The other form of target could look like one of the following:
This type of target type (that uses straight lines as opposed to using a circular dot) can be manually marked or in some cases be marked by the Template Target sub-pixel marker. See Template Target Marking for more detail. These cannot be marked by the Circular Target Sub-pixel marker.
When one of these targets appears large enough in the photographs being marked you can zoom in and very precisely mark the center of the target. When targets such as these are marked with care on four or more photographs with good angle separation, the resulting 3D point location will be very accurate. Depending on the size required, these targets can often be created on 8.5"x11" paper in a laser printer.