GIS/GPS Programming

The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides reliable location and time information in all weather and at all times and anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more GPS satellites. A geographic information system (GIS) or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location(s). In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology.

Share tech news, updates, or what's on your mind.

Sign up to Post

I am developing my first application with Apache Cordova and I need some assistanstance with the Open Street Map object. I am sending a request to the Open Street Map to get Lat/Lng of a location. I chose Manchester UK and I received the following JSON back:

In order to do this, I set to share a taxi (it's a taxi sharing app) first and then I click on Update Map.
This is the code for UpdateMap:

     function updateMap(address){
        var onSuccess = function(position) {
          var div = document.getElementById("map_canvas");
          div.width = window.innerWidth - 20;
          div.height = window.innerHeight * 0.8 - 40;
          // change the zoomin level
          if (address != undefined) {
            // TODO 2(a) FR2.2
            var endPoint = "" + address + "?format=json&countrycode=gb"
            $.get(endPoint,function(e) {[embed=file 1418190][embed=file 1418191][embed=file 1418192]
              var location = e;
                lng: location.lng,

          } else {
              lng: position.coords.longitude,
              lat: position.coords.latitude
        var onError = function(error) {
            "code: " + error.code + "\n" + "message:

Open in new window

Exploring SQL Server 2016: Fundamentals
LVL 13
Exploring SQL Server 2016: Fundamentals

Learn the fundamentals of Microsoft SQL Server, a relational database management system that stores and retrieves data when requested by other software applications.

Where can I find complete list and definations and all PGN who NMEA 2000 uses ?
The Point is      x=0.6160      y=0.8308
Determine coefficients of the equation for a second order polynomial in the format:
I browsing ESRI.COM website to try to understand the current GIS solution. I couldn't find where the instruction for ArcSDE (Spatial Data Engine) is.
Is the ArcSDE product being deprecated/retired? or it is just hiding some where?
Thank you!
Dear All,

I have a device (installed on vehicle) which sends latitude and longitude on the Server through GPS. I have a route of that vehicle which is successfully plotted on Google Map.

My Problem is how can I plot latitude and longitude at runtime on Google Map in PHP dynamically on Desktop Application. I want to plot fetched latest latitude and longitude on Google Map to show where the vehicle is running.
How to convert Polyline Z to normal polyline
I have successfully installed tilemill and styled my maps using OSMBRIGHT as the a starting point
I've edited this theme to get it the way i need, it looks great apart from one thing:

I when zoom out to the world, the style is pretty bland (just one colour)
I wanted to use something like google streets on full zoom out level,-55.8196685,4.18z

or like this

I've found something called natural earth 2 which also looks nice

My question is, how can i style OSM bright at max zoom out levels to look like the above?

I've been looking an it appears i need to apply GlobalLandCover layers like

I'm currently using Raster tiles

This is the base.mss that I was using as my starting point

Can someone give me the code to achieve the above please?
Can I replicate a search using the Google Maps API local search with  an iOS MKLocalSearchRequest() ?  For example, using the Google API, making a map search using the keyword "hostels" works correctly. In iOS using MKLocalSearchRequest(), using a naturalLanguageQuery, I just get hotels. Is there a way to fix this?  Or am i forced to use the Google Maps API within iOS?
Need SLQ (or other systematic way) to change XCOORD and YCOORD  into the  Latitude and Longitude GIS format.

Sample XCOORD: 2121551
Sample YCOORD: 19744813

Sample Latitude: 29.49252
Sample Longitude: -98.67554

I have  a data set of 500 000 rows and need to have a daily systematic way to have this done in SQL (preferably).
Where can I buy gps tracking device who will upload location to server at your own choose.
Amazon Web Services
LVL 13
Amazon Web Services

Are you thinking about creating an Amazon Web Services account for your business? Not sure where to start? In this course you’ll get an overview of the history of AWS and take a tour of their user interface.

Hi I need to find the distance between 2 pin codes. For that i would like to find the center point within each pincode and calculate distance between them. This is for my internship project. So how to find the center point within each pin code?
Employee Tracking - GPS - I want app to web solution for tracking my sales employee and location with form to be filed when they reach that location.

