A first look at ENVI 5

Excelisvis, the clumsily named successor to ITTVIS, successor to RSI ( I may have missed a few iterations here), has released a new version of ENVI, ENVI 5!

I’ve installed the new version and am ready to give my first impressions. So is it hubba, hubba or more Jabba the Hutt?

First, let’s look at the new interface: gone are the Image, Scroll and Zoom windows: in their place is a single GUI with in built zoom functions (Fig. 1).

Figure 1. The New ENVI 5 GUI is a complete break from the past.

Clearly ITTVIS/Excelisvis have been planning or at least contemplating this change for a while: hence ENVI Zoom. One of my colleagues has had ENVI phobia largely due to the old 3 window setup. So it will be interesting to see if the new look wins over new customers. That said, the GUI is hardly a slick polished product. The icons are a flat blue, the GUI background dull gray and the overall effect is of a SUN/UNIX application from the 1990s. It has ‘Python’ written all over it.

That said, we are offered some nice touches. Prominence is given  to image enhancements and vector annotations in the main toolbar. Stretches are found in a dropdown menu; contrast, brightness and transparency can all be easily adjusted making visualisation and image analysis that bit easier. It is still simple to link datasets geographically: just open two ‘Views’ in the eponymous menu and load your respective images, before choosing Geo Link Views (Fig. 2). Incidently, you are not limited to 2 views but up to 16 in a 4 x4 arrangement. This could be one of the best things since sliced bread!

Figure 2. Viewing mulitemporal datasets has become a lot more user friendly with the tools in the Views menu.

Other nice touches include the provision of georeferencing information (coordinates and projection) along the bottom of the GUI, admittedly a long overdue improvement, an ArcGIS style Layer Manager positioned on the left of the interface (though hopefully that’ll be where the adoption of ESRI practises stops), and new visualisation aids that allow you to switch between image layers in different ways (blend, swipe and flicker).

One change I am not totally sold on is the new arrangement of the processing algorithms. Gone are thematic drop down menus and in their place is a list of folders on the right hand side, arranged by theme (e.g. SPEAR, Image Sharpening, Statistics…).  Few of these seem new, so experienced users should be familiar with the content of these folders even if it takes a minute to find particular tools. One new feature is the LiDAR folder with contains a 3D LiDAR Viewer (Fig. 3).

I’ve played a little with the 3D LiDAR viewer and found it useful, though at time frustrating. Firstly, the viewer requires a mouse with a wheel to zoom and navigate: alternatives are not supported. My Roller Mouse and upright mouse both caused problems including an incredibly irritating flicker/refresh of the data. having eventually found an old mouse with wheel this issue was resolved and i could navigate around the LiDAR data in 3D, as promised. My LiDAR data, not untypically, contained a few erroneous features in the form of data spikes. The new 3D LiDAR viewer did not handle these well. The filter function had no effect and left me wondering if there was an ‘Apply’ button missing from the GUI. The visualisation lacked full spectrum colour because I couldn’t sucessfully perform a stretch to ignore the erroneous values. So, whilst I could see the potential, the experience was disappointing. On the positive side Mensuration in 3D is supported and the 3D navigation was responsive and fast (on a 64 bit machine with lots of RAM admittedly).

Figure 3. A 3D surface visualisation in the 3D LiDAR Viewer. Data can be viewed as Point Clouds, in Mesh form , or as Surfaces.

To summarise my first impressions: some of the new features are quite clearly just updates that bring ENVI in line with other professional packages (e.g. the georeferencing information below the image window). A cultural change is evident: the new single window GUI. We’ll see if this attracts new users or alienates those at home with the three window system: I think the new tools immediately accessible in the GUI are a winner. Finally, the flexibility inherent in the Views is a really nice touch and hopefully indicates a new approach in ENVI: making ENVI work for users, not least those with large datasets. So for now, ENVI 5 gets the thumbs up.

My next goal is to look at the integration with ArcGIS and explore the new functions in ENVI 5: watch this space.

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