Differences

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--- examples [2019/12/05 18:00] – Listing the default rainbow colour values tarquinwj
+++ examples [2023/07/10 03:38] – [Colour Palette Scales - Lookups] brucemutton
@@ Line 432: / Line 432: @@
 **lookup altitude examples**
+The default automatic altitude colour bands take their highest and lowest values from the highest and lowest survey stations for the parts of the survey that are used in the rendering. It takes all the survey stations within the "cave" (ie. not in a "flags surface" section), from whichever surveys and subsurveys are going to be used in the rendering (if you are using a map, it will be whichever surveys and subsurveys have some of their parts included in that map), and finds the highest and lowest station. This happens even if the highest and lowest stations within those surveys are not even rendered because they are not included in a scrap.
+The legend will then be divided up into 7 numbers; the highest station, the lowest station, and 5 equally spaced values in between. These values are then rounded to the nearest integer when rendering (this rounding will also happen when displaying legend lookup values). This makes it quite possible that no scrap will ever be the colour of the highest and lowest stations, since scraps normally have more than one station in them, and the scrap altitude and colour will be taken from the average of those. The colour, as with lookup colours, will be faded the appropriate distance between the nearest colour values on either side.
+This also means that for a cave with very little vertical range, the default legend may show "10, 10, 11, 11, 11, 12, 12", when in actual fact, the numbers are all part way between 10 and 12.
+Using a lookup table allows you to take much more control, giving neater colour intervals (like one colour every 10 metres), or allowing the highest and lowest scraps to actually be the top and bottom colours.
   lookup altitude -title "Altitude legend"
@@ Line 442: / Line 450: @@
   endlookup
-It should generate red -> blue scale with desired values.
+It should generate red -> blue scale with desired values. Note that this is a linear fade with red at one end, blue at the other, and purple in the middle; it does **not** rotate the hue via orange, yellow or green in the middle.
 You may specify multiple lookup tables for same criterion using an index, ie  ":" separator in label
@@ Line 506: / Line 514: @@
 With maps you may specify colour of a particular map when selecting it your thconfig, without the need for a lookup
-  select map1 -color [100 0 0]  # This does not work for me.  Bruce
+  select map1 -color [100 0 0]
-Make sure you don't have any 'colour map-fg' statements however, as if present they will override [I THINK]
+TO DO: Add clarification as per 10Jul2023 forum post...