How do I remove the color from the Arabian plate

Hello all,
Please, I plotted surface map of Africa Plate, and I don’t want the color to show in the Arabian plate, (I want Arabia to be white). How do I go about please. Glad to be help out.
here are my codes, data and the plot (I am using GMT 6.1.1)

gmt begin Africa_Net pdf

gmt set MAP_FRAME_TYPE plain
gmt set FONT_LABEL 15p
gmt makecpt -Cjet -T0/10
 gmt pscoast -bi2f -R-30/65/-40/40 -EAF -JM20c -BWSne -Baf -I1/1p,0/200/251 -W1,black -Gwhite -Di -N2/0.25p,black -Na/0.5,black -Swhite
 gmt coast -Wthinnest,black -Lg55/3+jBR+c20+l+f
 	gmt surface try.dat -Gsurface.GRD -T0.5 -I0.01 -R-30/65/-40/40
gmt grdimage surface.GRD -Q -C
gmt coast -Ir/grey -Wlightgrey -Swhite  -N1/darkgrey

gmt plot try.dat -Sp0.25 -C -W1,black

gmt colorbar -Dx4c/5c+w4c/0.3c+jTC+h -Bxa2f0.5+l"Amplitude [mm]" -C

gmt end show
#Long Lat Ampl Up
30.0897 -1.9446 1.847339595
20.8109 -32.381 3.798018136
17.0894 -22.575 3.09797482
47.2292 -19.018 4.756496116
38.7663 9.0351 3.062711177
2.45 6.3847 4.171005109
23.9926 -30.665 3.846470302
-16.907 32.6479 3.865549128
27.7072 -25.887 3.385039997
19.2231 -34.425 4.315094529
-17.894 28.764 1.04839766
30.7379 -0.6015 0.623763817
25.54 -25.805 3.177390843
28.224 -25.746 3.386948617
28.224 -25.746 3.414682926
-6.8543 33.9981 3.693086527
32.0784 -28.796 3.538920908
36.8935 -1.2208 0.77174576
17.8792 -29.669 3.713477937
55.4794 -4.6737 5.801116598
-6.2056 36.4643 5.46289739
30.384 -23.079 3.106941915
31.4209 -28.293 3.283776438
28.6725 -31.549 2.016177825
-5.2401 6.8706 5.329711906
28.311 -15.426 6.043142664
-2.9516 35.2812 6.165427079
70.2555 -49.352 2.560330917
55.4794 -4.6737 0.591714584
37.861 -46.876 7.512376514
163.19 -77.034 2.568617945
40.2002 -10.269 4.246254674
46.7933 -21.906 3.79775589
35.29 0.2883 1.306937821
-22.935 16.7321 2.080800831
-17.44 14.7212 1.883997078
37.3291 11.5691 6.629961175
51.8555 -46.432 4.211655847
28.224 -25.746 5.019772272
28.224 -25.747 5.060090725
55.4795 -4.6737 3.900999836
166.758 -77.849 2.876297468
161.998 -77.805 2.137582028
37.8095 8.9921 5.781003221
37.5609 6.0624 2.573442074
42.6544 13.0629 2.087266201
37.3597 11.5998 5.901427544
40.7084 7.146 1.393122458
39.5894 5.3347 0.742964825
40.0261 7.1134 5.635598027
37.022 12.5116 6.39541631
39.054 15.8534 2.873783763
38.9881 11.9851 6.150545228
26.716 -30.679 4.11541614
26.2978 -29.103 1.346413614
27.4291 -32.863 2.660206473
27.7766 -25.636 3.927001838
28.7327 -25.803 3.683885872
18.4897 -34.353 3.390695025
26.5072 -33.320 3.302809507
24.5345 -32.248 3.065716444
28.3729 -26.509 3.689929272
27.686 -25.890 3.375044611
30.0688 -30.146 1.189372984
24.8065 -28.743 4.258840044
23.4325 -27.461 4.582954596
29.4221 -30.565 2.667167221
27.7663 -26.083 3.650262504
27.2401 -27.664 4.302790895
18.7308 -33.464 7.724737972
29.4542 -25.774 2.702783384
29.9874 -29.209 3.751660651
30.9752 -25.475 3.612531701
28.406 -24.703 3.749787195
26.7381 -26.934 1.062618156
23.367 -34.055 3.160567783
28.9302 -24.013 3.18832941
28.2826 -25.732 4.826388947
22.7493 -29.668 4.013944891
29.4657 -23.923 4.443373
30.7545 -30.286 3.088282485
31.2898 -29.344 4.721434734
20.8105 -32.380 3.166588536
26.7375 -27.978 4.146867964
19.445 -33.645 5.37587827
28.3413 -26.195 3.760312196
28.3342 -28.249 3.1446908
19.762 -31.482 3.826904397
18.4685 -33.951 5.029136966
30.9467 -29.965 1.362952145
27.8286 -33.038 5.128040542
27.6961 -23.687 3.64543245
29.4121 -25.162 3.554123253
30.5776 -29.071 6.64574804
18.1578 -32.973 4.618556733
29.7815 -28.558 3.175668678
31.1343 -23.952 3.289603467
25.611 -33.985 3.690802234
27.9038 -26.661 3.558072306
22.5736 -32.347 3.796349115
29.9838 -26.498 2.790313624
38.9103 15.3397 8.132652171
29.8934 0.3504 2.413589832
37.3597 11.5998 5.801320277
2.0005 7.1823 5.269854418
2.928 11.1247 6.072708198
1.3807 10.2532 3.906415405
2.6257 9.3575 5.325669424
1.9932 7.9278 6.566064504
33.263 -9.7013 5.178669479
40.358 12.6437 16.45994425
40.3174 12.0681 8.24520056
39.4827 13.4809 6.71378095
42.0339 9.4228 1.0489091
32.4449 0.0382 2.04007701
38.7628 9.0199 6.433450004
41.8583 9.6131 5.496708303
35.1025 -9.5468 8.397915219
34.1071 -10.614 6.747603958
34.8003 -11.274 10.33187671
33.4592 -8.9118 7.539247734
36.4206 -7.544 4.808123124
34.0059 -11.425 6.892378945
35.6728 -10.689 9.644322021
33.5764 -16.147 5.169605108
-5.363 35.5616 4.252435771
33.5744 -11.175 7.962730284
35.3251 -15.376 4.397944416
-5.1255 33.5139 4.685734018
34.5847 -9.592 14.81559655
23.5284 -19.902 5.371787033
23.1507 -15.254 9.248773284
26.0157 -15.747 11.1243546
21.2559 -28.414 3.887837194
30.3832 -29.601 4.417364457

file:///home/gfz/2020-unavco-course/2020-unavco-course/grids/Africa_Net.pdf

Hi parker.

Please check. We can see the figure.

Does the table correspond to the Arabian Plate? It’s name is try.dat, right?

here is the plot. try.dat is what I used in saving it. the Table does not correspond to Arabia Plate only Africa Plate

Thanks.
So, you have a table a data, make a grid with surface and them plot the grid.

Do you have a polygon of the Arabian plate? If so, you could used it to paint over the grid.

I don’t have the polygon of Arabia plate, Please how do I get the polygon sir. Hope to hear from you
Thanks and kind regards

Usifoh Saturdasy

I think you could find it on internet.

Or maybe you can draw your own polygon in any GIS.

Okay sir, I will draw mine. Thanks for your assistance

You could use Bird (2003); see http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm.