MADRID  A judge in Spain opened an investigation into whether Google unlawfully collected data from unsecured wireless networks while gathering photographs for Google’s photo-mapping service Street View.

The judge, Raquel Fernandino, has ordered a representative from Google to appear before her in early October over a lawsuit filed by a Spanish association of Internet users. The summons was issued last month, but made public only this week.

Street View has also caused regulatory and legal problems for Google in other European countries with strict privacy laws, including Germany and Switzerland, where opponents of the Street View photo archive have been particularly outspoken. In May, a judge in Hamburg opened a criminal investigation of Google over its collection of data from unsecured Wi-Fi networks in Germany.

Google has described the collection of the data as accidental and has apologized for what it called a programming error.