perimeter/site/index.html at main · ghzhost/perimeter · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Perimeter | Coverage measures for California wildfire datasets</title>
<meta name="description" content="Coverage and completeness counts over California's public wildfire datasets. Unofficial.">
<style>:root {
  color-scheme: light;
  --surface: #fcfcfb;
  --surface-raised: #ffffff;
  --rule: #e2e0d9;
  --rule-strong: #c9c6bc;
  --ink: #14140f;
  --ink-2: #52514e;
  --ink-3: #6f6d66;
  --accent: #1c5cab;
  --present: #2a78d6;
  --unknown: #eb6834;
  --absent: #189a6b;
  --quote-bg: #f5f4f0;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --surface: #1a1a19;
    --surface-raised: #232321;
    --rule: #383835;
    --rule-strong: #4f4e4a;
    --ink: #f7f6f2;
    --ink-2: #c3c2b7;
    --ink-3: #9d9b92;
    --accent: #86b6ef;
    --present: #3987e5;
    --unknown: #d95926;
    --absent: #199e70;
    --quote-bg: #232321;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --surface: #1a1a19;
  --surface-raised: #232321;
  --rule: #383835;
  --rule-strong: #4f4e4a;
  --ink: #f7f6f2;
  --ink-2: #c3c2b7;
  --ink-3: #9d9b92;
  --accent: #86b6ef;
  --present: #3987e5;
  --unknown: #d95926;
  --absent: #199e70;
  --quote-bg: #232321;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--surface);
  color: var(--ink);
  font: 400 17px/1.62 ui-serif, "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
}
.wrap { max-width: 62rem; margin: 0 auto; padding: 0 1.5rem 5rem; }
a { color: var(--accent); }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap;
}
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 10;
  background: var(--surface-raised); color: var(--accent);
  padding: .6rem 1rem; border: 1px solid var(--rule-strong);
}
.skip-link:focus { left: .5rem; top: .5rem; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
h1, h2, h3, .tile-value, .num, thead th, .eyebrow, .legend, .badge, nav {
  font-family: ui-sans-serif, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
h1 { font-size: clamp(1.9rem, 1.3rem + 2.4vw, 2.9rem); line-height: 1.14; letter-spacing: -0.02em; margin: 0 0 .6rem; }
h2 { font-size: 1.4rem; letter-spacing: -0.01em; margin: 3.4rem 0 .4rem; padding-top: 1.6rem; border-top: 1px solid var(--rule); }
h3 { font-size: 1.02rem; letter-spacing: .01em; margin: 2rem 0 .5rem; color: var(--ink-2); }
p { margin: 0 0 1rem; max-width: 46rem; }
.eyebrow { font-size: .74rem; letter-spacing: .13em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 .8rem; }
.standfirst { font-size: 1.16rem; color: var(--ink-2); max-width: 44rem; }
.lede { max-width: 44rem; }

nav { border-bottom: 1px solid var(--rule); margin-bottom: 2.6rem; }
nav .wrap { display: flex; flex-wrap: wrap; gap: 1.4rem; align-items: baseline; padding-top: 1rem; padding-bottom: 1rem; }
nav a { font-size: .88rem; text-decoration: none; }
nav a:hover { text-decoration: underline; }
nav .mark { font-weight: 700; letter-spacing: .04em; text-transform: uppercase; font-size: .8rem; color: var(--ink); }

header.page { padding: 2.2rem 0 0; }
.badge {
  display: inline-block; font-size: .72rem; letter-spacing: .07em; text-transform: uppercase;
  border: 1px solid var(--rule-strong); color: var(--ink-3);
  border-radius: 999px; padding: .22rem .7rem; margin-bottom: 1.4rem;
}

.tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr)); gap: 1px; background: var(--rule); border: 1px solid var(--rule); margin: 2.2rem 0 1rem; padding: 0; list-style: none; }
.tile { background: var(--surface-raised); padding: 1.1rem 1.2rem 1.2rem; }
.tile-value { font-size: 1.72rem; font-weight: 600; letter-spacing: -0.02em; line-height: 1.1; }
.tile-label { font-size: .82rem; color: var(--ink-2); margin-top: .35rem; line-height: 1.4; }

.scroll { overflow-x: auto; border: 1px solid var(--rule); margin: 1.2rem 0; background: var(--surface-raised); }
.scroll.tall { max-height: 30rem; overflow-y: auto; }
table { border-collapse: collapse; width: 100%; font-size: .87rem; }
thead th {
  position: sticky; top: 0; background: var(--surface-raised);
  text-align: left; font-size: .72rem; letter-spacing: .06em; text-transform: uppercase;
  color: var(--ink-3); font-weight: 600; padding: .7rem .8rem; border-bottom: 1px solid var(--rule-strong);
  white-space: nowrap;
}
tbody td, tbody th { padding: .55rem .8rem; border-bottom: 1px solid var(--rule); vertical-align: middle; }
tbody th { font: inherit; font-weight: 400; text-align: left; }
tbody tr:last-child td, tbody tr:last-child th { border-bottom: 0; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }
td.field { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: .78rem; color: var(--ink-3); }
td.name { min-width: 12rem; }
.absent-note { color: var(--ink-3); font-style: italic; }

