Total Runoff Integrating Pathways (TRIP)

1-degree Version : May 22, 1997 / 0.5-degree Version : Feb. 2001

The data may be irregularly updated. Please visit this page to obtain the latest information. Thank you very much for your interest in this research. Any comments and suggestions are welcome. Please contact with Taikan Oki at

Institute of Industrial Science
University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 JAPAN
Phone: +81 3 5452 6382, FAX: +81 3 5452 6383


What is TRIP?

"TRIP" is an acronym of "Total Runoff Integrating Pathways."

These pathways can help to isolate the river basins, inter-basin translation of water through river channels, as well as collect and route runoff to the river mouth(s) for all the major rivers. TRIP enables us to validate the runoff part of land surface parameterizations (LSPs) in GCMs. In conjunction with the river discharge data, TRIP will permit estimation of changes in runoff in climate change investigation.

TRIP will also be used in the coupled Ocean-Atmosphere-River-flow models to assess the changes in the history of the water cycle on the Earth. We are introducing a carefully crafted river channel network (call it a tool) to investigate the runoff part of the global water cycle. The tool is currently being used in "evaluation activity" of different Land-surface Process Schemes currently being evaluated under the GEWEX /ISLSCP Global Soil Wetness Project (GSWP).

A paper describing the design of TRIP was published in Earth Interactions. The article is:

T. Oki and Y. C. Sud, 1998: Design of Total Runoff Integrating Pathways (TRIP) - A global river channel network. Earth Interactions, 2.
(online abstract is also available) Please refer the paper above if you think the TRIP is valuable for your research.


Data Access to the current version of TRIP

Current version of 1-dgree TRIP is "970522," and resolution of 1 degree by 1 degree longitude/latitude grids.

0.5x0.5 degree version is also available.

Versions of 2.5 x 2.5, and 4.0 x 5.0 resolution are planned.

These data may be used only for academic purposes with no guarantee. Please inform me if you find any errors in the data. I would appreciate if you will tell me about any publication of research results using the data.

Please do NOT redistribute without notice.

Each 1 degree by 1 degree grid point is allocated a number which indicates the outflow direction from the grid point. Grid point can have eight outflow directions; North (1), North East (2), East (3), South East (4), South (5), South West (6), West (7), and North West (8).

8 1 2
7 9 3
6 5 4

Missing value, indicating that grid point is water surface in the Land/Sea Mask of ISLSCP Initiative I Dataset, is 0.

"9" (and "12", only for 0.5x0.5 version) implies that no outlet from that grid point. It could be a river mouth (or an inland depression).

All Files Archive :
FILE 1 degree version
0.5 degree version
(compressed : 320KB)
tar.gz zip tar.gz zip *.asc
Download Download Download Download Download
Binary format (BIG endian) file, text format map file, Arc/Info *.asc file and ascii x-y-value file were archived and compressed by tar.gz and zip.
Binary format (BIG endian):
FILE 1 degree version
0.5 degree version
Download Download
1-degree version : 4 byte real of 360x180 data are written from (0.5 E, 89.5 N) to (359.5 E, -89.5 N).
0.5-degree version : 4 byte real of 720x360 data are written from (0.25 E, 89.75 N) to (359.75 E, -89.75 N).
The program below will read the binary data file of 1-degree TRIP.
      integer i, j
      integer infile
      real trip(360, 180)

      infile = 15

      open(infile, file='trip.bin', access='DIRECT'
     $     , recl=4*360, form='UNFORMATTED')
      do j = 1, 180
        read (infile, rec=j) (trip(i, j), i = 1, 360)
      end do
      close (infile)
The longitude and latitude for "trip(i,j)" can be calculated as
      rlon = real(i)-0.5
      rlat = 90.5 - real(j)
C Language
#define Y_SIZE 180 /* for 0.5-degree TRIP, set this to 360 */
#define X_SIZE 360 /*                                  720 */

#include <stdio.h>

  int iy;
  float fTRIP[Y_SIZE][X_SIZE];
  FILE *fp;

  fp = fopen("trip.bin", "rb");

  for(iy = 0; iy < Y_SIZE ; iy++){
    fread((void *)(fTRIP[iy]), 4/*byte*/, X_SIZE, fp);    
The longitude and latitude for "fTRIP[iy][ix]" can be calculated as
      fLon = 1.0 * ix + 0.5;
      fLat = 89.5 - iy;

Text format :
FILE 1 degree version
0.5 degree version
Show/Download Show/Download
1-dgreee version : TRIP information is stored in a text file of 360 column by 180 lines from (0.5 E, 89.5 N) to (359.5 E, -89.5 N).
0.5-degree version : TRIP information is stored in a text file of 720 column by 360 lines from (0.25 E, 89.75 N) to (359.75 E, -89.75 N).
"+" is used for "9" and "12," and "." is used for "0."
ASCII data format:
FILE 1 degree version
0.5 degree version
Download Download
TRIP information is indicated by a line for a grid point. Each line has longitude, latitude, and TRIP number. Grid points only over land area are included.
Arc/Info ASCII data format (*.asc):
FILE 0.5 degree version

netCDF data format (*.nc): user contribution by Ufuk Turuncoglu
FILE 0.5 degree version
This version also contains Major River Basins Templates.


Support Data for Routing Simulation using TRIP

River Sequence:
FILE 1 degree version
0.5 degree version
Download Download


Figures of the current version of TRIP

Region 1 degree grid version 0.5 degree grid version
GIF FilePostScript File GIF FilePostScript File
(Size) (20-90 KB) (150-400 KB) (90-400 KB) (190-500 KB)
North America [NA] [NA] [NA] [NA]
South America [SA] [SA]
Africa [Af] [Af]
Europe [Eu] [Eu] [Eu] [Eu]
Asia [Asia] [Asia] [Asia] [Asia]
Oceania [Oc] [Oc] [Oc] [Oc]
Far East/West [FE] [FE] [FE] [FE]
All Files Archive tar.gz
(about 350KB)
(about 250KB)


Templates of major river basins on TRIP

Approximately 200 major river basins are delineated on TRIP. Data in the index file indicates the correspondences between river basin numbers and river names, and also the longitude and the latitude of the river mouth on TRIP are presented. The river basin number may change in the future version of TRIP and one must use the corresponding version of index file.

River basin numbers are in:
  1 deg 0.5 deg
Index File Download Download
Data Download
(Binary Format) (Sorry, now broken)
(ASCII map format)

[RIV] Global map of identified major river basins in 1-deg grid are available.

For detail of 0.5-deg grid data, please visit our Global Water Resource Archive. For example, you can obtain basin-code file (shown above) from basemap archive in that on-line resource.


Drainage area size on TRIP

In order to convert the discharge Q (m3/s) at the point, to the mean runoff r (mm/day) in the corresponding drainage area, the drainage area size A (km2) is required for the data conversion. The equation should be:

r = Q x 3600 x 24 / (A x 103)

River basin area (in 104km2) data are :

binary format (BIG ENDIAN; 250 KB): The format is same as trip.bin.
ascii data (600 KB) The format is same as trip.dat.
Note that the area for each grid cell in the files above was calculated assuming the Earth to be a spheroid in the meridional plane, not a perfect sphere. Please see details in the paper


Vector data of River Basin Boundaries


Information on river basin boundaries are extracted from the current version of TRIP in vector format. You may obtain the whole files (tar + gzip) or indivisual files.


Related publications to TRIP

There were accesses to this page in , .

(Last updated at Monday, 23-Jul-2018 22:19:00 JST, by Taikan OKI and AGATA, Yaushi)