intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 
 

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

 

 

Message Boards

RE: Raster to .xyz file (ArcGIS)

LC
Luca Castrucci, modified 3 Years ago.

Raster to .xyz file (ArcGIS)

Youngling Posts: 14 Join Date: 6/17/16 Recent Posts
These days I am having problems to convert my bathymetry from a raster to a .xyz file, to use with RGFGRID/QUICKIN. I have tried to convert the raster to an ASCII file using "ArcGIS - Conversation Tools - From Raster to ASCII', but since the points elevations are grouped together it did not work. Moreover, the ASCII file do not have the x and y values. I have looked for other options, and I found " 3D Analysis Tools - Conversion - From Feature Class - Feature Class Z to ASCII" which gives outputs in the format x1,y1,z1 etc..., but unfortunately I don't have the license to use this tool. Another thing I have noticed is that no other file except raster can be converted to ASCII file. This makes me think that the only way to create an .xyz file is to convert a raster with x,y and z values to an ASCII file, arrange the data in the correct format (three columns) and then rename it .xyz.
How do you usually create .xyz file from a bathymetry raster?
DK
Dmitry Kushnir, modified 3 Years ago.

RE: Raster to .xyz file (ArcGIS)

Padawan Posts: 85 Join Date: 11/9/12 Recent Posts
Hi Luca,

How about creating isolines from the raster? You can then convert polylines to points, and export X, Y and Z values to the ASCII-file.
I usually use that option for .xyz files.
If you need more information, let me know.

Regards,

Dmitry
LC
Luca Castrucci, modified 3 Years ago.

RE: Raster to .xyz file (ArcGIS)

Youngling Posts: 14 Join Date: 6/17/16 Recent Posts
Dimitry thank you for the hint. But I don't think I understood it completely. So what you do is:
1) Using "Spatial Analysis - Contour" you create isolines, which value do you use for contour interval?
2) How do you convert the isolines to points? Do you use the tool "Data Management Tools - Sampling - Generate Points Along Lines"?
3) After having the points (X and Y), do you use the tool "Spatial Analysis Tools - Extract Values to Points" to get the elevation (Z)?
4) As far as I know, only rasters seem to be exportable in ASCII-file, but I am newer to ArcGIS as well, so I am probably wrong. Can you go a little more into the details of your procedure?

Regards,

Luca
DK
Dmitry Kushnir, modified 3 Years ago.

RE: Raster to .xyz file (ArcGIS)

Padawan Posts: 85 Join Date: 11/9/12 Recent Posts
Hi Luca,

1) I use Spatial Analyst >Surface> Isolines to create isolines from raster. For contour interval an arbitrary value can be chosen, based on the model refinement.
2) To convert isolines to points: Data Management Tools> Features > Feature Vertices To Points.
3) I actually don't use Spatial Analysis Tools > Extract Values to Points, as Z-values should have already been present in the attributive table of the points-layer. Instead, you will have to add x- and y- coordinates to the table. It can be done through Data Management Tools>Feature>Add XY Coordinates.
4) Next, you'll have to export resulting attributive table to the appropriate file format to catch it in Quickin.
For instance, you might consider using Conversion Tools>Table to dBase. dBase format is readable by many other programs, e.g. Excel, from where you can export to the ACSII .txt-file. Or directly export table to the .xls-file (Conversion Tools> Table to Excel).

There is also more straightforward way for exporting raster to ASCII (skipping the creation of isolines): Conversion Tools>Raster to Point. As a result, we get a points layer in a shape-file format with Z-values in the attributive table. Then we just have to complete steps 3) and 4).

Hope this helps.

Regards,

Dmitry
LC
Luca Castrucci, modified 3 Years ago.

RE: Raster to .xyz file (ArcGIS)

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

Thanks for your guide lines. I have worked on it today but I got a problem between step 3 and 4. When I tried to add X and Y coordinates, ArcGIS gave me the error: "Out of memory. The dataset is too large to complete this operation. Returning to previous state". Maybe I have more points than ArcGIS can handle. The strange thing is that I have this problem only when I use Conversion Tool > Raster to Points, with isolines it works great. Do you have the same problem?
Which methods between the two do you use the most? I believe that the Raster to point is the better one since all points are selected, thus it makes the bathymetry on QUICKIN more precise.

Best

Luca
YJ
Yoan Jericko, modified 16 Days ago.

RE: Raster to .xyz file (ArcGIS)

Youngling Posts: 16 Join Date: 9/26/19 Recent Posts
Luca Castrucci:

These days I am having problems to convert my bathymetry from a raster to a .xyz file, to use with RGFGRID/QUICKIN. I have tried to convert the raster to an ASCII file using "ArcGIS - Conversation Tools - From Raster to ASCII', but since the points elevations are grouped together it did not work. Moreover, the ASCII file do not have the x and y values. I have looked for other options, and I found " 3D Analysis Tools - Conversion - From Feature Class - Feature Class Z to ASCII" which gives outputs in the format x1,y1,z1 etc..., but unfortunately I don't have the license to use this tool. Another thing I have noticed is that no other file except raster can be converted to ASCII file. This makes me think that the only way to create an .xyz file is to convert a raster with x,y and z values to an ASCII file, arrange the data in the correct format (three columns) and then rename it .xyz my ip birthday wishes  tneb
How do you usually create .xyz file from a bathymetry raster?
If you need more information, let me know.