Step 1 Set up your data base table. I use four data fields to do this for each measurement type (foliation, lineation, strike-and-dip) in use in the project. In the table below, 'Attributes of Map.shp' the foliation field has the raw data as it is commonly recorded in the field. This field has a string format. The strike field is formatted as a number and it contains the azimuth direction of the foliation as seen with application of the right hand rule. Note that azimuth is reported as a negative number, this has to be done in order to accommodate the counterclockwise rotation of symbols in ArcView. The Dip field is also in number format and it contains the dip angle of the foliation. The adip field is in string format and also records the dip angle. This may seem a bit redundant but it serves a function later on as the Dip field is the classification field and the adip field is the label field. If you are working with more than one structural data type (foliations, lineations, joints) then name each field such that it has an unique name and has a name, which you can relate to. (folstrike, foldip, foladip, linstrike, lindip, linadip, etc.)
Step 2 Translate the raw data to usable values. Zero (0) is going to be used as a null value so for the first point (ID = 1) which has a due north azimuth; do not enter '0' into the strike field use instead '-360'. Note that for (ID=2) and (ID=3) both have the same strike as recorded in the field but each have a different dip direction. With application of the right-hand-rule N20E dipping 15 SE becomes azimuth 20 degrees dipping 15 degrees while N20E dipping 20 NW becomes azimuth 200 dipping 20 degrees. You must enter your azimuths as a negative value. For cases of inclined foliation like those of (ID=1,2,3,4,5) enter the dip angle unaltered in both the Dip and adip fields. Since (ID=6) has a horizontal foliation you must enter into the strike field the strike as -360 and into the Dip field the dip as 360 and leave the adip field empty. Treat vertical foliation the same as inclined foliation and give the dip as 90. If you have a field station in the database which does not have a foliation measurement (ID=8) then ArcView will insert zeros in the appropriate position in both strike and Dip fields. This may look like a big problem but it is not as long as you do not put anything in the adip field. The zero (0) gets used as a null signal.
Step 3 Linking Geopoetry to your ArcView symbol choices. Within the Font Palette window (see figure below) select the ABC button then run down the list of fonts on your machine until you have found and highlighted Geopoetry. Set the size to 24. Click on the Create Markers button.
Step 4 Assigning symbols to plotted data. First start a new theme with your data set, in the example case Map.shp. Make that theme active and double click on the symbol to go into the Legend Editor (see figure below). For Legend Type select Graduated Symbol. Hit the Classify... button and select 3 as the Number of Classes. For the Classification Field select your Dip field. Click the null button, the zero with a line diagonally through it. For the Field value select Dip and in the Null value box enter 0. In the Legend Editor main window edit the number in the Value field so that there are three classes, 1-89, 90 and 360 and edit the Labels to give the appropriate names, inclined, vertical, horizontal. Select the appropriate symbol type, size, and color for each class. Then hit the Advanced button. In the Rotation Field select strike. Check off scale symbols if you so wish. Now you are ready to hit the Apply button. Once you have done so the symbols appear on your map centered at the data site and rotated.
Step 5 Posting the dip angles. First go back to your Font Palette window and select a text font like Times Roman and select a font size smaller than the size you used for Geopoetry. Just leave that window alone now and make sure your View is active and that the appropriate theme is active. Go to the Theme pulldown and select Auto-label. In the label field select adip. Also check off "Find Best label Placement" and "Scale Labels". When you click the OK your map gets plastered with numbers that correspond to the dip angles. Before you do anything else print a copy of your map to verify that the symbols and the dip angles are of the size that you wish the final copy to be. If they are not then remove the labels, reset the sizes of the symbols and dip angles and reprint. Get it right before you proceed any further.
Now the fun comes..... you have to move each to where you really want it because ArcView does not generally put then where geologists like to have them and sometimes in maps with crowded data it is difficult to find which label goes to which symbol. Use your Pointer tool on the main tool bar to move things around. Save your Project frequently at this point!!!! The figure below illustrates the data described above and posted on a map. Note that point #6, the horizontal foliation, has no dip angle posted and also note that point #8, the station without a foliation measurement, has no symbol posted.
Step 6 Plotting more structural data on the same map. Open up as a new theme a second or third or forth copy of the same data table and repeat the above saving your project frequently along the way. You should work from the lowest positioned theme in the list to the uppermost as you progress. Lineations plot using lineation symbols, arrows. If a lineation was measured at the same station as a foliation the two symbols plot together such that the lineation arrow originates at the midpoint of the foliation symbol just as we geologists like it to be.
View the whole ArcView project described above arcview.jpg (big slow picture)
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This page has been created and is maintained by James A. Dockal of the Department of Earth Science of the University of North Carolina at Wilmington and
Blue Ridge Adventure Software
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