Extracting matrix and making 2D plot

I made 2-D color map by using those datasets below

• latmat.mat... latitude data (171*171)
• lonmat.mat...longitude data(171*171)
• CH4.mat.... CH4 emission data (171*171)

Coding is as follows,

figure
latlim=[min(latmat(:)) max(latmat(:))]
lonlim=[min(lonmat(:)) max(lonmat(:))]
ax=usamap(latlim,lonlim);
title('Air Pollution Map');
surfm(latmat,lonmat,CH4)

states=shaperead('usastatehi',...
    'UseGeoCoords',true,'BoundingBox',[lonlim',latlim']);
geoshow(ax,states,'FaceColor','none')
contourcbar

And got this figure below.

However, I would like to make a map within those ranges below.

70W<Longitude<75W

40N<Latitude<43N

How can I extract the datasets and make a colormap?

Answer 1

[Krishna Zanwar]

You can change the limits by replacing

latlim=[min(latmat(:)) max(latmat(:))]
lonlim=[min(lonmat(:)) max(lonmat(:))]

by

lonlim=[-75 -70];
latlim=[40 43];

I have attached the output of the graph below.

Hope it helps.

[Chihiro Omori]

Thank you for your answer! That is what I actually needed!

I have one more question.

How can I extract the emission dataset from the matrix ?

For example, I would like to extract CH4 emission data in the range of ...

• lonlim=[-75 -70];
• latlim=[40 43];

and make a matlab matrix file like CH4.mat.