Outputting Point Data to IDRISI to create a VECTOR image of location points

    (File: \aacrse\505\acad\acad2id2.rtf)

     You must know the DOS ‘cd’, ‘delete’, ‘copy *.*’, ‘rename’ commands.
     Create a subdirectory flyourinitials or delete all the files in flyourinitials if this subdirectory has been used before in some other exercise.
     Copy all the files in the snowemp2 directory to flyourinitials (COPY c:\snowemp2\*.*  c:\flyourinitials). (The files 200av3n.dat and 200bv3n.dat will be included in the transfer with the snowemp2 database files.)
     (‘SNOWEMP2’ is similar to ‘SNOWEMP’ except that a ‘Lithnum’ and a ‘Metals’ field have already been added to the LITH Table, and a ‘Lithnum’ numerical code added as the last field in the input file 200bv3n.dat . The fields in the STATI table have been reorganized to allow output of a file containing GRIDX, GRIDY, and STATUM; ‘stati’, ‘litho’, ‘plot’, and ‘txt’ QUERY macros have been written into QUERY; and the palette parameters (size, offset, etc) for the fields of interest in the plotting procedure have also been modified .)
     1) Load Autocad and Fieldlog;
     2)  make a ‘flyourinitals’ map projection’
     3) select it as the map projection to be used in Map Project setup (make sure you select your USER PROJECTION ‘flyourinitials’, otherwise Fieldlog will output the coordinates as UTM values).
     4) Set your projection as the projection to be used in ‘Points’ in the Tables setup for STATI;
     5)  import 200av3n.dat (GRIDX, GRIDY, STATNUM, STATYPE, AND TRAVNUM) into the STATI Table, and 200bv3n.dat (STATNUM, LITHCODE, ROCKTYPE, METALS, LITHNUM) into the LITHO Table. Check the tables with ‘QUERY’.
     Use QUERY to run the ‘txt’ query, and in the PLOT menu click TEXT. Select ‘GRIDX’,  ‘GRIDY’ (the coordinates of the feature) and  ‘STATNUM’ (the geographic definition feature Code), in that order, as the fields to output as a VECTOR GEOGRAPHIC DEFINITION file. Select ‘space’ as the Column (Field) Delimiter (that is, leave the Field Delimiter box empty), click the projection box to select your projection,  and name the output file ‘c:\flyourintials\yourintialsxyz’ (NO EXTENSION; Fieldlog will automatically add the ‘.txt’ extension, and NO ‘fl’ prefix for the file name), and save it to your directory.
      Repeat this procedure to output a file composed of the fields ‘STATNUM’ (geographic definition feature code) and ‘LITHNUM’ (the numerical attribute value for the rock type). Name the file ‘c:\flyourinitials\yourinitialsstz’. (NO EXTENSION; Fieldlog will automatically add the ‘.txt’ extension).
     Use the Autocad ‘SHELL ENTER ENTER’ command to get to DOS.
     Change to your subdirectory, and check the files with DOS EDIT (You MUST know the DOS ‘cd’, ‘edit filename’ and ‘rename’ commands).
      Rename the file ‘yourinitialsstz.txt’ to ‘yourintialsstz.val’.
     Type ‘Exit ENTER’ at the C: prompt to return to Autocad.
      Logoff , unload Fieldlog, and exit Autocad.

     Load IDRISI and set the environment to your directory ‘flyourinitials’. Run the module XYZIDRIS in ‘FILE-IMPORTS’ to convert the ‘yourinitialsxyz.txt’ file to a  ‘your initials.vec’ vector file. Check the ‘yourinitials.dvc’ document file - click FILE on the menu bar and then DOCUMENT. Click the ‘Vector’ button and double click the ‘File to Document’ box. Double click the file in the ‘Pick File’ list, and if necessary fill in the vector documentation file (Title - ‘yourinitials’, ID type -Real, File type - Binary, Object type - Point, Reference system - Plane, Reference units - Meters, Min X - 0 (12), Max X - 100 (80), Min Y - 0 (19), Max Y - 100 (87), Unit distance - 1; the values in parenthesis are the actual values calculated by Idrisi in the conversion of the xyz file to the vec file).
      Make a ‘your intitials.dvl’ document file (e.g. wrc.dvl) for your ‘yourintialsstz.val’ values file. If Idrisi says it can’t find a ‘yourinitialsstz.val’ document file, click OK, and fill in the Document menu that will appear on the screen. Use ‘Ascii’ for file type, ‘31’ for Records, ‘2’ for Fields, ‘Integer’ for Data type, ‘1’ for Minimum value, and ‘4’ for Maximum value. The Field 1 and Field 2 boxes will be filled in automatically by IDRISI.
     The vector file can now be displayed by selecting Display Launcher in the DISPLAY menu, then clicking the ‘vector’ button, double clicking the ‘Name of File to Display’ box to select your file (double click the file name), and then the OK button. An image will be displayed showing the stations as a set of red dots. (Check the ‘idrpnts’ standard symbol palette. Then redisplay using the ‘qualitative 256’ point symbol palette.) Note that the attribute attached to the points is the STATNUM Geographic identifier, and serves only to relate the point’s location to its attributes in the Attribute values files.
 Next DISPLAY the vector file  using the Attributes value file with the ‘qual16’ palette. The points will now be displayed in a colour corresponding to their rock type attribute value.

 To convert a VECTOR image to an interpolated RASTER image

     To generate an interpolated raster image, select in sequence ‘DATA ENTRY’, ‘SURFACE INTERPOLATION’, and ‘INTERPOL’. Enter the ‘Input Vector File’ name (e.g. ‘yourintials’; NO extension) and the ‘Output file name’ (e.g. ‘yourinitials’; NO extension). Enter a distance weight exponent of 6. Click the ‘Use a values file for height’ box and enter the name of the values .VAL file (e.g. ‘yourintials’; NO extension). Enter ‘Columns’ as 512 and ‘Rows’ as 512, and ‘m’ for ‘Value units’. The Min-Max values should be entered automatically. Examine the raster image using the Display Launcher option in the DISPLAY menu, and selecting the Idrisi256 pallette and Autoscaling. Note that since there are only four attribute values, the colour for each value will correspond to multiples of 64 in the Idrisi256 colour spectrum. Try using other palettes.
     Generate an interpolated image as above, but select the ‘Use Vector Point ID’s as heights’ option.
     Try to understand the relational significance of the vector geographic definition file and the complementary attribute values file. What is an ‘attribute’?

     IDRISI provides no drawing tools that will allow you to add objects to an existing vector image. It is possible however to trace lines on a raster image onto a defined vector image using the digitizing tool (red cross in a yellow filled circle). Read the IDRISI help file on the subject of ‘Digitize’.