How to view a shape file in matlab

Hello,

I have a .shp file of the country Ireland.

This is the file https://dl.dropbox.com/u/54057365/All/Ireland.shp

I read the file into matlab using the code:

S = shaperead('Ireland.shp')

My question is how can I view the map?

I would appreciate it if anybody had the time to show me.

Also, is it possible to overlay GPS data on a file of this type?

Thank you

[alessio grechi]

ciao. Sei riuscito a far visualizzare la mappa in MatLab?

Answer 1

[José-Luis]

 doc mapshow

It can be as simple as:

 S = shaperead(filename);
 mapshow(S);

As long as you have latitude and longitude, you can plot pretty much anything

 doc plotm

[John]

Hello,

Thank you very much for your reply, I was able to display the map.

This is a screenshot

https://dl.dropbox.com/u/54057365/All/map.jpg

Could I ask you one further question?

As an example, I would like to plot a point for Dublin (the capital city).

This is the code I am using.

S = shaperead('ireland.shp');
 mapshow(S);
hold on
h = plotm(53.34419, -6.26751)

However, I getting an error:

Error using gcm Not a map axis

Thank you for your time

J

[José-Luis]

The short answer:

Use plot instead of plotm

The longer answer:

plotm is complaining that the current axes are not map axes. Map axes are better since they can handle projections and will not distort your data as vanilla axes will do. So, if you want to be thorough, first create an axesm object and plot your shapefile and point on it.

 doc axesm

[John]

Thank you for your help. Happy Christmas

[José-Luis]

My pleasure.

[John]

Hello,

When I use the plot function the point does not appear to be displayed on the map. I can't see it.

Also, I tried the other method, I displayed the map and typed "axesmui" but it says "not a map axis".

Can I ask the question, is the map I have suitable for overlaying latitude and longitude data on it. The axes scales don't seem to be in lat long format. Are they?

https://dl.dropbox.com/u/54057365/All/map.jpg

Would you know where I could source a suitable map?

What I am trying to do is overlay GPS data from a car on map and reproduce something like this:

I appreciate your help.

Thanks

J

[José-Luis]

If you are plotting a point, are you sure your Marker is large enough so you can see it, try a large size first

 plot(x,y,'LineStyle','none','Marker','o','MarkerSize',20);

The map you are linking to does not appear to be in lat-long, it looks like UTM.

I don't know where you could find a suitable map, but google can help you. You could also look at worldmap() from Matlab.

Answer 2

[John]

Hi Jose,

Thank for your help with this. I managed to get it working in the end. I sourced a better map using your suggestion worldmap().

I have one further question if you don't mind.

I am getting this map using the code below.

ax = worldmap('ireland');
land = shaperead('landareas', 'UseGeoCoords', true);
geoshow(ax, land, 'FaceColor', [0.5 0.7 0.5])

How can I just limit the display to just display between Lat 51-55.5 and long 5-10.5. I just want to display Ireland.

Thank you

J

[José-Luis]

 ax = axesm('MapProjection','mercator','MapLatLimit',[50 55.5],...
    'MapLonLimit',[-10.5 -5],'Frame','on')

 land = shaperead('landareas', 'UseGeoCoords', true);
 geoshow(ax, land, 'FaceColor', [0.5 0.7 0.5])

Please read the documentation about axesm() if you want to tweak the display.

[John]

Thanks very much

[John]

Hi,

I got this to work very well. Thanks for your help.

Can I ask you is it possible to use the colourmap editor on maps? I tried to use it to display areas with varying amounts of data in a different colours but it all stays blue.

Would you have any suggestions?

Thank you

J

[José-Luis]

 doc plotm

[Harold Steven Buitrago Segura]

Maybe you could use the geolimit function

Answer 3

[Clelia Massarino]

Hello,

I am having problem displaying the Germany map. My final goal is to have one with the elevation or at least different colors to discern different altitudes. I used the same code of you but it starts running endlessly. Any suggestion?

[Alessandro Mura]

@Clelia Massarino sei riuscito a cambiare i diversi colori della mappa della Germania? se si ti posso chiedere per favore lo script?

ti ringrazio