Design Point Validation

This report validates feature-space coverage of the selected design points relative to the statewide population. It does not determine the optimal number of SIPNET design points. The 1,000-site design evaluated here is selected from the 10,000-site candidate pool for demonstration.

Overview

Design points are the field locations where SIPNET is run; a Random Forest then downscales those outputs to every cropland field in the CADWR LandIQ Crop Map. 020_cluster_sites.R clusters the population per plant functional type and keeps one representative per cluster as a 10,000-site candidate pool, 021_subsample_design_points.R draws the design from that pool by farthest point sampling, and 022_validate_design_points.R writes the tables and figures below. Coverage matters because the Random Forest predicts reliably only within the range of conditions the design spans, so gaps in covariate coverage become extrapolation.

Clustering uses seed 42 (020_cluster_sites.R).

PFT allocation

Population and design counts and area share per PFT.

pft	n_pop	area_pop	pct_pop_n	pct_pop_area	n_design	pct_design
woody perennial crop	215647	1683351	56	48.3	483	48.3
annual crop	169587	1802267	44	51.7	517	51.7

Feature space coverage (MSSD, scaled)

Mean squared shortest distance from each population field to its nearest design point in scaled feature space. Lower is better coverage.

pft	n_pop	n_design	mssd
annual crop	169587	517	10.6549
woody perennial crop	215647	483	10.4718

Cluster balance (Gini of cluster sizes)

pft	n_clusters	min_size	median_size	max_size	gini
annual crop	5171	1	25	335	0.436
woody perennial crop	4829	1	32	387	0.460

Anchor recovery

n_anchors	in_design	missing
27	27	0

Monitoring layer coverage

Share of the population and of the design carrying each management and phenology feature.

feature	pop_n	pop_pct	design_n	design_pct
tillage_rank	289392	75.1	766	76.6
tillage_freq	289780	75.2	773	77.3
leafon_doy	385234	100.0	1000	100.0
leafoff_doy	385234	100.0	1000	100.0
leafon_doy_sd	385234	100.0	1000	100.0
leafoff_doy_sd	385234	100.0	1000	100.0
irr_canopy	346937	90.1	709	70.9
irr_flood	26872	7.0	188	18.8

Climate region coverage

climregion_id	n_pop	pct_pop	n_design	pct_design
1	20607	5.3	59	5.9
2	15033	3.9	124	12.4
3	136802	35.5	263	26.3
4	3536	0.9	22	2.2
5	10454	2.7	33	3.3
6	4626	1.2	20	2.0
7	50600	13.1	125	12.5
8	29636	7.7	83	8.3
9	6351	1.6	33	3.3
10	1692	0.4	13	1.3
11	105897	27.5	225	22.5

Figures

Variable importance (eta-squared)

Design points on California cropland

Nearest-neighbor distances

CDF overlay (annual crop)

PCA scatter (annual crop)

Sorted cluster sizes (annual crop)

CDF overlay (woody perennial crop)

PCA scatter (woody perennial crop)

Sorted cluster sizes (woody perennial crop)