How to create P2D file in EFDC Explorer

If you do not have the shape file of the area you are working on then you might have difficulty to create the polygon file that can be used to create the grid.

However, you can use the following tools to create the p2d file to use in EFDC Explorer.

The software / tools that are required for this process are as follows. All of the tools are free tools.

1)      Google earth

2)      KML CSV Converter

3)      EFDC Explorer (WEB / TRIAL / FULL)

4)      CORPSCON

Step 1:

First of all, let us understand what are the data required to create the data. We required an outline of the water body for which we want to create the mesh / grid. In this case, we need the outline / polygon for the Lake Okeechobee. The easiest way to get the outline points is via the Google Earth. In Google Earth we can create a folder and create new place mark along the shoreline of Lake Okeechobee as shown in Figure 6.

Snapshot of google earth

Snapshot of Google earth showing the placemark along the shoreline of Lake Okeechobee

Step 2:

The second step is to output the coordinates of the place marks in Google Earth to real coordinates. We can save all the placemarks on one folder and save the folder as kml file. The saved kml file can be used in a third party application named “KML CSV Converter” and export the csv file as shown in Figure 7. Step 2 is completed after exporting the csv file from the application. The exported coordinates will have the Geographical coordinate system. In EFDC we need to use the UTM coordinate system. So, in third step, the GCS data will be converted into UTM data.

kml to csv

A snapshot of KML CSV Converter showing the longitude and latitude of the place marks in Google Earth

Step 3: Conversion of GCS data to UTM data:

There are several ways the data in geographical coordinate system can be converted to UTM coordinate system. Users can use ArcGIS or CORPSCON software to convert the data from GCS to UTM. Corpscon software can be downloaded from http://www.agc.army.mil/corpscon/ .

corpscon

Snapshot of Corpscon Setup for the conversion from Geographic NAD (North American Datum) 1983 to UTM 1983

Alternatively you can use ArcGIS to change the geographic datum.

Step 4: Create the polygon file from the UTM coordinate data

In EFDC explorer, we need to provide the outline of the water body in the polygon (*.p2d) format. The steps 1-3 we performed to ultimately create a polygon file for the water body (Okeechobee in this case). The polygon file has 3 fields. The first field is X coordinate (longitude), second is y coordinate (latitude) and last is serial number which represents the data count. The first and the last points should be the same in order to ensure the polygon in closed. Figure 10 shows the format of the polygon file and it can be observed that the first and last points are the same. Looking at the data set we know that there are 22 points in the polygon.

p2d sample

Snapshot of the polygon data file to be used while creating the grid in EE.

Thus you can create the polygon file that you can use in EFDC Explorer.

Please write your comments if you have any other ideas.

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8 comments on “How to create P2D file in EFDC Explorer

  1. Really thank you very much indeed for your complete description!
    I want to make the curvilinear grid for my site study.Regarding the examples which are available on the site (Ohio River) I could make the centerline and outline p2d files for my site study, but I do not know how can I make the section file (section.dx). I will appreciate you if you help me. How can I make a new section file or change the contents of available files based on the my site data!

  2. I should mention that I know the conception of the section files. I need some helps to find a correct and quick way to make the section file!

  3. Mohammad, if you want to create curvilinear grids, then you can try Delft RGFgrid module and it is very easy to create curvilinear grids on that software. You can request for the trial version of the software also. I haven’t personally used the curvilinear option in EFDC Explorer. I will check and give you my feedback. Thanks for checking my blog.

  4. Hi
    Thank you very much indeed for your kind helps
    Could you pleas let me know how can I download the Delft RGFgrid module? I could not find any links for downloading!
    Regards

  5. Dear Kester

    Hello. I deeply appreciate you for kind helps and supports.
    I made curvilinear model for my site study using UTM system. Would you please let me know how can I made geo file for my study site. For example, there is an example of this file in west Lake.
    I want to open this file as background for better visualization.

    Regards
    Mohammad

  6. Hi Mohammad,
    I am sorry it took quite a while to get back to you. To create a georeference file you can go to EFDC Explorer main menu and then under the ToolBag menu, there is a option of Bitmap Geo referencing. When you click on that option, a window opens and you can import an image and then you can choose two points to georeference. There is a short tutorial on EFDC Explorer manual. Would you check that and let me know if the problem persists ? BTW I am not Kester. I am Janesh Devkota from Auburn University and I write this blog to share my experience with fellow EFDC users.

  7. hi, where can i find westlake outline .p2d it is not available in zip file of west lake example which is downloadable from the efdc explorer website. can you please give me a link to send it to me via email? thank you.

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