All about G99 Files

The G99 file type is primarily associated with HEC-RAS.

G99	File extension: G99
	File type:	Geometry File

What is a G99 file?

G99 files mostly belong to HEC-RAS by U.S. Army Corps of Engineers. Hydrologic Engineering Centers River Analysis System (HEC- RAS) is a one-dimensional steady flow hydraulic model designed to aid hydraulic engineers in channel flow analysis and floodplain determination. The results of the model can be applied in floodplain management and flood insurance studies. These files can have extensions from G01 through G99.

How do you open G99 files?

You need a suitable software like HEC-RAS to open a G99 file. You need a suitable software like HEC-RAS from U.S. Army Corps of Engineers to open a G99 file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your G99 file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a G99 file directly in the browser:. Just drag the file onto this browser window and drop it.

Online G99 Text Viewer

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.G99 File Won't Open? Here is What You Can Do

Because .G99 files come from specialized programs, they aren't universally openable.

Identify the Source: If received from a civil engineer or hydrologist, it is likely a HEC-RAS Geometry File.
Check the Header: Open the file in a text editor or hex viewer to inspect the first bytes.
- Plain text with river data implies a HEC-RAS file.
- "PK" indicates a zipped archive.
- Unreadable symbols suggest a binary format.
Use the Original Software: You usually need the original program, like HEC-RAS by the U.S. Army Corps of Engineers; if unsure, ask the sender.
Use this Webpage: Drag and drop your .G99 file here to detect its format, extract readable text, and preview it.

Technical Data for G99 File Extension

Identifier:

Hex: 47 65 6F 6D 20 54 69 74 6C 65 3D, ASCII: Geom.Title= (provided by TrID database)

Related files:

g02, g03, g01

a g99 Geometry File is a special file format by U.S. Army Corps of Engineers and should only be edited and saved with the appropriate software.

How to solve problems with G99 files

Associate the G99 file extension with the correct application.
Update your software that should actually open geometry files. Because only the current version supports the latest G99 file format. Search, therefore, e.g. on the U.S. Army Corps of Engineers manufacturer website after an available HEC-RAS update.
To make sure that your G99 file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
Click here to open your .G99 file online - secure, fast, and no downloads needed.