1 | ;+ |
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2 | ; |
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3 | ; @file_comments |
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4 | ; We give a min and a max, and the procedure send back |
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5 | ; the good contour interval and labels's value. |
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6 | ; |
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7 | ; @categories |
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8 | ; Graphics |
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9 | ; |
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10 | ; @param MIN {in}{required} {type=float} |
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11 | ; above what value we want to trace a contour |
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12 | ; |
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13 | ; @param MAX {in}{required} {type=float} |
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14 | ; below what value we want to trace a contour |
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15 | ; |
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16 | ; @param CI {out} {type=real} |
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17 | ; the contour interval. Use it in <proidl>CONTOUR</proidl> with the |
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18 | ; keyword LEVEL. |
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19 | ; |
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20 | ; @restrictions |
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21 | ; CI is a multiple of the unity in unity log of 10. |
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22 | ; It force the number of contours to be even. |
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23 | ; |
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24 | ; @history |
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25 | ; G. Roullet / aout 99 (gr\@lodyc.jussieu.fr) |
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26 | ; |
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27 | ; @version |
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28 | ; $Id$ |
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29 | ; |
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30 | ;- |
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31 | ; |
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32 | PRO autoscale, min, max, ci |
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33 | ; |
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34 | compile_opt idl2, strictarrsubs |
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35 | ; |
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36 | ; Estimation of a first CI, notice the presence of the floor (Inferior round) |
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37 | ; This CI is a multiple of the unity in unity log of 10. |
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38 | ci = (max-min)/20. |
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39 | ci = 10.^floor(alog10(ci)) |
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40 | |
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41 | n = 0 |
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42 | ci0 = ci |
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43 | ; |
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44 | coef = [2, 2.5, 5, 10] |
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45 | ; |
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46 | ; We test differents CI (contour intervals), i.e. 1, 2, 2.5, 5 and 10 |
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47 | ; until the number of contour is inferior to 30. |
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48 | ; |
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49 | WHILE ceil((max-min)/ci) GE 30 DO BEGIN |
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50 | ci = ci0*coef[n] |
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51 | n = n+1 |
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52 | ENDWHILE |
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53 | |
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54 | min = floor(min/ci/2)*ci*2 |
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55 | max = ceil(max/ci/2)*ci*2 |
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56 | |
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57 | nlevels = round((max-min)/ci) |
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58 | |
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59 | ; |
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60 | ; We force the number of contour to be even |
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61 | ; |
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62 | IF nlevels MOD 2 EQ 1 THEN BEGIN |
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63 | nlevels = nlevels+1 |
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64 | max = max+ci |
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65 | END |
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66 | END |
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