intro story D-Flow FM

 

D-Flow Flexible Mesh

D-Flow Flexible Mesh (D-Flow FM) is the new software engine for hydrodynamical simulations on unstructured grids in 1D-2D-3D. Together with the familiar curvilinear meshes from Delft3D 4, the unstructured grid can consist of triangles, pentagons (etc.) and 1D channel networks, all in one single mesh. It combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration, resulting in:

  • Easier 1D-2D-3D model coupling, intuitive setup of boundary conditions and meteorological forcings (amongst others).
  • More flexible 2D gridding in delta regions, river junctions, harbours, intertidal flats and more.
  • High performance by smart use of multicore architectures, and grid computing clusters.
An overview of the current developments can be found here.
 
The D-Flow FM - team would be delighted if you would participate in discussions on the generation of meshes, the specification of boundary conditions, the running of computations, and all kinds of other relevant topics. Feel free to share your smart questions and/or brilliant solutions! 

 

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We have launched a new website (still under construction so expect continuous improvements) and a new forum dedicated to Delft3D Flexible Mesh.
Please follow this link to the new forum: 
/web/delft3dfm/forum
Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.

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Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 

Message Boards

Land Boundaries Problem

LC
Luca Castrucci, modified 4 Years ago.

Land Boundaries Problem

Youngling Posts: 14 Join Date: 6/17/16 Recent Posts
I do have a raster figure of the area that I am interested. In order to get the land boundaries I am following this procedure:
1) Clip the part of the raster I am more interested to.
2) Convert the clip to a polyline
3) Convert the polyline from a Feature class to a shapefile.
4) Open the shapefile with Quickplot to get the land boundaries
The problem happens when I try to open the shapefile using Quickplot, which crashes. I believe that the problem is related to the high number of squares that the conversion between raster to polyline creates. Here I have attached two pictures, one related to the area I am analyzing (as a shapefile) and, the second one is the zoom 1:6000 of the shapefile. It is possible to see all this little squares which together forms the land, but I think they make Quickplot crashes. I have tried to open the shapefile with Matlab as well, and it didn't work. Using the function shaperead I got a matrix of 4746577x1, which takes an infinite amount of time to be plotted.
I was guessing if there is a way to extract only the contour part of the shapefile without the inside part?
How do you usually solve land boundaries problems like this one?
rgfgrid complex land boundary

Attachments:

Richard Measures, modified 4 Years ago.

RE: Land Boundaries Problem

Jedi Knight Posts: 178 Join Date: 3/23/11 Recent Posts
Hi Luca,

Are you using ArcGIS? If so you can use spatial analyst to reclassify your raster so it is binary (e.g. one for land, zero for water) before converting it to a polygon/polyline - that way it should group the raster cells which have the same value into one big polygon/polyline. There's probably lots of ways of doing this but I would use "Spatial Analyst Tools - Conditional - Con" to reclassify the raster into dry/wet areas.

Hope that helps. Cheers,

Richard
land boundary file arcgis raster
LC
Luca Castrucci, modified 4 Years ago.

RE: Land Boundaries Problem

Youngling Posts: 14 Join Date: 6/17/16 Recent Posts
Hi Richard,

Thanks for your advise, it was very helpful. I reclassified my raster but I have used different tools. What I have done was to use "Spatial Analysis - Multivariate- Iso Cluster Unsupervised Classification" to create different classes based on the elevations, and then using "Spatial Analysis - Reclass - Reclassify" I reduced the classes to two, land and water. In my case, I was lucky because my DEM was coming from a LIDAR which reported all water with an elevation value of 0.
So now, I have this raster reclassified with only two classes, and I have to convert it to polyline first, and then to a shapefile for quickplot. The problem is that the conversion from raster to polyline is taking a lot of time. My raster is pretty big (around 3Gemoticon, but I am not sure if it depends on the size since the polyline conversation should only be about the borders right?
Please let me know if you have the same problem when you process big rasters.

Best

Luca