Open CAD Tools, gvSIG editing tools

It was launched a very interesting features series that come from CartoLab and University of La Coruña as contribution. gvSIG EIEL implies different extensions really very useful for user’s management from gvSIG interface, custom forms and automatic validation.


But what most caught my attention is Open CAD Tools, which in its 0.2 version seems to take many community orders to concentrate and improve construction routines and data editing.

If something gvSIG has, GIS users like me enjoy, are creation tools in similar style we usually do with CAD, it has virtually everything we questioned from GIS specialized programs. When this extension is installed, it’s replaced extCAD that comes by default. User manual explains how to install only the extension, because it also comes as an executable but with an older gvSIG version.

They are grouped the following 11 commands into insert option: Point, Multipoint, Arc, Polyline, Multipolyline, multitasking, multipolygon, Regular Polygon, Rectangle, clip_image003Circle, Ellipse and Autopolygon.

While in Modify option there are the following 16 commands: Copy, Mirror, Rotate, Scale, Explode, Move, Edit vertex Add vertex, Remove vertex, Join, Rescan line, Cut line, Cut polygon, Rescan polygon, Internal polygon and Stretch .

There are in total 27 of which I remembered have been counted 21 before when I did AutoCAD commands comparison against gvSIG’s 1.9.

clip_image004What the most valuable of Open CAD Tools 0.2 is

To begin with, I think it is valuable right mouse button functionality, because once a command is initiated can function as “undo”. It seems to me very practical, because when geometry is being drawn, for example a polyline or polygon, it is common to mistake when placing a point; so ‘undo’ must be used rather than cancel carried out work, or continue for editing later…

So applying right mouse button, last point placed is deleted

There are also some keys to help with work, such as “tab key”, which allows navigating to a following element. A case is given, for example, when editing a complex geometry, such as a polygon which has many holes or multiple polylines.

clip_image005So pressing tab key leads us to the following geometry

Then there is space bar to finish job and letter C to cancel it. While some question so archaic keyboard use at this point, as shortcuts at middle of a command, it remains practical.

The routines for line and polygon rescan solve this great limiting factor when making already created geometry maintenance. While much of this comes with gvSIG, expansion that has been made to routines is very good; for example, when cutting a line or a polygon, appears a message asking if you want to preserve the remaining segment.

So, replace default tools by Open CAD Tools is a viable option. The only tool that is not placed there is the Line command, as it is created with Polyline command, being understand it only has one segment.

Other improvements are in snaps property settings in order not to affect machine’s speed. For this you can change the amount of geometry to be analyzed, layers and whether monitoring is done only to vertexes or edges.

Then, there is automatically an option to turn NavTable at geometry’s end. With this it could be completed alphanumeric data in same line production process. Although the greatest enhancement of this is that geometry completion is now an event, so that programmers can do other associated tasks such as:

  • Topologies’ review in a spatial base,
  • Trigger’s lifting announcing change to the database even though vector layers are not in a spatial base,
  • Or simply advising a database that there is already a specific geometry and must begin reporting integrity about tabular data. This can be the case when the card has been digitized but mapping goes slower.

It won’t be strange to see this extension in next gvSIG version, as we saw with NavTable. We think it’s a good example, which together with Fonsagua represent work results Foundation has matured in shaping industrial fabric that is one of the strong pillars for Open Source platforms sustainability.

To follow up this issue I suggest the following links:

And then watch this video for EIEL use in mapping roads.

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