The Tao of CAD and GIS

5 May, 2009 By: Kenneth Wong

Now in beta testing, a new on-demand viewing and markup tool lets users collaborate on a file simultaneously.

Tao, a Chinese word loaded with philosophical implications -- as in Tao Te Ching or Taoism -- is probably the last thing that comes to mind when you're sorting out DWG files, contour lines, and raster files. But that may soon change, thanks to a team of Israeli software developers.

Recently, a startup called VisualTao quietly came online. The company was cofounded in early 2007 by Jonathan Seroussi and Tal Weiss, developers who once worked for Israel Aerospace Industries. Philosophically, the company is aligned with the software-as-a-service (SaaS) movement, championed by others such as Arena Solutions and

VisualTao's tagline is "CAD on Demand," but its market may be much broader. Its web-based viewing and markup tool is designed to let you "co-edit and collaborate on CAD and GIS data over the web," making it ideal for crossover disciplines such as civil engineering and utilities. Consistent with the SaaS model, VisualTao's product doesn't require installation. You subscribe to it and use a standard web browser to access its features.

On its home page, the company proclaims, "VisualTao is actively working on future developments and partnerships to enhance its technological platform and end-user solutions." All indications point to a company still in the embryonic stage, still refining its product. The signup page indicates that the company is recruiting beta testers. This may be a rare opportunity to help shape a promising product.

VisualTao, a new firm currently recruiting beta testers, plans to offer browser-based CAD and GIS viewing and markup features by subscription.


Unlike many other collaboration products, VisualTao accommodates co-navigation and co-editing sessions. Note the two different active cursors in this view.

How It Works

Most likely, you'll begin by uploading a series of drawings to your workspace, configured to be accessible to your colleagues and collaborators. The product seems to have been developed specifically for review cycles. In addition to the navigation tools (zoom, pan, rotate, and so on), you can also use the editing toolbar, which lets you attach xref files, annotate, dimension, draw lines and primitive shapes, and delete items.

CEO Weiss pointed out, “Users are not limited to adding overlays and markups to drawings, but that they can edit drawing geometry, text, and block objects. Today, this is something that can't be done over the web or without a preinstalled desktop CAD editor. They can directly apply those changes made during a review or co-editing session to the file on [VisualTao’s] server or download a version containing the changes to their desktop.”

The real-time collaboration option lets you launch a co-navigation session, wherein two parties can interact with the file simultaneously. Weiss verifies that the software currently supports up to four co-editors at a time. This feature distinguishes VisualTao from other online collaboration tools that let you work with others by passing the control baton, a method by which only one participant can interact with the drawing at a time. (In other words, the person with the baton works while others watch.) With VisualTao, your collaborators do not need to be subscribers in order to work with you. The company's FAQ explains, "You can invite any number of unregistered users via e-mail to collaborate with you."

The integrated chat window lets you send and receive text messages or voice over IP, much in the same way you would in Google Talk or Yahoo! Messenger. At the end of the collaboration session, you can archive a transcript of the discussion, complete with a record of the edits to the drawing and the comments added.

The permission setting lets you define the rights of your collaborator. Whether the other party can edit the drawing, just view it, or download it is determined by the checkmarks you put in this window.

Along with these tools, VisualTao gives you a view of the big picture via the dashboard, which lists all your discussions and the associated messages and participants. The discussion view shows you the relevant messages and collaborators in a consolidated window (no more digging into Outlook Inbox or searching through the messages using a keyword).

To circumvent the need to upload a new drawing to the workspace whenever you work offline, VisualTao lets you synchronize your desktop files and online files through its Sync Utility, a downloadable thin-client application.

VisualTao supports DWG and DXF with embedded drawings or xrefs, fonts, and style sheets. The application can link to popular geospatial databases, including ESRI ArcSDE, Microsoft-SQL, and Oracle Geospatial. Its raster-image support encompasses JPG, PNG, BMP, and GIF. Because it's a web-based viewer, you can plot and print directly from the browser.

Back-End Architecture

For data storage, VisualTao is using Amazon Elastic Compute Cloud (EC2), part of Amazon's web services. In its service-level agreement, Amazon promises "99.95% availability for each Amazon EC2 region." Therefore, barring any technical mishaps on VisualTao's own setup, VisualTao subscribers can expect the same reliability.

The company uses Open Design Alliance's DirectDWG Toolkit to read and write DWG files. For relational-database connectivity, the company uses Open-Source Geospatial Foundation's (OSGeo) Feature Data Object API.

Explaining its technology, the company writes, "Drawings and maps are streamed to end users in true vector form, enabling accurate queries and measurements and precise updates of object and metadata. Optimized data compression and streaming methods ensure a high level of performance over standard Internet networks."

At the moment, VisualTao 1.0 is a 2D viewing and markup tool, but the company is working on adding 3D support by version 2, it reports. The current version limits file size to 50 MB per drawing, but the company hopes to remove this restriction in future versions.

AfterCAD Online, another SaaS viewing and markup solutions provider, recently added 3D support to its application, powered by open-source game engine OGRE. Google's recent release of O3D API as open-source code gives developers like VisualTao another affordable option for adding 3D support.

Alternative Viewers

GIS software maker ESRI offers ArcGIS Explorer, a free, lightweight desktop application for viewing geospatial files stored in ESRI's ArcGIS Server. The company also offers ArcExplorer, a free, standalone application to display and query geospatial data.

CAD-to-GIS exchange can also be accomplished via ArcGIS for AutoCAD, another free utility from ESRI. The plug-in creates a toolbar inside AutoCAD, allowing you to display maps stored in ArcGIS right from the AutoCAD editing environment. But the application's support is limited to AutoCAD 2007 and 2008 only.


Unlike VisualTao's SaaS product, these three ESRI utilities require downloading and installing a lightweight program on your local machine. They give you the ability to open and interact with GIS files without owning or installing GIS software, or for asynchronous sharing of CAD and GIS files, but they're less than ideal for real-time collaboration.

To uphold the SaaS tradition, VisualTao can be expected to offer its solution for an affordable monthly or annual subscription fee. But the company has yet to publish its prices. Perhaps, as beta testers, you might be able to weigh in on how much you're willing to pay. The product is scheduled to launch this summer, according to Weiss.