---
title: "Surface profiles, depth to water, and cross-sections"
description: "Derive depth surfaces and extract transect profiles and plot-ready cross-sections from modeled heads."
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Surface profiles, depth to water, and cross-sections}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r setup}
library(potentiomap)
data("synthetic_wells")
data("synthetic_transect")
p <- ps_make_points(synthetic_wells, "x", "y", "gw_elevation",
                    "well_id", "EPSG:26916")
head <- ps_interpolate(p, methods = "IDW", grid_res = 300)$IDW
land <- head * 0 + 185
line <- terra::vect(synthetic_transect, geom = "wkt", crs = "EPSG:26916")
```

```{r products}
depth <- ps_depth_to_water_surface(head, land, "potentiometric")
depth$summary
profile <- ps_surface_profile(line, list(head = head, land = land), n = 12)
head(profile$profile)
section <- ps_cross_section(line, head, land, step = 300,
                            vertical_exaggeration = 3)
section$summary
```

A confined potentiometric surface is not relabeled a water table. The
cross-section does not invent hydrostratigraphy or represent a 3-D flow model.