opposite locations on earth?

I was wandering if there was a GIS that offers to locate the exact opposite location of key locations (countries, even cities ?) on earth ?
7
votes
6answers
7k views

Using GTFS data to create Transit Route?

I am brand new to the General Transit Feed Specification (GTFS) stack and subway calculations and I'm working on a project where I need to tell a user what the best route / line to take based on their ...
7
votes
2answers
4k views

Does iOS know the phone's location solely from cell tower, i.e. without GPS data?

Question Does the iOS operating system know the phone's location even if one could turn off the iPhone's built-in GPS module or if it was broken? Elaboration What I understand I understand that ...
7
votes
5answers
454 views

What technique is used to acquire client location?

So far I know how to grab the client location to a application or web application by using the users geolocation or GPS location. I remember the possibility of finding the users approximate location ...
7
votes
2answers
1k 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 ...
7
votes
0answers
4k views

Downloadable, Open Source, IP GeoLocation database

I have an open source project I need a similarly open source IP GeoLocation database for. i.e. IP address to country (and ideally city). Ideally with a license that allows redistribution. This is a ...
6
votes
1answer
121 views

Figuring out the most probable country out of a string?

I got a problem with a twitter analysis i am doing. What i want to do: Based on the country i want to make a nice graphic about how many tweets were posted per country. Using python and tweepy i ...
6
votes
1answer
3k views

Checking if a geocoordinate point is land or ocean?

I got the corner geo coordinates from a xml product file of a Sentinel-1 GRD SAR image. When looping through the pixels of the image I wish to check whether it represents land or sea. I figured I ...
6
votes
1answer
108 views

Dividing the world space to geographic sub-space

I am trying to divide the world space to geographic sub-space from "general" to "specific" locations and without using latitude and longitude information. That is, I am trying to think about the world ...
6
votes
1answer
4k views

Where can I find High Quality Road Network Information

I am carrying out a research on how complex city road networks get and I need to get accurate map information. I started with openstreetmaps however I ran into a couple of issues: some of the dumps ...
6
votes
0answers
686 views

Translate Orientation from Sensor data to Geo location

I am tracking a device that might loose GPS signal then and there. And when the GPS signal is too low, I should use the accelerometer and Gyroscope sensors data to guess which way they should have ...
5
votes
2answers
413 views

Changing the geolocation of a point in the map

I uploaded a vector layer with points = cities. After zooming in I found out that some cities are on wrong places. How can I change the geolocation for a specific point, city?
5
votes
0answers
73 views

Calculating centre of city? [closed]

A lot of career websites allow you to select jobs from within a radius of your chosen location. Since cities and towns can be considered irregular in shape, sprawling in the definition (do you ...
4
votes
2answers
3k 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 ...
4
votes
1answer
342 views

Converting Australian coordinates (EPSG:3112) for mapping in R

I'm trying to map road accidents in Australia, which comes with x and y coordinates (e.g., x = 1328459.1 and y = 1670878 for Adelaide) as well as the following information: PROJECTION LAMBERT UNITS ...
4
votes
1answer
2k views

What is the best database for an online Android location app?

I am working on Android app for locating food places in my city. Using Google Map v2 api. App shows user his current location, and the closest food spots around him. I want to store location ...
4
votes
3answers
369 views

EPSG geotiff code and crs us48

I am trying to create a geotiff and the software (raster design) is asking for a code that I thought was EPSG code. however while trying to find out what epsg = us48 I noticed that the dialog actually ...
4
votes
1answer
229 views

Using Gazetteers to mine locations from text

I am starting to work with Gazetteers and trying to find something that will actually "mine" geospatial locations from sets of text. Academically, this is a difficult task as texts are based on ...
4
votes
1answer
863 views

HTML5 Geolocation with ArcGIS for JavaScript API?

My organization would prefer to use its own basemaps rather than those provided by ArcGIS Online due to the accuracy of information that is represented in them. The area we service is rapidly ...
4
votes
1answer
2k views

Probability of iOS/Android device location accuracy

I'm working with Android and iOS apps that report location. Both iOS and Android can derive location from a combination of cell tower triangulation, visible wifi access points, and assisted GPS. The ...
4
votes
1answer
136 views

Looking for HowTos or Examples of Presentation Platforms targeting Management/Clients

Any good ideas about using Google Earth to present self contained geospatial data&app to a client or senior management? The broader issue being explored here is that many of our clients are not ...
4
votes
1answer
552 views

extracting geographic location from NOAA NARR grib

I've downloaded a NOAA NARR grib file that I want to extract the wind component as well as the geographic location. I'm able to extract the wind component from the grib but I can't seem to find any ...
4
votes
1answer
332 views

Create Archimedean spiral with geographic coordinates

I don't know if this is the right place to ask but here it his. I want to create an Archimedean spiral based in some location. Lets say I have this set of geographic coordinates (48.860770, 2.337655)....
3
votes
2answers
5k views

Socket Server to receive GPS location data

I am working on a web application which receives data sent from trackers via TCP Packets containing location information. Up until this point we have been working with dummy data within the mysql ...
3
votes
1answer
225 views

Worldwide places reachable by sea/ocean

I'm looking for a list of all populated places(not just big cities/ports) on the world that reside on sea/ocean. The list should contain the place name, latitude and longitude. Does something like ...
3
votes
3answers
411 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 ...
3
votes
1answer
657 views

Improve leaflet location interval

I'm using leaflet 1.0.3 with latest plugin leaflet-locatecontrol. When I start to locate myself, it takes arround 5 seconds. My position is being watched constantly and even if I move right after the ...
3
votes
4answers
7k views

Difference between Positioning and Localization

I would like to know what are the differences between Positioning and Localization. In most papers they are used interchangeably. Are they the same? Does one come after another? I always thought ...
3
votes
2answers
1k views

Reading MODIS L1B into ENVI

I am working with MODIS Terra (and simultaneous ASTER) Level 1B swath data using ENVI and am having one of these "this should be easy" questions about the most direct way to get to geo-referenced ...
3
votes
1answer
1k views

Masking land with matplotlib basemap in Python?

I've been trying to mask land with .is_land from mpl_toolkits.basemap. When running following code: map = Basemap(llcrnrlon = 7.298914095230308, llcrnrlat = 58.98235690451632, urcrnrlon =...
3
votes
1answer
416 views

Attribute table of a point: longitude, latitude info missing

In my QGIS map I have several vector layers. They all appears on the map well. I am just wondering, where in the Attribute table I can find the information about the geolocation. I supposed that in a ...
3
votes
2answers
2k views

Move leaflet polygon to given position

I have a circle and a polygon that I'd like to move to the user's local position. I managed to move the circle latLng but I can't find a way to do the same thing with a polygon. Can someone help me ...
3
votes
2answers
147 views

Where can I find a map with the location of towns and cities in Southern Sudan?

For a project I have some name of towns and cities in the Southern part of Sudan, the region South Kordofan. Many of these towns I can't find on Google Maps, but I need to know their location. ...