Hello All, I have been on this for a long time and have done a lot of research / reading on this topic, HDF5. To use it for development of in-house software for design calculation of various alignments. A lot many time the basic alignment information is picked from a map / satellite imageries. Kilometre, ground level, geographic feature on the proposed route, etc. , in a csv file. Any where between 7-9 files are generated for each alignment. 1. How to read / write data into the HDF5 file ? What after creating root ? 2. In a regular situation, I have 2 input file with 3 column csv data, and 2 output files. How to do that within the same root ? Will be working in Python and c / c++. This is just the basic. If I can do this much, I can do the rest, hopefully :) Thanks to All Nitin PS :- Will post in scipy-user list too.