SOME EXPERIENCE IN BLUEPRINT COLLAGE

The blueprint collage method is an important method for transferring the content of one map to another in map compilation. Its advantage is that it is simple to operate and easy to use, and its disadvantage is that it is easy to produce fissures and folds in collage and thus influence the precesion of the map to a certain extent. In order to raise the precision of collage, not less than 16 control points are required for each sheet of the large-scale topographic map, and besides, what is important is that it is necessary to use the intersec- tion points of square kilometer lines （or longitudes, and latitudes） for collage control.