bbest
commented
7 years ago Hi @lkilcher,
Here's a little update on the depth-varying buffer, since this is the most novel targeted product related to the cable analysis. Initially, I did this for the small experimental area of Morro Bay, CA where a floating offshore wind farm is currently proposed amongst California Activities by BOEM.
I applied a depth-varying buffer to the offshore cables, 2 * depth for "minimum" and 3 * depth for "recommended" separation zones for routing new cables, by first intersecting depth with cables, then iterating over each depth to apply the appropriate buffers before finally dissolving all buffers. In order to apply the buffer, I needed to project from geographic coordinates to a projection that minimizes area distortion, so chose Albers Equal Area and applied the "one-sixth rule" based on the extent of the cable features to minimize distortion.
You can see the interactive map in the report's section 2.3.3 Depth-Varying Buffer: Morro Bay example and R code by clicking on the Code button:
Next steps. The above R code works well for this small area, but will not scale well to the national level. I'll implement the intersection, buffering and dissolve operations in a PostGIS spatial database, which has the advantage of much more efficient spatial indexing and operations.
Perform spatial analysis. Product layer(s) will be generated via fully reproducible scripts, either in the R statistical language (using raster and sf packages, possibly with PostGIS) or Python (with open-source GeoPandas package). Scripts will be posted online to a publicly available Github repository and versioned with a digital object identifier (DOI) for citing in the report.