Incomplete contour map - Current is not filling the plot

clear all
close all
clc

load contour_data.TXT
data = contour_data;
long = data(:,1);
lat = data(:,2);
ba = data(:,3);

figure(1); plot(long, lat, '*k');

n = length(lat);
[X,Y] = meshgrid(linspace(min(long), max(long), n), linspace(min(lat), max(lat), n));
Z = griddata(long, lat, ba, X, Y);
figure(2)
contourf(X, Y, Z);
hold on 
plot(long, lat, '.r');
grid
h= colorbar
title(h,'Bouguer anomaly (mgal)')
xlabel('Latitude');
ylabel('Longitude');
title('Bouguer anomaly variation');
%colormap(surf);

% DATA, incase it has not been included: 

-4.124347462	52.82254067	-2.414442531
-4.121829386	52.81625525	-2.07190912
-4.119095882	52.81894779	-2.05316106
-4.116335235	52.81772917	-1.169505182
-4.115900384	52.81794375	-1.079339138
-4.113533702	52.81933475	-0.351271015
-4.112325438	52.82012959	0.032004673
-4.111193938	52.82036554	0.683608536
-4.111386301	52.82035313	0.654947439
-4.109294741	52.82038133	1.13485928
-4.108993812	52.81999103	2.601458499
-4.107647756	52.81978115	4.801204286
-4.107111151	52.82034819	5.925406343
-4.106585451	52.82083411	6.608399805
-4.106227717	52.82111023	7.068829607
-4.105947667	52.82115116	7.081235979
-4.104789113	52.82113575	7.796179819
-4.104716695	52.82117301	7.9311538
-4.103943021	52.82052131	8.233178042
-4.103130443	52.82029293	8.471102473
-4.102463576	52.82000801	8.673152696
-4.102197059	52.82002172	8.736696721
-4.101093089	52.81990639	9.144135788
-4.099969193	52.81537628	11.55173962
-4.099562504	52.81987054	9.420156658
-4.099161645	52.81986864	9.666638669
-4.099237964	52.81991225	9.60283148
-4.099502544	52.82047408	9.879058905
-4.098441653	52.82063672	10.1927144
-4.098300704	52.82079207	10.04424085
-4.097271193	52.82099012	10.37724621
-4.096294509	52.82105234	10.4346074
-4.095269438	52.82103448	10.54741082
-4.094030684	52.82089449	10.55380828
-4.092506696	52.82068758	10.71325178
-4.088859062	52.82014938	10.95086924
-4.074187673	52.82531643	11.67943616
-4.073324667	52.82496283	11.96719508
-4.066020099	52.82463164	13.09733926
-4.07383624	52.82417158	11.84273101
-4.074087813	52.82384347	11.18743497
-4.074530488	52.82347605	12.31061911
-4.074598503	52.82303425	11.34996378
-4.074516639	52.82287382	11.48457785
-4.074748507	52.82213242	10.87278665
-4.07403116	52.82140761	10.46084367
-4.072815843	52.82144683	10.56342211
-4.071918823	52.82162436	11.62624915
-4.070843514	52.82211071	10.59852273
-4.06942332	52.82283687	12.18746865
-4.068855548	52.82307158	10.33754713
-4.068855548	52.82307158	10.85594026
-4.068185227	52.82333504	8.770418049
-4.066589518	52.82411817	8.288771725
-4.053847156	52.82022106	3.924714143
-4.053349258	52.81973511	11.37666469
-4.052661535	52.81931539	10.92556862
-4.052431883	52.81885178	10.43691376
-4.050813264	52.81820536	10.79877796
-4.049629814	52.81797403	12.00768717
-4.048634908	52.81796424	11.85617273
-4.047984946	52.81771469	11.35760844
-4.047205887	52.81661312	11.66852885
-4.046762305	52.81633303	11.29025884
-4.043145225	52.8157929	10.44212971
-4.043005435	52.81566043	11.46957275

I am currently creating a contour map for gravity data (Bouguer anomalys), and I cannot seem to fill the entire figure. Hoe do I extrapolate the contours to fill the figure?

I don't want any white areas on my picture.

Hopefully my data has been included

Answer 1

[Harshit Jain]

By executing your code I can see that there are many 'NaN' values in the "Z" matrix. Hence, as a result, that points on the contour map are not plotted. You can try replacing 'NaN' values with some finite value and it will work. This link will help.