Elevation data returned by elevation_bygrid() has changed with 0.19.0

[gecrooks]

What happened?

The elevation data returned by elevation_bygrid() has been stable since at least version 0.15, but it changed with version 0.19.0. The new data seems to be incorrect, with anomalies visible at high resolution.

What did you expect to happen?

No response

Minimal Complete Verifiable Example

import numpy as np
import py3dep

# 0.001° (~110 m) box near Half Dome
west, east = -119.57, -119.569
south, north = 37.72, 37.721

longs = np.linspace(west, east, 3)
lats = np.linspace(south, north, 3)

da = py3dep.elevation_bygrid(
    tuple(longs),
    tuple(lats),
    crs="EPSG:4326",
    resolution=10,
)

print(f"py3dep {py3dep.__version__} → shape {da.shape}, dtype {da.dtype}")
print(da.to_numpy())

MVCE confirmation

• Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue.
• Complete example — the example is self-contained, including all data and the text of any traceback.
• New issue — a search of GitHub Issues suggests this is not a duplicate.

Relevant log output

py3dep 0.18.0 → shape (3, 3), dtype float64
[[2094.10516314 2075.2293798  2057.74301692]
 [2095.6498818  2068.41743071 2043.76287735]
 [2114.013507   2085.72606709 2055.79326402]]

py3dep 0.19.0 → shape (3, 3), dtype float64
[[2094.55753355 2073.46181724 2057.98878317]
 [2094.03386831 2069.5693885  2042.98432077]
 [2113.23678663 2083.09267672 2060.18754251]]

Anything else we need to know?

No response

Environment

Details

[cheginit]

Thanks for reporting this discrepancy. This function hasn't changed between the two versions. This function uses xarray to interpolate the data. Can you provide the xarray and scipy versions when you install 0.18 and 0.19?

[gecrooks]

It's scipy 1.16.2 and xarray 2025.10.1 in both cases.

[cheginit]

I see, thanks. Ok, I'll look into it.