GPR Surveys in Urban Environment for Old Town Hall Remains Location in Lidzbark, Poland

This paper presents the results of a GPR archaeological survey, carried out in urban environment, with the aim to confirm the existence and state of the remains of the medieval town hall in Lidzbark, Poland, destroyed during the big city fire in 1865. Today, an idea emerged to reveal its remains and expose it as a monument. As a guidance for subsequent excavation, and to to evaluate the suitability of the GPR method for all of the planned area, a GPR survey was carried out within a limited area, in the form of regular grid of 0.5 by 0.5 m size, with 250 MHz antenna. Generally, the GPR image of the underground structures turned out to be very close to the reality. Several types of events were observed and analysed, some of them being easy to mistake with real wall remains, and some of them imaging the buildings remains very truly. Especially, the time slices and 3D rendering techniques proved to be very helpful during the analysis. The survey results can be regarded as very promising for the rest of the total area planned for excavations.