[Gnuplot-info] Gnuplot data file for contour plot

[Chelsea <cba...@bu...>]

Hi,

I am trying to make a contour plot.  I have a 3 column matrix for the x, y, and
z values.  The very first line in this matrix, however, says, 

Format: Log(10,s22th13) deltacp chi^2

The rest is a normal matrix, with the numerical values.
I am not sure what this line is supposed to do.  This data file was generated
using some sample code which I am trying to understand.  Is this line formatting
the data within the file itself?  The problem is, that when I try to make this
contour plot with a .gnuplot file I made, I get the error message:

warning: Axis range undefined due to improper data values.  NaN? Inf?

All points z value undefined.

I am not sure why I am getting this result.  It sounds like something is wrong
with the data file and I do not know what.

So I have these two questions:
1) What does the Format line mean?
2) Why do I have this error message?

If anyone can help, it would be much appreciated.

Thanks,
Chelsea

Here is the beginning of the data file

Format: Log(10,s22th13)   deltacp   chi^2
-4 0 99.257424
-4 4 95.835423
-4 8 92.976748
-4 12 90.669100
-4 16 88.905463
-4 20 87.684142
-4 24 87.008725
-4 28 86.887976
-4 32 87.335670
-4 36 88.370357
-4 40 90.015065
-4 44 92.296938
-4 48 95.246815
-4 52 98.898733
-4 56 103.289370
-4 60 108.457416
-4 64 114.442873
-4 68 121.286282
-4 72 129.027880
-4 76 137.706679
-4 80 147.359479
-4 84 158.019803
-4 88 169.716771
-4 92 182.473912
-4 96 196.307917
-4 100 211.227348
-4 104 227.231320
-4 108 244.308152
-4 112 262.434026
-4 116 281.571664
-4 120 301.669048
-4 124 322.658220
-4 128 344.454189
-4 132 366.953994
-4 136 390.035964
-4 140 413.559239
-4 144 437.363598
-4 148 461.269677
-4 152 485.079640
-4 156 508.578378
-4 160 531.535313
-4 164 553.706867
-4 168 574.839656
-4 172 594.674440
-4 176 612.950829
-4 180 629.412723
-4 184 643.814384
-4 188 655.927025
-4 192 665.545696
-4 196 672.496212
-4 200 676.641786
-3.96 0 92.964358
-3.96 4 89.530667
-3.96 8 86.652870
-3.96 12 84.317497
-3.96 16 82.516886
-3.96 20 81.249204
-3.96 24 80.518398
-3.96 28 80.334081
-3.96 32 80.711346
-3.96 36 81.670523
-3.96 40 83.236870
-3.96 44 85.440191
-3.96 48 88.314401
-3.96 52 91.897010
-3.96 56 96.228544
-3.96 60 101.351891
-3.96 64 107.311572
-3.96 68 114.152933
-3.96 72 121.921265


It continues like this.  The y column or "deltacp" always runs from 0 to 200 in
steps of 4 for a single value of x.