Map Editor truncating map extension on ocean side?

[Pablo Faúndez]

Hello,

I downloaded elevation data from GWA map warehouse for a coastal site, using Map Editor 12.4.

It seems that the program is truncating the map extension to areas of existing contour lines on the continent. The coast I am dealing with is the Pacific Ocean so I have 1000s of km without contours in that direction. This truncation effectively reduces the distance to the map border recommended for modeling with WaSP (modelling height x 100).

Should I worry or try to fix this manually (eg. creating a small contour line say 10km off the coast)?

Or am I skipping some step when downlading elevation data?

Thanks very much!

[Morten]

The map editor limits the map domain as you describe, because it does not know for sure how far the water surfaces extends into the unknown. However, you can select Edit> Adjust map domain size in the main menu of the Map Editor main window (not the Map display window) and extend the map domain size manually. 

As an alternative, you can extend the map from inside WAsP. For this you right-click the vector map in the object hierarchy and select Change Extend of map from the popup menu. 

The domain editor of WAsP Engineering program generates a grid map based on your vector map. For coastal or offshore sites, we sometimes need to extend that map in the offshore direction. For this you first zoom out the displayed  vector map and then you can select a grid map with more extend in the offshore direction. The zoom button in the WAsP Engineering domain editor window is the second one next to the line with the name of the vector map, see below.     

 

[Morten]

I was testing my above method and need to correct myself. It seems like the map editor does not save information about the adjusted map size to file. so I guess thise merely was intended as a way to enlarge the 'canvas' while 'painting' roughness-change lines and elevation contours manually. 

In most cases you can use the methods inside WAsP and WAsP Engineering as described in my post above, but not for the Prepare data for WAT tool inside WAsP Engineering. The trouble is that this tool will ask you for a WAsP vector map file and then do some WAsP calculations for mean wind climates. As you can imagine, this can fail if the map does not include an offshore wind farm. A work-around method is to

• open the map in the map editor
• adjust the map size to include the wind farm
• create a dummy roughness line as a polygon surrounding the offshore wind farm
• specify water surface roughness both inside and outside that polygon.

Load the map with the amended map into the Prepare data for WAT tool and its WAsP calculations should work without problems.    

Edited June 6 by Morten

[Pablo Faúndez]

Thanks very much Morten, the dummy roughness line works perfectly.