OpenScales – the open source Flex mapping API – is a nice change from development with the ArcGIS Flex API. I’ve been working for over a year now with OpenScales. You’ll find in this blog various mentions of the work I have been doing. I have had the opportunity to test in some depth the strengths, and weaknesses of this API. I’ve been approached recently with questions about OpenScales as an alternative to the ArcGIS API.
OpenScales – an alternative to the ArcGIS API?
So is Openscales a realistic alternative to ArcGIS? A year ago I would have said no. Today, with the continued code updates, my opinion has changed. The biggest weakness of Openscales has been coupling. Put simply, historically loading different tools sometimes caused unusual side effects. This was particularly true for the draw tool. The newest code base corrects many of these problems. I’ve taken this code base and, with some modifications, have successfully built a base application where tools are loaded in a modular way and, most importantly are independent.
Figure 1 – Flex Openscales Map Demo
The ArcGIS Flex API is more complete than OpenScales. So more built in functionality up front. Plus there is a community building widgets which can make feature additions fast. I’m cautious saying this since one solution does not fit all. I find myself spending considerable time extending/editing these widgets. Building tools from scratch is also a time consuming exercise. Measure, buffer, coordinate, redline tools all take time.
So can this all be done in OpenScales and at what about cost? Yes, but …….
Building tools will likely take longer in OpenScales. Largely because it is likely more work will need to be done upfront. So you will be paying more for developer time. This obviously then needs to be weighed up against the cost of an ArcGIS license. OpenScales is a more challenging API to work with than ArcGIS. Put simple, it is easier to add tools using the ArcGIS API. So you will need an experienced Flex developer or team of developers, to build your OpenScales application. Geoserver is my preferred spatial server. You’ll need somebody well versed in this server or an alternate OGC spatial server.
WMS and WFS offer some interesting possibilities for styling maps and interactivity. They are fully supported in OpenScales, unsupported or rather supported in part by ArcGIS.
Figure 2 – Openscales WMS Styling
Querying in Openscales takes advantage of the OGC open standard, using WFS filtering for example.
Figure 3 – Openscales WFS Query
So yes, Openscales is a potential alternative to ArcGIS. More work may be needed to add complex tools or functionality. But there are many advantages. Overall cost, flexibility and control. As the community continues to build the code base, these advantages can only increase.