Using OneMap in iOS map application

I am learning Swift, the new programming language developed by Apple for iOS and OSX application development, and ArcGIS iOS SDK. I am planning  to make a series of tutorials based on what I have learned progressively.

In this tutorial, I am going to show you how to use Singapore’s official map platform, OneMap (, in iOS 8 application.

OneMap is an integrated map system for government agencies to deliver location-based services and information. It is a multi-agency collaboration with many government agencies currently participating and contributing information. ~

To use OneMap in our iOS app, we need to use ArcGIS iOS SDK from Esri.  First download the ArcGIS SDK for iOS from Follow the guide to install and setup the development environment. ArcGIS has a very comprehensive guide for installing and setting up the development environment.

To use OneMap, first you need to add a UIView to your storyboard. In the Identity Inspector, change the UIView class name to AGCMapView.


Connect the map view to the view controller by creating an outlet in in ViewController.swift file.


Import the ArcGIS framework in view controller’s swift file to use ArcGIS SDK for ios.

In the viewDidLoad method of ViewController.swift file, create a tiled map layer using OneMap map service and add it to the map:

Run the application and you will see the map application displaying base map in the map view.

Initial Run

Right now, our map displays the whole Singapore, but we want it to be focus on a particular area in Singapore when it is loaded. To do this we need to define the initial map extent to zoom in display. We need to pass the envelope geometry to the  zoomToEnvelope:animated: method to zoom to the area we are interested in. 

An envelope is defined by a pair of X-Y coordinates representing the lower-left and upper-right corners of a rectangular bounding-box.

To create an envelope geometry, we need X min, Y min, X max and Y max. How do we find out this values? Pretty easy. We can get the current map’s extent from mapView.visibleAreaEnvelope property. So we just have to zoom in to the area of interest and inspect the current mapView.visibleAreaEnvelope values and use them as the initial extent in viewDidLoad method.

Our View Controller must adapt to the  AGSMapViewLayerDelegate protocol and set itself as the delegate of mapView‘s layerDelegate.

In the viewDidLoad method, add this line to set delegate. See the API reference documentation for the AGSMapViewLayerDelegate protocol to learn more on layerDelegate

Then implement mapViewDidLoad delegate method to add observer for mapView pan and zoom notifications.

Run the application and zoom to the area you want to show on initial start up. As you zoom in to the area, you can see then envelope geometry data printed out in Xcode console. When you are satisfied with the view, copy the X min, Y min, X max and Y max from the console and use them as initial extent.

I choose Nanyang Polytechnic as my starting view and create an envelop geometry from it. Following is the complete code:

Mat on NYP

In this tutorial, we have learned how to add OneMap as based map to the iOS application and setting up initial map extent to the location of interest by using envelop geometry. If you want to know more about OneMap features and services, please visit to their API help page

Look forward for more tutorials on using OneMap from me and please leave a comment if you find any error or have difficulty following the steps above.

Batch Geocoding Tool For Singapore SVY21 Coordinate System

I have created a tool to geocode large amount Singapore postal codes into X, Y values of SVY21 coordinate system. SVY21 is the Singapore standard coordinate system used by Singapore Land Authority.

You can get the X, Y values of an address by using search function provided in But if you have a few thousands of addresses to geocode, my batch geocoding tool can help you better. You need internet connection to use the tool because the program is the wrapper written in c# to call web service provided by onemap.

Download link:  Batch Geocoder Installer 

Download the installer and unzip the folder. Run setup to install the tool on your computer. You may need .NET runtime to run the program. After installation run the tool from start menu.


Simply provide an input file containing a column of Singapore postal codes. Give the name and location of the output file where the result (X, Y) values are to be written. Click Run button to start the batch process. It may take a while depending on the number of postal codes you are processing.

Right now, the tool can only accept postal codes as input. In the future, I am planning to extend it to accept whole or partial addresses as input. The source code is hosted on Github for anyone who is interested to look at it.