CirWarp – Circular Chart Digitizing / Integration



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Circular Gas Chart Digitizing & Integration Service

Latest Update

CirWarp circular chart digitizing service is now available as a Web App. Visit CirWarp.Online to check it out !



Circular gas charts have been in use for many decades in the natural gas production optimization and volume monitoring disciplines. There are multiple variants of gas charts with varying scale configuration depending on the manufacturer of the chart papers and recorders.

Previously, reading these gas charts would require either manual eye-balling on discreet points, or digitizing using a mechanical apparatus. These methods are exposed to many risks such as human error, mechanical calibration error, chart paper deformity / wear and others.

Geo-Zen introduces CirWarp, a circular chart digitizing service to quickly digitize and integrate circular gas charts of 12” diameter in size and below using an automated computer system. The output can be customized according to the customer’s objective according to a specified calculation method.

How It’s Done

Our integration process involves four main elements:

  1. Scanning
  2. Digitizing
  3. Analysis
  4. Output Delivery



Our company has researched an optimum way to digitize circular charts for integration purpose. This step involves complex calibration steps that varies between different combinations of scanners, scan configuration and chart papers. Streamlining this process within our control enables us to offer synergized value at cheaper cost to the customer.

However, if our customer prefer to do the scanning step on their own, they are still welcome to use our service but this comes with an additional image processing surcharge (in order to standardize differences in scanned charts prior to our automated integration process). To ensure the highest level of service quality and output, we also will have to reject non-optimal images if these are passed to us by our customers.


Using pre-defined calibration points specific to each gas chart type, we will run the scanned circular gas chart images through our software to extract chart values. We do this by initially warping the circular gas chart into a linear chart using our proprietary algorithm.


Figure 1- Original circular gas chart


Figure 2- Linearized gas chart produced by CirWarp


If the gas chart is of a new type that we have not worked on previously, we will consult and work together with the customer to confirm the curve-to-scale pairing and derive the correct calibration points. If this case, we will need some time to setup the calibration points and curve digitizing automation.


After the chart values have been extracted, an analysis or calculation on the numbers will be performed according to our customer’s specification. For simple statistical analysis methods such as mean, standard deviation, maximum and minimum, this is readily offered at no extra cost. Advanced analysis will require further consultation.


Output Delivery

All resulting artifacts from the above processes will be delivered back to the customers. These includes:

  1. Scanned gas chart images (if scanned by us)
  2. Linearized gas chart (for QC purpose)
  3. Chart values (in text, comma separated values or spreadsheet format)
  4. Analysis results (in text, comma separated values or spreadsheet format)


Quality Control / Assurance

Our customers can always be sure that each of the steps is easily verifiable by all parties. We are able to identify any problems at any stage of the integration process. These would be corrected if remediable, or communicated back to the customer if otherwise.

During a run, each of the provided circular gas chart will be processed into a linearized gas chart. If there are any errors introduced during the scanning step, the output produced will be skewed or distorted. Therefore, a quick glance at the linearized gas chart can tell anyone that the scan job and calibration points were done correctly.

The linearized gas chart is also easily readable and may be compared against the produced chart values for QC purpose. Then, by loading the produced values into a spreadsheet and plugging in the provided calculation method, the analysis results can be verified.


If our service offering interests you, please get in touch with us by e-mail at

Hassan S

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