USACE Hydrographic Surveys (eHydro) in OpenCPN

[Pandor]

I need some help in figuring out the best way to utilize the USACE Hydrographic Surveys for US East Coast Inlets available at https://www.arcgis.com/apps/opsdashb...617bf1b6d2f85d

The web interface includes ability to download both data and pdf plotsheets. I find the plotsheets are very informative, usually including survey depths, depth color codings and even recommended waypoints. But I have not had very much luck figuring out how to utilize all of this great information on a chartplotter (short of inputting the suggested waypoints.

Some (but not most) of the data downloads include .KMZ files which are readable on Google Earth. So I guess it would be possible to convert MTB tiles out of that data.

But I would think there must be an easier way to use some of the data in OpcenCPN or similar ECS. Does anyone have any suggestions on how to best make use of the data or where I could find more information?

[sv_pelagia]

I am working with similar data for some uncharted areas of BC.

OpenCPN doesn't take these data directly/easily. (If a gpx file is available, you could bring this in, but that might be very cluttered.)

I have been using QGIS to import these data (I import xyz files), and then to output various files (including depth contours though I am not so happy with the contours).

You could create Geotif files which can then be overlaid in OPENCPN as a transparent layer using Photolayer plugin. Indeed you could do this using the easily accessed "PDF Plotsheet" provided for each USACE survey.

(QGIS can create a geotiff of the cropped pdf, after you use its calibration function.)

[wsmurdoch]

You might want to look at https://bobicw.blogspot.com/p/how-to...tracks_28.html .

But... I don't use any of this. I print out pdf files of the bad spots, keep them in the cockpit, and follow the markers especially the drop buoys.

Bill
Irish-Eyes-to-the-Bahamas.Blogspot.com

[PJHoffnet]

While not an answer to your question, Aqua Map uses the surveys and display directly in the program.

[Pandor]

Thanks, all, for replies. I’ve tried Aqua Map sometime ago and don’t recall enjoying it that much. Although if it does display the survey data, that might be worth a relook.

Photolayer plug-in sounds promising. I think in the past I had tried the approach of a transparent overlay using the weather fax plugin. But it was very cumbersome because I think the pdf needed to be converted to a jpg and the resolution stepped down. The biggest issue was that the plot sheets aren’t oriented north up. So the jpg files also needed to be rotated.

I haven’t tried Photolayer. Has anyone had success with this approach?

[sv_pelagia]

Photolayer works great, but...

You have to first georeference (what I meant by "calibrate") the image file. To do this, you need to know the lat/long of several points on the image (I try to use 4 points closer to the 4 corners).

Once georeferenced, no issue with North up, etc.

QGIS (free, opensource software) georeference is easy, outputting a geotiff that Photolayer will use.

(I wish Android OpenCPN had Photolayer plugin, though I do have an Android solution: "Qfield" , which easily displays QGIS info.)