An apparatus, comprising: a tracking system configured to track a location of a probe within an organ of a human body; a baseline coordinate system; a display; and a processor configured: to perform a first registration of the tracking system with the baseline coordinate system, to measure first locations of the probe within the organ following the first registration, to present, on the display, first indicators (110A-110C) on an image of the organ marking the first locations with a first visual effect, at positions on the image that are determined in accordance with the first registration, after measuring the first locations, to perform a second registration of the tracking system with the baseline coordinate system, to measure second locations of the probe within the organ following the second registration, and characterised in that the processor is further configured to present, on the image of the organ, second indicators (110D, 110E) marking the second locations with a second visual effect, which is visually distinct from the first visual effect, at positions on the image that are determined in accordance with the second registration. a tracking system configured to track a location of a probe within an organ of a human body; a baseline coordinate system; a display; and a processor configured: to perform a first registration of the tracking system with the baseline coordinate system, to measure first locations of the probe within the organ following the first registration, to present, on the display, first indicators (110A-110C) on an image of the organ marking the first locations with a first visual effect, at positions on the image that are determined in accordance with the first registration, after measuring the first locations, to perform a second registration of the tracking system with the baseline coordinate system, to measure second locations of the probe within the organ following the second registration, and characterised in that the processor is further configured to present, on the image of the organ, second indicators (110D, 110E) marking the second locations with a second visual effect, which is visually distinct from the first visual effect, at positions on the image that are determined in accordance with the second registration. to perform a first registration of the tracking system with the baseline coordinate system, to measure first locations of the probe within the organ following the first registration, to present, on the display, first indicators (110A-110C) on an image of the organ marking the first locations with a first visual effect, at positions on the image that are determined in accordance with the first registration, after measuring the first locations, to perform a second registration of the tracking system with the baseline coordinate system, to measure second locations of the probe within the organ following the second registration, and characterised in that the processor is further configured to present, on the image of the organ, second indicators (110D, 110E) marking the second locations with a second visual effect, which is visually distinct from the first visual effect, at positions on the image that are determined in accordance with the second registration.