I need to calculate the Grid value based on lon/lat value of particular point  on map. The attached file display the "test_incident" point , need to calculate that point grid value.

Is there any formulas /algorithms  or any API to calculate the grid value.

I have a simple equation to calculate the "CL" from the sum of four different grids as:

CL = A + B + C + D

I am attempting to use the mc2d package with R to express uncertainty in the CL results based on uncertainties in each of the input grids.

The uncertainty in each input grid is expressed based on uniform distributions with uncertainty ranges of:

+/- 6 for raster A
+/- 10 for raster B
+/- 12 for raster C
+/- 5 for raster D

I would like to run a Monte Carlo simulation whereby the input grids are summed multiple times (e.g. n = 1000) based on values for each grid cell that are randomly selected from within these uncertainty ranges

The code below fails with:
Error in .calcTest(x[1:5], fun, na.rm, forcefun, forceapply) :
    cannot use this function

Any suggested edits?

library(mc2d) #load package

# Input grid files
A <- raster(matrix(c(20, 35, 40, 60), nrow=2))
B <- raster(matrix(c(6, 10, 13, 14), nrow=2))
C <- raster(matrix(c(6, 8, 12, 14), nrow=2))
D <- raster(matrix(c(35, 40, 50, 60), nrow=2))

# combine the RasterLayer objects into a RasterStack 
s <- stack(A, B, C, D)

# Uncertainty distance for each raster used to establish the 
# min/max for the uniform distributions in the function just below
uA <- 6
uB <- 10
uC <- 12
uD <- 5

# Function for generating CL
fun <- function(x) {
  # Convert each raster to mcnode object
  dA <- mcdata(x[1], type="0")
  dB <- mcdata(x[2], 

Open in new window

How can I have Google maps show markers for an input list of mailing addresses

I've got a GeoJSON file of administrative borders i.e. state and county, and a CSV file with 12,500+ named GPS coordinates located within the geographic area.

My boss wants me to use the GeoJSON identify the county for each GPS location so I end up with a CSV file (format) like;

Is there any tool that can do this?

Thanks a bunch.
With AS3 I combined geolocation and accelerometer to direct the iphone, with its back towards a star at the sky. Accelerometer works fine for tilt 0-90 degrees ( directed towards horizon, phone vertical - towards zenith, phone horizontal with screen downwards) but geolocation heading of course flips around 45 degrees tilt and begins to show star direction + 180 degrees. Around 45 degrees tilt geolocation heading becomes very random and I would be very grateful for a suggested algorithm to eliminate the randomness of this phase shift.
Specifically my problem is:

head = event.heading;
head2 = event.heading -180;
 if(head2<0){head2 +=360;}

 if(angleSky>45) {head3 = head2;} else {head3 = head} // angle obtained by accelerometer

Ideally above angleSky 45 the code should choose head3=head2 and that should then be a continuation of the heading below 45. But this is not the case. Sometimes the geolocation heading switches at 43 or 44. Thus what I have tried but not succeeded is to store head  at 42 or 43 and then compare head3 with that. If head3 then is more than 100 degrees difference I tried to use the heading at 42-43. But I have not succeeded. Can it be that the aquisition rate, 50 mS is too fast? Or is this attempt to solve the problem not the optimal model?
Dear Sir ,

I am working on a GIS Data creation application , I would like to have your need for customization .I want that when user open a ArcMap application It will ask for Login window and user need to put their credentials ,then it allow to go inside the ArcMap ,Where I have ArcGIS Service and after accessing these service user will start to digitize the features in both online and offline mode .

If user created the feature and he doesn't have any internet connection while digitizing the features then data store in local table and once internet connection is there it will automatically store in the central server .

I look forward your kind help

Thanks & Regards.

I have a problem in GIS coordinates. I have this excel file with unknown CRS

sample data:
source coordinate (EPSG:4994 PRS92)
x: 675282
y: 1217112
    - note (the location of this coordinate should point in Ormoc City, Philippines, because i know where this entity is located)

target coordinate (EPSG:4326 WGS 84)
Lon: 124.6051799°
Lat:  11.0016664°

but when you show it on the map, the coordinates points somewhere near the port area instead of pointing in corner real and burgos streets, Ormoc City, Philippines (should be near this coordinate LON=124.60670952, LAT=11.0056316)

I'm using this for the transformation. Do you have any formulas that i can write in my excel file to convert it properly? Thanks in advance.
Microsoft Azure 2017
LVL 13
Microsoft Azure 2017

Azure has a changed a lot since it was originally introduce by adding new services and features. Do you know everything you need to about Azure? This course will teach you about the Azure App Service, monitoring and application insights, DevOps, and Team Services.

