Panaji, Feb 16 (IANS): Google satellite imaging and global positioning systems (GPS) are flawed when it comes to monitoring illegal mining and encroachment of forest land by mining companies, the Goa government has told the Supreme Court.

"The reliance on Google imagery to allege encroachment is absolutely erroneous and technically unsound," Principal Secretary (Mines) Rajani Kant Varma said in his affidavit before the apex court Friday.

The Supreme Court is hearing a public interest litigation on rampant illegal mining in the state filed by an NGO and activist-lawyer Prashant Bhushan.

Both the Justice M.B. Shah Commission and a Supreme Court-appointed committee to probe illegal mining in Goa had used GPS technology and Google imagery to track rampant encroachment by mining companies beyond their lease areas.

The Goa government now claims that there was a technical discrepancy in the Google maps software "with respect to altitude correction" and that hand-held GPS surveys were "not accurate to precisely identify encroachment as these GPS have an inbuilt error".

However, Varma said that despite the "errors" in the findings of the two authorities, the Goa government had already issued show cause notices to 100 people for alleged encroachment.