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In search of a usable map service

7 August 2014
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Reading time: 4 minutes

Criteria for choosing a web map provider

In my previous article I defined the basics of a web map service provider. In this article I will discuss the criteria for choosing the right web map provider.

There are many good articles about comparing the technical features of the web map providers. I am specially interested in what I should know about an application before I start using the map, or even before I start reading comparitive articles of the web map providers. I did not find an article discussing purely the characteristics of the application where the map will be used, because there is no single answer. So I decided to summarize the criterias I use, when choosing a map service.

There are two terms which I use throughout the post, “web map provider” and “web map api”.  To clarify the difference, here a short description of both:

Web map provider
Web map providers offers a service, from where a map or layers can be loaded. It does not necessary contain a user interface, it can also be a rest service. Examples of providers are Google, Bing, ArcGIS Server and non-commercial Open Street Map.

Web map api

Web map api loads a list of layers from web map providers and visualizes them. Most of them are provided as JavaScript, but there are also native apis. Examples of web map api providers are Google, Bing, ArcGIS JavaScript and non-commercial OpenLayers and Leaflet.

Data

Before analyzing the map providers, I usually analyze the data I want to use.

Quality and Type

When I choose the external data to use, I consider type and quality of the data:

  1. I choose if I want to use tiled data for a background or vector data for performing queries.
  2. I check who is producer of the data and how often it will be updated. For example, data in OpenStreetMap is updated often by user contributions; commercial web map providers get their data from GIS data Providers.

As soon as I know which data I want to use, I need to know:

  1. In which format it is and to where it should be stored.
  2. Which is the amount of the data to use and how often it will be used.

Format

Most of the web map providers support the usual data formats like KLM and GeoRSS. Recently also GeoJSON has become popular. I need to know, if my data needs to be geocoded, or if all my data and external data must have the same spatial reference. Geocoding means converting addresses to coordinates. Performing geocoding or data projection at runtime can cost time and transactions. Currently OpenStreetMap supports the most variety of the data formats. Most of the web map apis can also read the formats of the other data Providers: for example Esri JavaScript which can read google fusion tables as well.

Data storage

Data can be stored locally or in the cloud. Most of the commercial web map offer to store the maps in their cloud. If you think about storing data in the cloud, it is important to check if the license has terms for the amount of data and the ownership of the data. If the data is already stored, sometimes the storage gives a hint of the most suitable web map provider. For example, Bing Maps supports SQL Server as web map source, whereas  ArcGIS JavaScript works well with ArcGIS Online and ArcGIS server.

Usage of data

Ideal is, if you define early the maximum data to show, because web map providers limit the amount and increase the costs, if the limits are exceeded. The amount of data affects naturally also the performance of the application. An example of a limit is a selection. Usually when selecting hundreds of elements, every web map provider is at its limits. A solution could be revisiting the business case of simultaneous selection or implementing alternative, a more informative and more performant way of showing the selection.

Usage of application

In addition to the aspect of the data volume, the usage of the application is as important. It is good to analyze frequency of the usage, environment of the usage and the need for “out of the box” services and integration.

Frequency

I recommend to know the amount of expected users and frequency of the usage. This helps to analyze the transaction and performance requirements. This amount is needed if you are evaluating a commercial web map provider. Also the domain of the application, may it be free, public, private or intranet, will affect to the cost of using commercial web map provider. OpenStreetMap is an exception; it can be used without costs.

Environment

If you want to use the application or the data offline, some providers are more recommended than others:

  • ArcGIS and Bing offer offline usage only via native interfaces.
  • Google offers limited usage via premium license.
  • Open Street Map is an exception as well; it is even possible to download the map data and host it on own premises.
  • Layers from commercial providers can be shown in OpenLayers web api, but then the license of the commercial web map provider is still valid.

Services and integration

Different web map providers have a different focus. Open Streep map is concentrating on being a traditional map data provider. Additional services like routing and geocoding are provided by third parties. Commercial providers are providing different kind of services, for example traditional Gis data analysis from Esri or Street map from google. When choosing a data provider it is good to recognize if services like routing or elevation will be used now or in the near future, or if there is a need for integration like for example office or 3D.

Development

If the decision of the web map provider is not clear after evaluating the requirements for the data and usage, there are also useful criteria for web map api. I find the criteria from Papa John for a third party library also applicable for web map service provider.

I find ideal, when the focus of the web map provider matches to the requirements. In that case I can be sure that my favorite service wont obsolete soon. Please notice that some of the most innovative and new services are considered as experimental and that they still can change or become obsolete. The stability of the api is important, in this area the commercial apis score is better than OpenLayer. A good documentation and activity of the community are also helpful for the developer. Google maps is in this area my favorite.

If you ask me which web map provider and web map api I would use, I would give you the typical consultant answer: “It depends”. But I hope that I gave you a few inputs in this article, so you know on what it depends. I like to hear your comments about what you find important when choosing an external framework, no matter if this is a web map provider or something else.

Comments (2)

Avatar

Beau Moore

30 July 2015 at 21:34

Quick question, do you mean KML or is there another geo-spatial file format called KLM? I Googled around and could not find any references to a KLM.

Anyway, good article. Thank you.

    Riina Pakarinen

    Riina Pakarinen

    31 July 2015 at 08:06

    Hello Beau,
    thanks for your message and correction. KML is the correct format.
    Cheers, Riina

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