[YS Learn] Introduction to digital maps

This is part of an educational series on the LBS domain. Through this series, we will explore features of Maps and location based services, potential areas and opportunities and companies that operate in the domain.

Maps are a representation of different physical attributes of the real world.

Maps and map making have evolved over the ages. While maps were primarily used for exploration and navigation, digital maps now support a multitude of use cases, ranging from vehicle tracking, fleet management and geo-fencing to consumer use cases like discovering nearby places, finding friends’ locations, seeing where photos were taken, etc.

Technology has eased many of the pains of map-making, but building maps still requires sizeable investments. Challenges in map making are not only in building maps the first time, but also in keeping maps fresh. This is significant in emerging markets where many cities are rapidly changing.

Many of the larger map-makers also encourage user feedback, or crowdsourcing, to help gather information, and have mechanisms in place to vet the data before including it in their mapping databases.

Map making is a complex space, and recent missteps by Apple with maps on iOS6 have shown that even to large companies, getting the basics right can be a challenge.

Here’s more info on how Google and Nokia approach map-making.

In both cases, sophisticated technology and manual addition and vetting are used to keep maps fresh.

Basic features of digital map solutions

Most map solutions offer the following features. Many of these features are also exposed to 3^rd parties for use via APIs.

Map display - map data gathered is graphically rendered and displayed to the user or app. Map data can be rendered in online or offline modes and can be displayed in 2D or 3D modes. Data may also be displayed in richer formats like satellite view and street view.

Online  map data – The maps application or the 3^rd party using the API asks a map data server to deliver maps of a particular zoom level and location. Depending on this info, the server returns a set of image tiles (in png or jpg formats) that can be rendered on the device or laptop screen. Each tile has an associated zoom level and a location tag. All data is fetched from the server instead of being stored on the device.

Pros:

-             No map data is stored on the device. In devices with constrained onboard memory, this frees us space on the device for other storage purposes.

-             Map data updates are easier, as all data is stored on the server and is rendered only upon request.

-             For additional information, the server is able to ‘paint’ information onto map tiles and send them to the device (eg: to show traffic display on the map).

Cons:

-             A data connection is required for any action from the user – panning or zooming in or out from the map, route planning, all require the server to send fresh map tiles.

-             In markets where data plans are expensive or networks are choked, this may result in higher data costs or longer latencies before the user sees the map.

Offline  map data – In this form, map data is stored on the mobile device internal memory or on a memory card in a vector format. This is also called an onboard data approach.

Pros:

-             When the user pans/zooms in or out, the data is stored in a format that the map application can read and display the map information without a data connection, as all map data is stored locally.

-             Information required for planning routes, showing POIs, etc. are also stored offline, so a lot of the map functionality can be handled with minimal or no data requirements.

Traditional car navigation systems came embedded with offline map data as this form is most suited for navigation use cases.

Cons:

-             It is difficult to keep data fresh, a key concern when map data keeps changing. The user has to either refresh all map data onboard, or download parts of the map data, if supported.

-             This involves a significant amount of data transfer, and is usually advised when the device is connected to Wi-Fi.

-             This approach also means that a lot of onboard memory on the device is dedicated to store map data. If the user downloads maps for many countries (say to drive around Europe), then the data requirements quickly add up.

2D  and 3D modes – If map data is offline (onboard map data), the maps application could choose to display the same data in 2D or 3D modes. In 3D modes, maps display other topographical details like building heights, 3D city view, etc. to let users have a virtual feel of the city.

3D modes are also supported with online map data, but a different set of map tiles need to be downloaded to display 3D modes. This usually results in heavier data transfers.

 Satellite view – This is a special mode that allows the user to see an Ariel view stitched from satellite photographs. A data connection is required for this view.

 Street view - Map providers like Google and Bing also provide a street side view of a place, by collating photos of the actual location. This is an online only function.

In the next article, we'll walk through some of the common functionality of maps.

The author can be reached at [email protected] or at @shrinathv.