Last week I introduced the open source application QGIS, which gives all of us free access to powerful geographic software and liberates the more casual users among us from dependence on the commercial mapping suite for Windows, ArcGIS.
In this posting and the next, however, I want to introduce some online services which are starting to bridge the gap between the capabilities of Google Maps or Google Earth, and the more powerful but complex spatial analysis tools out there, at least when it comes to collecting, displaying, and sharing rich geographic data.
The first of these is the new WorldMap platform developed at the Center for Geographic Analysis (CGA) at Harvard University. The WorldMap platform makes it extremely easy for new users to get up and running with her own collection of geographic layers. After signing up for the service you can begin creating your own maps immediately and add in multiple geographic layers from a range of sources, including the library of layers other users of WorldMap have uploaded, an external layer accessible through online geographic resources (such as a WMS server or an ArgGIS REST server), or directly uploaded by you in the supported formats (Shapefiles and geotiffs) that are popular with many online geographic resources. You can also create your own layers in the interface, but I found it somewhat involved, and I suspect it is easier to create your own layers in an application like QGIS or even use a conversion utility on a simple layer you made in Google Maps, which outputs its own format, KML.
Once you have added a set of layers to your map you can easily share either the default view the map or any specific zoom (Tip: shift-click to zoom to a particular area), base map (Google or OpenStreetMap), layer selection, and layer opacity through its “link” tab. This also allows you to directly embed a particular map view in a small iframe within, for example, a blog posting. Depending on your permission configuration for the layers, visitors can also download data sets associated with layers directly through the platform.
One example of a powerful use of this platform is the JapanMap collection of layers for a project I have been working on over the past year. The layers were assembled and curated by our GIS specialist Ray Kameda and by Lex Burman at the CGA from a wide variety of publicly available geocoded data or from data assembled by volunteers and shared with the Japan Sendai Earthquake Data Portal. The WorldMap platform made it extremely easy for our project to offer visitors a way to browse through a very large and varied collection of geographic data, while supporting the ability to inspect individual elements, display a legend, and download data layers.
Of course, there are some things for which Google maps or Google Earth are sufficient or even better, depending on your needs. Also, as GIS professionals will be sure to remind you, these various tools don’t let you do any spatial analysis. For that, there is QGIS and—if your institution is generous with its licenses and you use Windows—ArcGIS . However, I can think of lots of ways to make use of the WorldMap platform in, for example, a classroom environment. When we have assembled a collection of useful data layers related to a given topic, students can gain much from having access to a collection of map layers for a course. WorldMap is by no means the only show in town, and I’ll introduce a few more next week, but I’m really impressed at the commitment of the CGA team to building upon and expanding open source GIS tools and offering to host WorldMap and its growing library of layers for us all.
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