CODEWITHSUNDEEP
matlabmatrixsubset
Dave
Dave

Reputation: 3208

Matlab, How to retrieve subset of data from a Matrix which satisfy a specific condition

so I'm trying to do some data processing in matlab, but i'm having issues with filtering out the data that I need.

So the data I have is in the format. 

data1 = [time1, time2, time3, time4, time5, time...]
data2 = [d1, d2, d3, d4, d5, d....]
data3 = [latitude1, latitude2, latitude3, latitude4, latitude5, latitude....]
data4 = [longitude1, longitude2, longitude3, longitude4, longitude5, longitude...]

Whereas all the data in each column is related. And each row has the same number of elements.

What I want to do is filter out data that does not fit within a certain latitude and longitude.

So my thoughts are to turn these all into a matrix, 

matrix1 =[data1;data2;data3;data4]

giving something like:

[ time1, time2, time3, ...]
| d1,    d2,    d3,    ...|
| lat1,  lat2,  lat3,  ...|
[ lng1,  lng2,  lng3,  ...]

and then to write something that will delete a column if element in data3 and data4 don't meet the condition of being within this lat/lng boundary.

pseudo-code ie: 

if(!data3.entry.isInRange(latrng1,latrng2) || !data4.entry.isInRange(lngrng1,lngrng2)){
deleteCurrentColumn;
}

So for example if lat2 or lng2 is out of bounds the matrix would then be transformed into:

[ time1, time3, ...]
| d1,    d3,    ...|
| lat1,  lat3,  ...|
[ lng1,  lng3,  ...]

How could I go about making something similar to the above pseudocode work in Matlab? My end goal is to organize/filter the matrix by location bounds.

Any help is appreciated! Thanks!

Upvotes: 1

Views: 170

Answers (1)

beaker
beaker

Reputation: 16791

You would create a logical array of the columns that meet all of the criteria:

inRange = (data3 >= latrng1) & (data3 <= latrng2) &...
          (data4 >= lngrgn1) & (data4 <= lngrng2);

Then use that as a column index into matrix1:

filteredMatrix = matrix1(:, inRange);

Upvotes: 2

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