Quantum GIS, first impression

If gvSIG friends fulfilled their promise, next Monday July 27th we will have the 1.9 stable version. So far the test has been great, according to the perceived volume of distribution lists. While waiting on Monday, by which time I hope to have the satisfaction of congratulating the performance of speech, at the cost of surely sleeplessness developers, let’s take a look at QGIS at the fly.

QGIS was developed in C + + using Qt toolkit, runs on Windows, Mac and Linux. The project was born in May 2002, with support for 26 languages and its license is GPL.

We will test the input version 1.02 that has left me quite pleased to be free to use tool that can be downloaded from this link and this is the official website of Qgis.

Appearance

The iconography and interface design is the most redeemable, does not affect usability, but indeed it affects in corporate taste (sell) at the time of offering. This aspect was previously criticized on gvSIG, because at some point in appearance and creativity disparity made that a manager told me “looks like a veteran program, some icons appear to have been made with 8-bit Paintbrush.”

But in this shallowness QGIS goes very well, even with a single click it can be choose between 3 different iconography themes very well conceptualized, just passing the mouse on the item shows how the interface would be seen.

Interesting features

QGIS requires Grass to many features that this tool has well established; it’s very good to avoid duplicating efforts. When you start QGIS and not find it installed, raise an alert in this case I’m doing a review without including Grass. When you want to load a Grass data set, as it was not installed the application got closed, so I do not recommend using it without installing both tools.

Shortcuts, A lot of commands have a letter assigned, so that you can load the function with the press of this letter. This is very handy; I remember that in AutoCAD this was one of the best tricks when almost everything was done via keyboard.

The overview in the left panel is a map showing the deployment area, with two-way synchronization. Very useful, you can choose which layers you want to see in the overview, and can be released as a floating window to different sizes.

The side frame, just great, you can drag the plugins as labels to the foreground, it can be made as floating, and with a simple right button it can be turn on or off. Also wide management is a simple drag not only in the left panel but at the bottom.

The bottom panel to display the attribute table, appears in the area, but can also be floating. It’s very functional, with zoom options to the selected rows and change of column’s width with a simple mouse drag. Also in the bottom frame have the search and selection functions, much like what Manifold GIS has, apart from simple status bar.

The formation of this interface design makes it more profitable, the floating frame is the best from the design; it reminds me of Microstation, as in the case, the window attributes can be deployed without affecting other operations.

Data analysis, has the basics of geoprocessing and research that anyone could require, at first glance there are some interesting features that I prefer to see on another occasion, because Ftools plugins include terrain modeling, hydrological and others.

Extra plugins, like any GPL application, its gain is in the plugins that are slowly created by the community (although with the advantage of not being in Java); by default brings the basic and they seem few but they are not as simple as they seem: WFS layers can be loaded, export to MapServer, capture a coordinate, add support to the view as north, scale and copyright, comma delimited text, has a dxf to shp converter, a plug-in for georeferencing images, gps console, python console, grid coordinates, etc. But the best is the option to load Grass plugins that are a separate issue. Similar to what happens with gvSIG and Sextant although the maturity of Grass is respectable, as it is one of the oldest GIS tools.

The OGR converter is interesting because it can convert layers between different formats, such as shp, dgn, gml, csv, kml, gpx, mapinfo, as well as spatial database via ODBC, MySQL, PostgreSQL, among others.

Basic functions, like other tools, it can be created spatial bookmarks, groups of layers, the layers have control of minimum and maximum zoom, easily to add coordinates and projection systems; in shp layers case, if they have prj, Qgis rescues this information. A lot of processes include a progress bar, which seems very good.

It is very interesting how are set objects attributes because in the same panel there are tabs for general properties, simbology, metadata, labels, actions and tabular attributes, all can be saved as a .qml style and loaded to apply to other layers . Also this is a floating table and can adjust its width and height as desired. Even this panel and others can be opened as a separate application.

Also striking are features that seem simple but are very useful, such as the continuous distance measurement, which is reflected in a tabular panel, which includes the distance of each segment.

Access and data editing

You can load vector data shp, gml, MapInfo and ddf, but you can convert data from other formats via OGR converter. Additionally vector layers can be converted via WFS and PostGIS. Salvageable allows you to specify the character encoding when loading the layer.

In regard to raster layers, supports a lot apart from WMS. Additionally it includes reading standards as OGC WFS, WCS, CAT, SFS, and GML.

To create new vector layers it can be made through OGR shape files or Grass. Projects are saved as XML with extension qgs, which is stored the layers formation with gvSIG style.

Regarding the data editing in the project properties are stored specifications as a coordinates system, units, decimal precision, empowerment of topological Edition permission or limiting overlap of polygons in a same layer and conditions to snap (type and tolerance) for each layer available in the project. The latter is interesting, although it disappointed me that it only has option to segment and vertex. Again, Grass should be a justification for this.

I tried to edit a layer inserting a vertex, but it seemed to me quite slow, apart it was necessary to add snapping options (sorry for my stupidity, is the first time I play this toy). I’ll see it after loading the Grass editing tools. Neither seems to have a track if several are editing a layer simultaneously, so that earns who save first. ugh!

Data Output

By the end of quick exit, there is no option to save the view as an image, and a plugin for quick print, but unlike gvSIG, has no layouts control as ArcView style, instead of this has a print composer that seems to me a little crazy (*), but allows you to load data frame, labels, boxes and symbols, and it can be created several compositions for a project, I didn’t found how to save as templates, the manual says it is possible. I guess in the Grass plugins there are better things for these purposes.

Comparison with gvSIG

Sure we will, after next Monday.