CARTPT.BAS DOCUMENTATION  rev 11/15/87 

          NOTE: Additional features and refinements have gradually been 
          added to CARTPT over the past 2 years (mainly to suit my own 
          requirements)   and are being incorporated into v11/15/87.  
          Below is updated documentation.  

               The CARTPT program is a quick way of reviewing data in the 
          form x,y by plotting in Cartesian (rectangular) coordinates. The 
          user is given a choice of LINEAR, LOG Y, LOG X, and LOG LOG 
          scales (popular graphpaper formats).  Data can be entered from 
          the keyboard (normally used only for small quantities of data) 
          or from a RAM or CAS file (containing only numerical data in the 
          form x1,y1....xn,yn).  The RAM file is preferrable becaues it 
          allows the user to return and replot in different scale formats 
          without re-entering data.  Additionally, both the RAM or CAS 
          files can serve as a form of interface between this program and 
          data generated by any other user program.  

               Menus are presented to allow selection of the following 
          options (* indicates new feature of v11/15/87): 

          Scales: Linear, Log, or semilog.  

          Scaling*: The program automatically scales the data to utilize 
          the full screen size of the Model 100, however the user is now 
          offered the option of bypassing autoranging to specify the 
          actual X and Y ranges that are to be plotted.  Please observe 
          the following when utilizing manual ranging: 

               1) User must specify valid ranges (specifing a range that 
               covers 0.0 or negative values in a log scale for instance 
               will abort with an error. 

               2) If option 2 (points connected by line) is selected and 
               scales are manually selected so that one point is off the 
               screen, the lines will not be drawn to connect that point 
               but no error will be generated. 

          Gridlines*: User now has the option to insert a grid of choice 
          in the X and/or Y scales.  Reply Y when prompted, you will be 
          asked the value of the first gridline and the increment 
          (spacing) in both directions.  Simply hitting [enter] for these 
          values will cause no gridlines to be drawn in that direction. 

          Input: Keyboard or File.  In the file input mode, opportunity is 
          provided to add a second set of data points for comparison.  To 
          prevent visual confusion it is best to use this with the points 
          connected by a line output (see below).  

          Output: Plot can consist of points, points connected by line, or 
          histogram style (bar) chart.  Provision is made for user 
          installation of appropriate screen dump routine. 


               [F1] to dump screen to a printer.  NOTE: The actual screen 
               dump routine is replaced in this copy (at line 63000) by a 
               simple dummy RETURN.  A variety of screen dumps are 
               available on CIS for various printers; see notes below. 







               [F2] to return to scale selection menu for different scales 
               (this function is available for file entered data only).  

               [F3] gracefully exits the program and clears HIMEM 


          Notes:  

               1) If the POINTS CONNECTED BY LINE option is selected, 
               additional time is required for sorting values into 
               sequence, so a delay will be noticed if there are many data 
               points.  In cases where the X values are already in 
               ascending or descending order, answering "Y" to the prompt 
               "is this data sequential?" will bypass the sort and speed 
               up the operation.  

               2) If a 2nd curve is plotted, it can have as many or fewer 
               data points than were specified for the first curve.  Since 
               screen scaling is determined by the first data set, choose 
               the data with the widest range or most important range as 
               data set #1 or select the range manually.  When prompted 
               for the number of data points, specify the larger of the 
               two sets, unused points will be ignored.  

               3) Screen dumps--No screen dump is included withthis file 
               because printers vary so much.  I personally use two 
               different printers with totally different formats, so for 
               my use, I keep the program without a dump and merge the 
               appropriate format when ready to use it.  To create a merge 
               file; select a screen dump for your printer (a wide variety 
               is available on CIS).  For line 2, specify any special 
               operations (CLEARing, initialization, LOADM or GOSUBS which 
               must be called) which must be performed at the beginning of 
               the program.  Set DR$=[printer name].  Any routine you use 
               must be accessable by a GOSUB 63000 instruction.  If your 
               dump is in BASIC, be sure also that the variable names used 
               in the dump do not conflict with those in the program.  
               Below is an example of a simple merge file which enables a 
               machine language screen dump kept as a RAM file SCRDP2.CO: 

               2 CLEAR256,62628:LOADM"SCRDP2.CO":EX=62636:DR$="LPVII"'execu 
               tion address 
               63000 CALL EX:RETURN 'LPVII DRIVER MERGE PROGRAM FOR CARTPT 

               Remember, this is simply an example, the exact merge file 
               would be determined by the type of screen dump being used. 


          Judging from Email inquiries and comments, this is possibly one 
          of the more used programs that I have uploaded. I hope this is 
          even more useful.  If your have any further comments, contact me 
          via Email:  

          Jay Holovacs, 74756,413