HEC-RAS File Formats¶

Reference for HEC-RAS file types and naming conventions.

Project Files¶

Extension	Description
`.prj`	Project file - master index of all project files
`.rasmap`	RASMapper configuration (terrain, land cover paths)

Plan Files¶

Extension	Description
`.p##`	Plan file (e.g., `.p01`, `.p02`)
`.p##.hdf`	Plan results HDF file
`.p##.tmp.hdf`	Temporary results during computation
`.computeMsgs.txt`	Computation messages log

Geometry Files¶

Extension	Description
`.g##`	Geometry file (e.g., `.g01`, `.g02`)
`.g##.hdf`	Preprocessed geometry HDF (hydraulic tables)
`.c##`	Geometry preprocessor cache files

Flow Files¶

Extension	Description
`.f##`	Steady flow file
`.u##`	Unsteady flow file
`.b##`	Boundary conditions (older format)

File Numbering¶

Files use two-digit numbering: 01 through 99.

Text Only

MyProject.prj          # Project file
MyProject.p01          # Plan 01
MyProject.p01.hdf      # Plan 01 results
MyProject.g01          # Geometry 01
MyProject.g01.hdf      # Geometry 01 preprocessed
MyProject.u01          # Unsteady flow 01

Plan File Structure¶

Plan files (.p##) are ASCII text with key-value pairs:

Text Only

Plan Title=My Simulation Plan
Short Identifier=Plan01
Geom File=g01
Flow File=u01
Computation Interval=5MIN
Output Interval=15MIN
Run HTab=1
Run UNet=1
Run SedTran=0

Geometry File Structure¶

Geometry files (.g##) use FORTRAN-style fixed-width formatting:

Text Only

River Reach=Big Creek,Upper
Type RM Length L Ch R = 1 ,1000   ,500    ,300    ,400
XS GIS Cut Line=2
     -100.0      500.0
      100.0      500.0
#Sta/Elev= 5
        0      105
       50      100
      100       98
      150      100
      200      105

Cross Section Format¶

8-character fixed-width fields
Station-elevation pairs
Maximum 450 points per cross section
Bank stations require interpolation

Unsteady Flow File Structure¶

Unsteady flow files (.u##) contain boundary condition definitions:

Text Only

Flow Title=100-Year Event
Program Version=6.50
Boundary Location=Big Creek,Upper,1000,         ,                ,                ,                ,
Interval=15MIN
Flow Hydrograph= 10
         0       100
       0.5       200
         1       500
       1.5      1000
         2      2000
         3      1500
         4      1000
         5       500
         6       300
         7       200

HDF File Structure¶

HEC-RAS 6.x+ stores results in HDF5 format:

Text Only

/
├── Plan Data/
│   ├── Plan Information/
│   └── Plan Parameters/
├── Geometry/
│   ├── Cross Sections/
│   ├── 2D Flow Areas/
│   └── Structures/
└── Results/
    ├── Unsteady/
    │   └── Output/
    │       ├── Output Blocks/
    │       │   └── Base Output/
    │       │       ├── Unsteady Time Series/
    │       │       └── Summary Output/
    │       └── Geometry Info/
    └── Summary/
        ├── Compute Messages (text)
        └── Volume Accounting/

Key HDF Paths¶

Path	Description
`/Results/Unsteady/Output/Output Blocks/Base Output/Unsteady Time Series/2D Flow Areas/`	2D mesh time series
`/Results/Unsteady/Output/Output Blocks/Base Output/Summary Output/2D Flow Areas/`	2D mesh summary
`/Geometry/2D Flow Areas/{area}/Cells Center Coordinate`	Cell center points
`/Results/Summary/Compute Messages (text)`	Computation messages

RASMapper Configuration¶

.rasmap files are XML format:

XML

<RASMapper>
  <Results>
    <Layer Name="depth" Type="RASResultsMap">
      <LegendFilename>depth_legend.xml</LegendFilename>
    </Layer>
  </Results>
  <Terrain>
    <Layer Name="Terrain">
      <Filename>.\Terrain\terrain.hdf</Filename>
    </Layer>
  </Terrain>
</RASMapper>