Solutions for Sending Large Digital Files (Spatial Tech Column)31 Oct, 2007 By: James L. Sipes
GIS technologies are becoming key to managing services and resources.
In this day and age, patience is no longer considered a virtue, at least not when it comes to sharing digital information. When we hit send on an e-mail message, we expect it to be zapped across the country in the blink of an eye. E-mail works great for simple messages and text documents, but it's not a viable option for the large files typically associated with CAD, GIS, and imagery applications. These types of applications use high-resolution aerial imagery, detailed terrain models, and robust databases, and the increased detail and resolution produce larger file sizes than ever before.
How, then, do we share large CAD and GIS files in a way that is fast, simple, secure, and affordable? One option is to burn a CD or load files on a portable drive and then send the files via traditional mail or overnight delivery. But no self-respecting consultant or professional would make a client or colleague wait three or four days to receive information using snail mail, and FedEx gets to be pretty expensive.
An E-Mail Approach
It's difficult to transfer large files using e-mail. All e-mail accounts set a cap for the largest file you can send or receive as an attachment. For most, that cap is typically 10 or 20 MB. Most e-mail messages also lack encryption because both parties would have to use the same encryption system.
One problem with trying to send large files via e-mail is that the person on the other end may be using an e-mail server that can't handle larger files. For example, at EDAW, my colleagues and I routinely send and receive e-mails with attached files as large as 10 MB. We have a client, though, that has a maximum file size of 3 MB, and it's easy to lose track of this detail when sending files. If we send a message with an attached file larger than 3 MB, the e-mail bounces.
Traditionally, one technique for sending large files involves using a file transfer protocol (FTP) server. FTPs use the Internet's TCP/IP protocol to transfer files between computers. An FTP site is an efficient, affordable, and secure way to share digital data.
One problem with FTP sites is that they are not an effective way to transfer large files quickly. FTP sites are great if you can send files during the night and the person on the other end has time to download them. FTPs also require special software client and server administration, and they don't automatically notify receivers when a file is sent or provide status tracking.
File Transfer Approaches
Several applications seek to simplify the transfer of large files. The basic idea behind most of these programs is the same. You upload a file onto a service, e-mail the person you are sending the file to with a link to the file, and the recipient then downloads the file. Most services allow senders to drag and drop files into a browser window then simply type in an e-mail address as a destination. With these types of applications, e-mail is used only to deliver the secure link, so the limitations of the e-mail provider are not an issue. The process is much faster and more efficient than using an FTP site.
Most programs have a file-tracking and notification service, so senders can keep track of the status of files. Most also automatically resume uploads if Internet access is interrupted.
Some file-sharing programs provide a basic version of their software for free. As a general rule, free accounts are intended for use by individuals; they typically do not provide the capabilities needed for businesses. A word of warning, though, is that some of these programs bombard you with spam upon access.
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Many file-transfer programs use peer-to-peer sharing, in which the files on one computer are retrieved by another. Other programs use a hosted transfer model that loads files on a separate server. Peer-to-peer sharing is more flexible than the hosted transfer model, but the latter is a simple, effective approach for both senders and receivers.
File Transfer Applications
Avvenu, Civil Netizen, Driveway, DropSend, MailBigFile, Pando, Sendago, SendThisFile, and YouSendIt are just a few of the programs available for transferring large files. YouSendIt is a peer-to-peer file-sharing service with more than four million registered users. You upload a file on the YouSendIt server and the person on the other end downloads the file at their leisure. Avvenu uses a similar approach. Access to your PC is managed by Avvenu, and only authorized individuals can access your files.
With SendThisFile, you create a FileBox that allows you to receive large files from anyone through your account.
Civil Netizen can handle files and folders as large as 4 GB in total size, and all file-transfer traffic is secured between senders and recipients using 128-bit AES encryption. Pando is a peer-to-peer technology; it comes in a free version as well three premium services that transfer larger files at faster speeds. For the free version, Pando makes its money on pop-up ads that recipients see when downloading the files.
DropSend comes in five versions, ranging from a free version to a business version that costs $99. The latter version provides 250 GB of online storage and is available for as many as 100 users. In addition to being a standalone application, YouSendIt also provides plug-ins for popular graphics and e-mail applications, including Adobe Photoshop and CorelDRAW, so you can save and send a file directly from within those programs.
LeapFILE is a hosted service that streamlines the file-transfer process and provides a file-courier service for business applications. It costs from $10 to $250 per month, with the most expensive setup allowing 25 different user accounts, as well as transfer of as much as 20 GB of data and a maximum file size of 2 GB. You pay more with a service like LeapFILE because of the assurance that files are secure. Companies use programs such as LeapFILE to set up custom Web-based file-exchange sites for employees and clients.
Xdrive and Box.net take a different approach to sharing data. Both are online file-storage services that allow you to set up a personal hard drive that's accessible via the Internet.
Another option is for companies to build their own internal collaboration portals based around programs such as Microsoft's SharePoint Server that allow large files to be hosted. EDAW uses an internal system called SPEEDaw for access by employees, clients, and other companies and individuals working with EDAW to transfer business-related information.
Whatever e-mail service or method you choose, the options provide great options for sharing files.
James L. Sipes is a senior associate with EDAW in Atlanta, Georgia, and the founding principal of Sand County Studios in Seattle, Washington. Reach him at firstname.lastname@example.org.