Compute a grid of flow directions across a specified venue using a locally-fitted conic discharge potential model.

A venue is an instance of a political division, administrative region, or user-defined domain, as enumerated and detailed in venues.py. The defined venues currently include:

• City
• Township
• County
• Watershed
• Subregion
• Neighborhood
• Frame

The static water level data used in the analysis comes from the Minnesota County Well Index (CWI).

• County Well Index

  • water_well_information.gdb
  • The Minnesota Geological Survey
  • <https://www.mngs.umn.edu/cwi.html>

Geographic information is extracted from four other databases.

• City, Township, and Unorganized Territory in Minnesota

  • bdry_mn_city_township_unorg.gdb
  • The Minnesota Geospatial Commons
  • <https://gisdata.mn.gov/dataset/bdry-mn-city-township-unorg>

• County Boundaries, Minnesota

  • bdry_counties_in_minnesota.gdb
  • The Minnesota Geospatial Commons
  • <https://gisdata.mn.gov/dataset/bdry-counties-in-minnesota>

• Boundaries of Minnesota

  • bdry_state.gdb
  • The Minnesota Geospatial Commons
  • <https://gisdata.mn.gov/dataset/bdry-state>

• National Hydrology Products: Watershed Boundary Dataset (WBD)

  • WBD_National_GDB.gdb
  • US Geological Survey
  • <https://www.usgs.gov/core-science-systems/ngp/national-hydrography>

The Akeyaa analysis is carried out at target locations within a selected venue. The target locations are selected as the nodes of a square grid covering the venue.

The square grid of target locations is anchored at the centroid of the venue, and the grid lines are separated by spacing. If a target location is not inside of the venue it is discarded.

For each remaining target location, all wells that satisfy the following criteria are identified:

• the well is within a horizontal distance of radius of the target location,
• the well is completed in one or more of the aquifers,
• the water level measurement date is on or after firstyear, and
• the water level measurement date is on or before lastyear.

If a target location has fewer than required identified (neighboring) wells it is discarded.

The Akeyaa analysis is carried out at each of the remaining target locations using the method for fitting the conic potential model.

Data from outside of the venue may also be used in the computations. However, only data from the Minnesota CWI are considered.