SMS:Electronic Charts: Difference between revisions

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Since surveys can be expensive to obtain, and DEMs may not be applicable,  another option available for the hydraulic modeler is the use of  topographic/bathymetric charts or historic nautical charts. If these types of  maps can be digitized into an electronic format, they can be read into SMS and  displayed on the screen. The goal is to create a scattered data set from this  electronic chart. The steps to do this include:
#redirect [[SMS:Scatter Module#Data Sources]]
 
# Scan the paper map and save it as an image (*.tif, *.jpg, ...).
# Register the image  (you may want to mark the map with your register points prior to scanning  it).
# Select the Create Vertex tool  in the Data  Module.
# Digitize (click on the image on the screen) to create a vertex on a contour  line in the image.
# In the z edit box of the edit window set the z value to the contour value of  the line.
# Digitize along the specified contour value (the spacing of points along the  contour lines should be approximately the same distance as the spacing between  adjacent contours).
# Repeat steps 4–6 for each contour line.  Spot elevations can be entered by  setting the z value to the value of the spot elevation and then creating a  vertex at that location.
# Triangulate the  vertices once you are done.
 
 
This method becomes tedious for larger areas, but is ideally suited for  smaller areas where there are not too many contours to be digitized.
 
 
[[SMS:Scatter Module|Return to Scatter Module]]

Latest revision as of 20:50, 17 December 2013