Introduction

Pre-post processing of numerical models can take quite some time. Therefore it can be tempting to reduce the time available for proper post-processing. However, properly visualizing your results is of vital importance to any analysis. To help your reader to understand the geographical location it can be interesting to plot your results on a georeferenced map with a so-called geo-image. A geo image is being used by other post-processors simply as a background of model results. The standard post-processing tools (e.g. Quickplot, Matlab or Muppet) support images in “*.jpg” or “*.png” format. With the 'Geo Image' toolbox we can make such a geo-image.

Usage of the toolbox

The 'Geo Image' toolbox allows to download satellite images, or other map types, on a self-chosen window. These images can be saved in “*.jpg” format. An image can be generate using the following steps:
  1. The image window is defined by clicking on “Draw Outline” in the Working Space and then selecting the window by mouse clicking
    1. Alternatively, the window can be defined by its coordinates (“Xmin”, “Xmax”, “Ymin”, “Ymax“)
  2. Zoom level determines the resolution of the image with increasing level from 4 to 23. By default, the 'auto' option is used. 
  3. Different types of images are available under 'Type' namely
    1. Aerial (satellite) image
    2. Road image
    3. Hybrid: combination between a and b

 

Figure: With the Geo Image toolbox an image of the area of interest can be made, which can be used as the underlying layer in the presentation of computational results. In this example, we made a geo image of Barnegat Bay, NJ


Applying the image within Matlab

After the image is generated it can be used as a background image in Matlab.  See the example below of how to do this:

 

% load your geoimage

filename = 'p:\1230691-sri-lanka\02_data\geo_image\overall'; % dont use an extension
[x,y,z,col] = georeference_image(filename);

 

% create the figure

figure; hold on;
plt1 = surf(x,y,z,squeeze(col));shading flat;
plt2 = scatter(Xpoint, Ypoints, [], Zpoints);