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Hi

 

I have been preparing floodplain maps in vertical mapper and mapinfo but am unable to get the presentation I require.

 

I usually start by importing the *.asc file from tuflow_to_gis.exe into vertical mapper and once I have a grid I have tried the following:

1. reclassify the grid into separate classes based on inundation depth range - however this method produces maps that are not crisply defined at the edges (they are hazy)

2. contour the grid into various colour regions - however this produces a map that does not show the individual grid squares because the contours smooth it out into triangles on the boundaries between colours.

3. reclassify the grid first, and then contour the reclassified grid into regions.  This produces a nice crisp map with the inundation depth range colour visible in each grid square, however each class is separated by a black line that I am not able to remove in Mapinfo successfully.

 

So what I am after is a nice crisp mapinfo layer of the flood inundation depth ranges that is not separated by black lines.  An example of what I am after is attached.

 

Can someone please let me know where I am going wrong?

 

post-32239-0-55174000-1425271921_thumb.j

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Using your third method you should be able to remove the black border. Convert the grid into regions, double click the region layer in the Mapinfo layer control and change the style as you would with any polygon.

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Thanks but this is where things get tricky.  Once the grid is converted into regions, all of the colours appear as the native presentation of the layer.  So as soon as I click on layer control and remove the black lines, the entire layer becomes white and invisible.  I can recolour this layer but then I end up with a single colour for all depths and not the 7-8 colours that are required for each inundation range.  The only way around this issue is to create a thematic map for each inundation range.  But the image I supplied in my first post has all the colour ranges shown without needing a thematic map linked to a workspace.

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There may be another way of doing this.  The asc_to_asc utility allows you to classify a grid based on a .csv file of classes.  See here for instructions on using this utility:

http://wiki.tuflow.com/index.php?title=ASC_to_ASC#Classify

 

If you are using Vertical Mapper you can use the -grc option to create a classified grid (rather than a numeric grid).

 

Finally, as of the 2013 version of TUFLOW you can output the results to gridded format directly from TUFLOW, bypassing the need to use the TUFLOW_to_GIS utility.  See the release notes for more information on this.

 

Cheers

Phil

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