The data rescued by the International Environmental Data Rescue Organization (IEDRO) enables the meteorological and scientific communities to provide more accurate severe weather forecasting and to understand climate change.
The IEDRO Strip Chart Digitizer program retrieves data from scanned strip chart images and converts them into an accurate computer-readable format. The program is five to ten times faster than a trained person performing hand tracing.
What is the data rescue process?
Planning the Rescue
IEDRO volunteers meet by phone, via email, or in person with the “owners” of the data to be rescued. All parties sign an agreement to allow the rescued and digitized data to be freely available through an open and unrestricted database and a tentative implementation schedule is set.
Setting up the Site
The IEDRO volunteer assists the country’s national meteorological service in readying the data rescue facility, then purchases and installs computer and camera equipment and trains the data rescue personnel.
Photographing & Scanning Data in Jeopardy
Once all the old weather observations are sorted by station location and date, each sheet of observations is oriented on a stand so that the entire page of weather data is visible to the camera. As soon as the image is in perfect focus, the photograph is taken and stored in the camera’s memory. When the camera’s memory is full, the images are downloaded into the computer and saved to portable storage media.
Digitization Innovations: IEDRO’s Strip Chart Digitizer Program
Developed and tested by Dr. Ed Root, the IEDRO Strip Chart Digitizer program retrieves data from scanned strip chart images and converts them into an accurate computer-readable format. The program is five to ten times faster than a trained person performing hand tracing.
The Problem
Hydrometeorological “strip charts” record the changes in parameter values over time. Observational data such as temperature, atmospheric pressure, relative humidity, precipitation, stream flow, wind direction and speed, etc. are recorded as a pen trace on a grid. These charts are mounted on cylinders which rotate at a constant speed, and a pen, attached to a mechanical device, records the changes in parameter values over time. Depending on the speed at which the cylinder turns, the charts may represent parameter changes over a 24-hour period or a 7-day week.
Prior to the construction of the IEDRO Strip Chart Digitization Program, the process of extracting information from these charts and digitizing the values over specific periods of time involved manually running a digitizing pen over the trace on the chart (which was mounted on a light table), then entering the data on a form. This manual process usually took 15 to 20 minutes of effort.
The Solution
Dr. Ed Root, one of IEDRO’s talented volunteers, has spent nearly 3 years developing a computer program that will take a scanned or digitally photographed image of one of these charts and digitize the entire chart at any time interval requested
. The digitized data can be provided in a comma delimited file or transcribed in a table. The time required for the program to digitize a chart…less than 5 seconds!
The Future
Stay tuned to IEDRO through our website, www.IEDRO.org, or our free monthly newsletter. Sign up at admin@iedro.org.
Where does the rescued data go?
IEDRO first obtains the photographic or scanned images of the original environmental data (i.e. alphanumeric weather observations, graphs, photographs etc.), which are a direct result of IEDRO-planned and executed data rescue projects in developing countries. These images are usually provided on CD-ROMs or DVDs.
IEDRO logs the images received and sends a complete copy of the rescued data to the nearest environmental World Data Center – NOAA’s National Climatic Data Center (NCDC) in Asheville, North Carolina. NCDC’s government contractors key the alphanumeric data and copy the photographs and store both as digital files in their huge database.
These data are then available to anyone in the world community for research, educational, and operational purposes at a nominal charge.
IEDRO-funded data rescue projects have one requirement – digitized data that has been rescued is to be provided to the world community, primarily through a world data center, either at no charge or for a nominal charge of reproduction.
