RTI File Format (RiverTools Information)

RiverTools Information (RTI) files are small, ASCII "header" files that contain georeferencing and other descriptive information for a DEM grid file that has the same prefix. RTI files must conform to the following rules, which are included at the bottom of every RTI file.

  • RiverTools Information filenames must end with ".rti".

  • The first line in the file should be: RiverTools Info File

  • Any line that starts with a semi-colon is ignored.

  • Colons are used to delimit labels from values.

  • Values must be listed in a "standard" order.

  • The number of rows and columns are required.

  • Pixel geometry codes are: 0=Fixed-Angle (Geographic), 1=Fixed-Length (usually UTM).

  • Pixel x-resolution and y-resolution are required.

  • Measurement units must be METERS or DEGREES.

  • Elevation data type is required. Allowed types are: BYTE, INTEGER, LONG, FLOAT, and DOUBLE.

  • Byte order is required and must be specified as either LSB or MSB.
    • (LSB = Least Significant Byte = little-endian)
    • (MSB = Most Significant Byte = big-endian)


  • For 'fixed-angle' pixels, bounding latitudes and longitudes are required to compute lengths and areas correctly.

  • Bounding box coordinates are always for the outer edges of pixels as opposed to pixel centers.

  • Latitudes south of equator and longitudes west of prime meridian must be specified as negative numbers.

  • RTI files are most easily edited with the File → View DEM Info dialog in RiverTools but are simple text files that can also be created and edited with any text editor.