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--- internal:administration:idl [2025/11/25 14:42] – [symboltypes] jan
+++ internal:administration:idl [2026/03/19 20:55] (current) – [contour] jan
@@ Line 8: / Line 8: @@
 IDL current reference @ NV5 Geospatial software :\\
-[[https://www.nv5geospatialsoftware.com/docs/routines-1.html| IDL  8.9. Reference @ NV5 ]]\\
+[[https://www.nv5geospatialsoftware.com/docs/routines-1.html| IDL  Reference @ NV5 ]]\\
-[[https://www.nv5geospatialsoftware.com/docs/funclisting.html| IDL  8.9. funclisting @ NV5]]\\
+[[https://www.nv5geospatialsoftware.com/docs/funclisting.html| IDL  funclisting @ NV5]]\\
-[[https://www.nv5geospatialsoftware.com/docs/WhatsNew.html| IDL  8.9. whats new @ NV5]]\\
+[[https://www.nv5geospatialsoftware.com/docs/WhatsNew.html| IDL  whats new @ NV5]]\\
@@ Line 285: / Line 285: @@
   IF x eq 4 THEN BEGIN
     print, 'x equals 4' $
-  END ELSE BEGIN
+  ENDIF ELSE BEGIN
     print, 'x is not 4'
-  END
+  ENDELSE
+to keep track of your blocks you may extend the END statements with the statement the block started with, i.e. ENDIF for the block started afer an 'IF' or ENDELSE or ENDCASE, ENDWHILE, etc.
+The interpreter tells you then if a ENDxxx statement does not fit.
+You may nest i.e. build structures like IF ... THEN ... ELSE IF ... THEN ...\\
+Alternatively you use the CASE statement:
+  CASE x of
+: <>
+: BEGIN
+        ...
+        END
+    ELSE: BEGIN
+          ...
+          END
+  ENDCASE
+if you want to handle several cases of x in one block you can do this:
-for safety you may extend the END statements with blocked statement i.e. ENDIF or ENDELSE
+  CASE 1 of
+     x eq 1: begin
+       ...
+        END
+    (x eq 22) OR (x eq 23): begin
+        ...
+        END
+    ELSE: begin
+          ...
+          end
+  ENDCASE
-you may nest i.e. build structures like IF ... THEN ... ELSE IF ... THEN ...
-or use the CASE statement.
 Loops can be implented with FOR, WHILE or REPEAT as one-liners:
@@ Line 308: / Line 336: @@
   FOR i = 0,5 DO BEGIN
     PRINT, i
-    END
+    ENDFOR
   i = 0
@@ Line 314: / Line 342: @@
     i = i+1
     PRINT, i
-    END
+    ENDWHILE
   i = 1
@@ Line 320: / Line 348: @@
     i = i + 1
     PRINT, i
-  END UNTIL i gt 5
+  ENDREP UNTIL i gt 5
 to make coding a bit safer you may append the name of the loop command to the END statement, i.e.
@@ Line 327: / Line 355: @@
   ENDREP
-a PROCEDURE is a subroutine that may take parameters and change them. Its definition is started with the word PRO and ends with a END statement
+a PROCEDURE is a subroutine that may take parameters and change them. Its definition is started with the word PRO and ends with an END statement
   PRO my_proc, text_str, x_value=x_value
@@ Line 3043: / Line 3071: @@
   extrm_lev_max = +(machar()).xmax
-See function [[https://www.harrisgeospatial.com/docs/machar.html|function machar]].
+See function [[https://www.nv5geospatialsoftware.com/docs/MACHAR.html|function machar]].
@@ Line 3059: / Line 3087: @@
     /overplot
-Keyword c_annotations is used here toprovide a format - this is usually not necessary.
+Keyword c_annotations is used here to provide a format - this is usually not necessary.
 You can define also different thicknesses, colors etc. with the other %%c_...%% key words of %%contour%%
 see [[http://www.physics.nyu.edu/grierlab/idl_html_help/C40.html#wp908085| help for contour]].
+=== line patterns ===
+contour can draw hatch patterns - but note: the pattern is not transparent.
+  contour, z, x, y, $
+    levels = levels, $
+    c_orientation = [ 0 , 22, 45, 90, ... ] , $ ; orientation of the lines in degrees
+    c_spacing = [ 1, 0.5, 0.25, ... ] ; spacing between lines in cm
+=== Path of contour lines ===
+contour can provide the pathes of the contour lines:
+  contour, z, x, y, $
+    levels = levels, $
+    path_info = path_info, $ ; info about the provided pathes (see below). If you provide here a variable contour will not draw.
+    path_xy = path_xy, $ ; variable for coordinates: fltarr(2,N_tot)
+    /path_data_coords, $ ; want to have data coordinates in data_xy instead of normalized coo's.
+    /path_double, $ ; you need double if eg x is time as julian day
+    /overplot ; avoid contour to rescale the axes - if you already had a plot or contour plot you want to reuse
+path_info is an array of CONTOUR_PATH_STRUCTURE. The number of elelemtns gives the number of sub pathes.
+Elements %%offset%% and %%N%% give the starting index and length of every isoline in path_xy.
+You can then use the pathes in poly_fill to do transparent hatch patterns:
+  for i = 0, n_elements(path_info)-1 do begin
+    path_info_i = path_info[i]
+    ii = path_info_i.offset + lindgen(path_info_i.N)
+    polyfill, path_xy[0,ii], path_xy[1,ii], /line_fill, spacing=0.7, orientation=i*5, noclip=0
+  endfor ; i
+You could also use polyfill to put a byte pattern or wrap an image between the isolines ...
 === color bar ===
-You can use contour also to make a **color bar**:
+You may want to have a color bar setting the colorshading in relation to values.
+You can use contour to make a **color bar**:
 A **horizontal** color bar at the bottom