Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

Thread Subject:
How to make my graph smooth

Subject: How to make my graph smooth

From: Alex Jin

Date: 22 Mar, 2010 12:07:02

Message: 1 of 5

I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.

logo =

  Columns 1 through 5

           0 1521 1263 1190 1729

  Columns 6 through 10

        1715 1821 1726 1737 1799

  Columns 11 through 15

        1927 1860 1807 1749 1448

  Columns 16 through 20

        1543 1398 1415 1315 1297

  Columns 21 through 25

        1224 1252 1328 1283 1167

  Columns 26 through 30

        1304 1442 1524 1530 1623

  Columns 31 through 35

        1490 1430 1409 1512 1396

  Columns 36 through 40

        1371 1453 1601 1527 1273

  Columns 41 through 45

        1147 1218 1320 1381 1342

  Columns 46 through 50

        1290 1292 1431 1337 1333

  Columns 51 through 55

        1292 1279 1380 1299 1280

  Columns 56 through 60

        1403 1129 1103 1118 1223

  Columns 61 through 65

        1210 1061 1077 1227 1044

  Columns 66 through 70

        1216 1314 1274 1170 1153

  Columns 71 through 75

        1261 1263 1311 1221 1198

  Columns 76 through 80

        1312 1255 1299 1400 1447

  Columns 81 through 85

        1314 1284 1238 1138 1124

  Columns 86 through 90

        1271 1338 1221 1306 1309

  Columns 91 through 95

        1133 1120 1100 1274 1130

  Columns 96 through 100

        1121 1066 1176 1043 1171

  Columns 101 through 105

        1118 1183 1080 1077 1113

  Columns 106 through 110

        1037 911 951 961 1093

  Columns 111 through 115

        1003 1015 1134 1226 1143

  Columns 116 through 120

        1117 1099 1003 1109 1072

  Columns 121 through 125

        1132 1120 1071 1012 1166

  Columns 126 through 130

         927 1019 1039 1067 973

  Columns 131 through 135

        1041 1025 965 1002 1063

  Columns 136 through 140

        1098 1059 940 927 922

  Columns 141 through 145

         984 989 1003 987 914

  Columns 146 through 150

         898 1059 1163 1117 995

  Columns 151 through 155

        1183 1111 1056 1132 1178

  Columns 156 through 160

        1161 1184 1230 1062 1039

  Columns 161 through 165

        1043 1138 1098 1037 1028

  Columns 166 through 170

        1151 1040 1008 1136 1108

  Columns 171 through 175

        1047 887 1087 1047 1091

  Columns 176 through 180

        1028 1008 985 1085 988

  Columns 181 through 185

        1071 1065 1067 1080 995

  Columns 186 through 190

        1271 1058 1122 1013 1212

  Columns 191 through 195

        1142 1173 1112 1052 1105

  Columns 196 through 200

        1049 956 1008 956 980

  Column 201

        1006

Subject: How to make my graph smooth

From: us

Date: 22 Mar, 2010 12:17:05

Message: 2 of 5

"Alex Jin" <limyijin@googlemail.com> wrote in message <ho7mh6$8r0$1@fred.mathworks.com>...
> I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.

instead of simply and tediously copy/paste-ing thousands of useless, meaningless data points, tell CSSM this:
which sequence of ML commands have YOU come up so far to solve YOUR particular problem...

us

Subject: How to make my graph smooth

From: John D'Errico

Date: 22 Mar, 2010 13:34:07

Message: 3 of 5

"Alex Jin" <limyijin@googlemail.com> wrote in message <ho7mh6$8r0$1@fred.mathworks.com>...
> I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.
>

As us points out, this is meaningless data, without
the understanding that comes along with it.

There are many tools to do smoothing in matlab and
on the file exchange. You might do something as
simpel as convolve it with a gaussian, to blur it. That
is a completely valid smoothing technique.

Or you might use smooth, or supersmoother, or lowess.

http://www.mathworks.com/matlabcentral/fileexchange/17986

http://www.mathworks.com/matlabcentral/fileexchange/22470

Or use the splines toolbox tools, or my own slm tools.

http://www.mathworks.com/matlabcentral/fileexchange/24443

Or you might use a Savitsky-Golay tool. There are several
of them on the FEX.

What really matters though, is what you know about this
curve. That will drive your result, as well as the method
you might use to do the smoothing.

The one thing I would suggest avoiding, is polyfit. Do NOT
use polyfit for this!

John

Subject: How to make my graph smooth

From: Sadik

Date: 22 Mar, 2010 13:59:06

Message: 4 of 5

Hi Alex,

As an appendix to the rich set of smoothing options John has indicated: You could also use medfilt1 [or medfilt2 if your data is 2D].

Best.

Subject: How to make my graph smooth

From: John D'Errico

Date: 22 Mar, 2010 14:11:05

Message: 5 of 5

"Sadik " <sadik.hava@gmail.com> wrote in message <ho7t3a$3ps$1@fred.mathworks.com>...
> Hi Alex,
>
> As an appendix to the rich set of smoothing options John has indicated: You could also use medfilt1 [or medfilt2 if your data is 2D].
>
> Best.

Good additions there. There are many tools to be found.
Knowing your problem, your data, and knowing what
are your goals for this are all important things before
you start.

A very important part of this is knowing the noise
structure in your data. If the noise can be assumed to
be random, uncorrelated, and normally distributed, then
you would use a different tool than if your noise has
other structure to it.

John

Tags for this Thread

No tags are associated with this thread.

What are tags?

A tag is like a keyword or category label associated with each thread. Tags make it easier for you to find threads of interest.

Anyone can tag a thread. Tags are public and visible to everyone.

Contact us