The preparatory work involved in building a geological GIS involves the integration and georegistration of topographic base maps, existent geological maps, aerial photographs, radarsat and satellite images, and various kinds of geophysical data into a single system of digital layers. For example integration of  data sources, 1:20000 basemaps, geological map 2491, and airphotos for the Coniston Region of  Sudbury might involve creation of the following layers as part of an autocad .dwg file:
 
     Alines 2491  Geological boundaries
     Alinestemp  temporary lines
     Beds2491  trends of bedding taken from map 2491, and trend lines based on
    all bedding orientations
     Faults2491  faults taken from map 2491
     Geolbruce2491  polygons for the Bruce Formation
     Geolbruce2491fil  colour filled polygons for the Bruce Formation
     Geolgabbro2491  polygons for the Nipissing diabase
     Geolgabbro2491fil colour filled polygons for the Nipissing Gabbro bodies
     Geolpecors2491  polygons for the Pecors Fm
     Geolpecors2491fil  colour filled polygons for the Pecors Fm.
     Geolsuddiab2491  polygons for the Sudbury diabase
     Geolsuddiab2491fil colour filled polygons for the Sudbury diabase bodies
     GeolMiss249  polygons for the Mississagi Fm
     GeolMiss249fil  colour filled polygons for the Mississagi Fm.
     Glakes2491  lakes
     Glocation118  location of points on airphoto 118 that are recognisable on the basemap
     Glocation120  location of points on airphoto 120 that are recognisable on the basemap
     ETC
     Glocation2491  location of points on map 2491 that are recognisable on the basemap
     Glocationnames  names/coordinates of location points.
     Grail2491  railroads
     Groads2491  roads
     Gwater2491  rivers and streams
       boundaries of aerial photographs
     Photo118  airphoto 118
     Photo120  airphoto 120
     ETC
     Studentsstati  stati localities on student maps
     Studentsstruct  oriented bedding symbols, data from student maps
 
     In order to carry out georegistration of the various data sources, it is necessary to first make a list of the coordinates of locations that are present on the basemap and which can also be recognised on corresponding airphotos and the existent geological maps that are to be digitized, at the same time  marking the location points on the maps and airphotos  (use white ink on the airphotos).
     If using an ODBM digital basemap, and if the datum for the map is NAD27, create a new empty file in Autocad Map, assign NAD 83 as the UTM projection for the relevant zone, attach and query 'all' to bring in the basemap, use  move 'all' to add 4000000 to the northing values of all plotted objects (select 'move' 'all' 0, 4000000, enter), and save as a new file, e.g. 51-v1283.dwg.
     Plot the locations (Point) on each map to the corresponding location layer (e.g. Glocation118) in Autocad Map, and add the names (Text) of the points to the Glocationnames layer. If the location coordinates were determined from a 1:50000 basemap, the accuracy will likely not be better than 25 meters, where, at this scale, 25 meters = 0.5 mm. (Note that using a ruler marked in millimeters, you may be able to estimate to a 1/4 mm, i.e. 12.5 meters, which would allow you to estimate a location as being closest to, for example, 0, 12.5,  25, 37.5, or 50  meters; the accuracy of your measurementwill therefore likely be better than the intrinsic accuracy of the basemap.)
     Set SKPOLY to a value of 1, and the OSNAP mode to NODE  (ONSAP can be toggled On/Off by double clicking the OSNAP button on the tool bar at the bottom of the screen).
     Calibrate the basemap or the geological map (or attach and query a 1:20000 digital database), using the already plotted points as a template to provide the coordinates (no need to type in the coordinate values each time a calibration is carried out), or, attach the airphoto (or any other raster image, e.g. magnetic images) to the Autocad .dwg drawing file using  Insert -> Attach Raster image. In the latter procedure, when asked to do so, provide a rough estimate of the location of the bottom left hand corner of the airphoto, and drag the rubberband to create a rectangle that approximates the area of the photo. At this stage the placement of the photo does not have to be accurate. Then calibrate the photo to the locations on the location layer e.g. Glocation118, using the Rubber Sheet facility of Autocad Map (Map -> Utilities -> Rubber Sheet). Note, the first point entered will be the locality on the photo, the second point will be the corresponding locality on the location layer. It is also possible to attach a georegistered Spot, Landsat, or Radarsat (8 meter resolution) image to the drawing project, and use this image as a template to rubber sheet the airphotos. When rubber sheeting freeze all objects such as legends that do not need to be reoriented. Also, lock  (not freeze) the location points that you are going to use as reference points, otherwise they will be moved as part of the rubber sheeting reorientation. (Need to redo Map1 rubbersheeting!!!).
 
     Use the Autocad SKETCH or PL (polyline) functions to copy geological boundaries, faults, water bodies, etc, to the corresponding layer in Autocad Map (e.g. Geolgabbro2491 = gabbro unit on geology map 2491.)

     You are now ready to add data to Fieldlog, and to learn how to plot and draw 'heads up' maps in Autocad.