System for machining a workpiece - comprising a hand-held power tool having a drive motor, a tool holder, which can be driven by the drive motor, for a working tool for machining the workpiece, and a guide element with a guide surface for guiding the hand-held power tool on the workpiece, - having a marker detection device for detecting coordinate data (KD1, KD2) of at least one workpiece marker (M1, M2) of the workpiece, wherein the hand-held power tool has guide means for guiding the working tool along the workpiece according to the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2), wherein that the marker detection device has an optical and/or mechanical reference which can be positioned on and/or directly next to the at least one workpiece marker (M1, M2), in that the marker detection device is designed for determining the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2) relative to an at least two-dimensional coordinates system (KR2, KR3) which is independent from the workpiece marker (M1, M2), and wherein the guide means of the hand-held power tool are designed to guide the working tool relative to the at least two-dimensional coordinates system (KR2, KR3) in a working area which is geometrically defined by working area data determined based on the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2) characterised in that, in order to provide the at least two-dimensional coordinates system (KR2, KR3), it has at least one coordinates sensor (80, 81; 180) which can be placed in a working space in which the workpiece is arranged, and the guide means and/or the marker detection device are designed to determine the position of the at least one coordinates sensor (80, 81; 180) and/or to determine reference information (RX, RY) transmitted by the at least one coordinates sensor (80, 81). - comprising a hand-held power tool having a drive motor, a tool holder, which can be driven by the drive motor, for a working tool for machining the workpiece, and a guide element with a guide surface for guiding the hand-held power tool on the workpiece, - having a marker detection device for detecting coordinate data (KD1, KD2) of at least one workpiece marker (M1, M2) of the workpiece, wherein the hand-held power tool has guide means for guiding the working tool along the workpiece according to the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2), wherein that the marker detection device has an optical and/or mechanical reference which can be positioned on and/or directly next to the at least one workpiece marker (M1, M2), in that the marker detection device is designed for determining the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2) relative to an at least two-dimensional coordinates system (KR2, KR3) which is independent from the workpiece marker (M1, M2), and wherein the guide means of the hand-held power tool are designed to guide the working tool relative to the at least two-dimensional coordinates system (KR2, KR3) in a working area which is geometrically defined by working area data determined based on the coordinate data (KD1, KD2) of the at least one workpiece marker (M1, M2) characterised in that, in order to provide the at least two-dimensional coordinates system (KR2, KR3), it has at least one coordinates sensor (80, 81; 180) which can be placed in a working space in which the workpiece is arranged, and the guide means and/or the marker detection device are designed to determine the position of the at least one coordinates sensor (80, 81; 180) and/or to determine reference information (RX, RY) transmitted by the at least one coordinates sensor (80, 81).