Draft operational guidelines of digital india land records modernization programme (dilrmp) introduction

9. QUALITY ASSURANCE

9.1 A comprehensive quality control program for ensuring the quality of data has to be followed based on the criteria provided and permissible accuracy. The measure of accuracy derived based on the allowable limits would fall under one of the following heads, viz., physical accuracy and logical accuracy.

9.2 Physical accuracy

In any data conversion, some amount of variations would creep into the data sets depending on the type of digitization procedures followed and the subsequent projection and transformation methods followed. Following tests would be made to ensure that all the features in a dataset are within the permissible limits:
Point features

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  Location of a feature with reference to a standard layer would be the same or within the prescribed limits.
  
• 
  A feature carries the same information after migration.
  

Line features

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  Variation in length of a line segment selected based on an attribute or combination of attributes.
  

Polygon features

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  Variation in the number of lines that makes the polygon, their length (perimeter) and subsequently amounting to area.
  

9.3 Logical accuracy

This accuracy corresponds to completeness and correctness of data when a data set is analyzed. Following tests would be performed to ensure the logical accuracy of the data sets:
An attribute query run on the datasets should give a consistent result in terms of

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  Number of features selected;
  
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  The content of the features selected.
  

Any data set resulting out of analysis of two or more datasets should be logical.
Any spatial query run on the datasets should give the same result in terms of

• 
  Number of features selected;
  
• 
  The content of the features selected.