Is there anyone here familiar with SKiaSharp or SKia (a search here found no mention of this software)?  Basically, I take the survey lines from a survey, and draw the outline of the land, using SkiaSharp\DrawPath.  This works fine for straight line surveys, but it cannot handle lines that are not straight.  I have posted in the Xamarin\Skiasharp forum..., but have not had any replies.  And, I cannot find any examples\samples on the subject.  If you think that I should be posting elsewhere, please point me in the right direction.

I'm looking to consolidate two google script functions into one:

functions are:
1. getLongLat - this looks up the Long & lat positions given an address
2. GetCityL2L1Country - this looks to city state county and country given long/lat

example Google sheet using these functions:

I want one function eg GetStructuredAddress() to return and array of all 6 items, ideally using as few requests as possible (as google limits free requests)

var geocoder = Maps.newGeocoder(),
    cache = CacheService.getScriptCache();

function GetCityL2L1Country(latitude, longitude) {
//  var latitude = 51.69048,
//      longitude = 5.29362,
  var cacheKey = latitude + "+" + longitude,
    cached = cache.get(cacheKey);
  if(cached !== null) {
    return JSON.parse(cached);

  var result = geocoder.reverseGeocode(latitude, longitude),
  //First response is the most specific
      response = result.results[0];
  if(response === undefined) {
    return "??";
  function g(fieldName) {
    for (var i = 0; i < response.address_components.length; i++) {
      if(response.address_components[i].types.indexOf(fieldName) != -1) {
        return response.address_components[i];
    return {"long_name": "??"};
   rValue = [[ g("locality").long_name, g("administrative_area_level_2").long_name,  g("administrative_area_level_1").long_name, 

Open in new window

I am working on GIS applications and found the slope algorith in the net :

attached is an example I used to apply the above algorithm for calculating slopes from a DEM. I am not good in math so I got two results.
Can you help me please . I got 73, -33, 56.648 and I do not how to do the arctan.
Below is an extract taking from a paper available at:

I need to understand it please very well. It is all clear until he starts the second paragraph.
The second paragraph mentioned an indicator I am not sure I understand the whole second paragraph.  Please help to clarify I am starting to study these models and their integration with GIS. Thanks

A model is a computer program that takes a digital representation of one or more aspects of the real world and transforms them to create a new representation. Models can be static, if the input and the output both correspond to the same point in time, or dynamic, if the output represents a later point in time than the input.

The common element in all of these models is the operation of the GIS in multiple stages, whether they be used to create complex indicators from input layers or to represent time steps in the operation of a dynamic process. Static models often take the form of indicators, combining various inputs to create a useful output. For example, the Universal Soil Loss Equation (USLE) combines layers of mapped information about slope, soil quality, agricultural practices, and other properties to estimate the amount of soil that will be lost to erosion from a unit area in a unit time (Wischmeier and Smith 1978). The DRASTIC model (fig. 1) estimates geographic variation in the vulnerability of groundwater to pollution, again based on a number of mapped properties
I am looking for a recommendation for a geocoding tool that will geocode street addresses. I have approximately 14k that I would like to batch code and of course I am looking for a free tool.

Any advice is appreciated.
I want to create a map application where the best possible route from a source to a destination will be marked for the user. The best route will be calculated based on what traffic markers (low, medium or heavy congestion) there are in junctions or intersections. The traffic markers will be imported from a database. How do I implement the best route using ArcGIS?

GIS/GPS Programming

The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides reliable location and time information in all weather and at all times and anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more GPS satellites. A geographic information system (GIS) or geospatial information system is any system that captures, stores, analyzes, manages, and presents data that are linked to location(s). In the simplest terms, GIS is the merging of cartography, statistical analysis, and database technology.

Top Experts In
GIS/GPS Programming