So I am trying to create a workbench that will take a 3D Polyline and drape the vertices based on the USGS 10m NED data. I would like for the data to be queried based on the 3D Polyline which will be projected into a UTM Zone based on US Survey Feet. The thought of using an HTTPCaller has been suggested, however I am not quite sure on the steps to take to ensure the query is accurate.
Has anyone achieved this?
Hi @jberneathy,
You will have to build you're request to meet the requirements of the servers you are accessing. Is there any documentation at USGS that you can use - or, if applicable, the general structure of the URLs you want to access? - this looks like a good place to start: https://nationalmap.gov/epqs/
For me the first place I would start would be learning how the requests work, sending manual HTTP requests and getting the response I'm expecting. Once I have that then I would look to automate the extraction of the required info from your Polylines and build it into the request. We have a number of tools on how you might go about doing this but it all depends on the structure of the request. The next part will involve getting the Data from the response into FME.
Have you looked at the MapzenAWSDEMDownloader - This is a custom transformer. It might save you some work. I'm not sure if it's the same data but it's a DEM and the resolution looks to go as high at 10 m per pixel. Something to think about anyway.