.legend { display: flex; flex-wrap: wrap; gap: 1.2rem; font-size: .8rem; color: var(--ink-2); margin: 1.4rem 0 .2rem; padding: 0; list-style: none; }
.legend li { display: flex; align-items: center; gap: .45rem; }
.swatch { width: .8rem; height: .8rem; border-radius: 2px; flex: none; }
.sw-present { background: var(--present); }
.sw-unknown { background: var(--unknown); }
.sw-absent { background: var(--absent); }

.bar { display: flex; gap: 2px; height: 11px; min-width: 8rem; width: 100%; }
.bar i { display: block; height: 100%; }
.bar i:first-child { border-radius: 3px 0 0 3px; }
.bar i:last-child { border-radius: 0 3px 3px 0; }
.bar i:only-child { border-radius: 3px; }
.b-present { background: var(--present); }
.b-unknown { background: var(--unknown); }
.b-absent { background: var(--absent); }
td.barcell { width: 34%; min-width: 9rem; }

blockquote {
  margin: 1rem 0 1.4rem; padding: 1rem 1.2rem; background: var(--quote-bg);
  border-left: 3px solid var(--rule-strong); font-size: .95rem; color: var(--ink-2);
}
blockquote p { margin: 0; max-width: none; }
.measured { font-size: .9rem; color: var(--ink-2); max-width: 44rem; }
.measured strong { color: var(--ink); font-weight: 600; }

dl.meta { display: grid; grid-template-columns: max-content 1fr; gap: .45rem 1.4rem; font-size: .87rem; margin: 1.2rem 0; }
dl.meta dt { color: var(--ink-3); }
dl.meta dd { margin: 0; word-break: break-word; }

footer.page { border-top: 1px solid var(--rule); margin-top: 4rem; padding-top: 1.6rem; font-size: .84rem; color: var(--ink-3); }
footer.page p { max-width: 44rem; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr)); gap: 1.4rem; margin: 2rem 0; }
.card { border: 1px solid var(--rule); background: var(--surface-raised); padding: 1.3rem 1.4rem 1.5rem; }
.card h3 { margin-top: 0; color: var(--ink); font-size: 1.08rem; }
.card p { font-size: .9rem; color: var(--ink-2); margin-bottom: .9rem; }
</style>
</head>
<body>
<a class="skip-link" href="#content">Skip to the measurement</a>
<nav aria-label="Pages"><div class="wrap"><span class="mark">Perimeter</span><a href="index.html" aria-current="page">Overview</a><a href="perimeters.html">Fire perimeters</a><a href="dins.html">Damage inspections</a></div></nav>
<div class="wrap">
<main id="content">


<header class="page">
<p class="eyebrow">Coverage measurement</p>
<h1>Perimeter</h1>
<p class="standfirst">Two coverage measurements over California's public wildfire
datasets, published as counts. CAL FIRE and FRAP document the limits of these datasets in
their own metadata. This project counts those limits, per year and per incident, so the
people building on the data can reason about them.</p>
</header>

<p class="lede">Both datasets carry careful descriptions of what they do and do not
contain. What is not published alongside them is the arithmetic: how many records per year, how
many carry a federal identifier, how many cells in each field hold a value, how many hold
a code meaning the value could not be determined, and how many hold nothing at all. Those
are the numbers here. Nothing on these pages models fire risk, tracks an incident, or
estimates a loss.</p>

<h2>The two measurements</h2>
<div class="card-grid">
<div class="card">
<h3>Historical fire perimeter completeness</h3>
<p>23,334 perimeter records, counted per fire year, with IRWIN
identifier coverage inside each year, surviving records measured against the published
collection acreages, and counts of records sharing an identifier.</p>
<p><a href="perimeters.html">Read the measurement</a></p>
</div>
<div class="card">
<h3>Damage inspection coverage</h3>
<p>132,522 structure records across 451 incidents, with
per-field and per-incident completeness, and the difference between a structure that could
not be reached and a structure inspected and found undamaged kept visible throughout.</p>
<p><a href="dins.html">Read the measurement</a></p>
</div>
</div>

<h2>How absence is handled</h2>
<p>Every measured cell is counted in one of three states, and the three are never
collapsed into each other:</p>
<div class="scroll"><table>
<caption class="visually-hidden">The three states every measured cell is counted in</caption>
<thead><tr>
<th scope="col">State</th><th scope="col">What it means</th>
</tr></thead><tbody>
<tr><th scope="row" class="name">Recorded value</th><td>A value the agency wrote down, including a recorded zero and including findings of absence such as No Damage or No Eaves.</td></tr><tr><th scope="row" class="name">Recorded as unknown</th><td>A published code or marker meaning the value could not be determined. Somebody recorded that determination failed.</td></tr><tr><th scope="row" class="name">Empty cell</th><td>Nothing was written in the cell. For DINS, CAL FIRE states that attributes with null values could not be determined.</td></tr>
</tbody></table></div>
<p>A null is not a zero. A structure not inspected is not a structure without damage. A
field a dataset never collected is not a field full of zeroes. Where a share would have no
denominator, these pages print words saying so rather than a number. Where a value that
reads like a missing-data marker turns up in a field this project has not reviewed for
that marker, the build stops rather than guessing what it meant.</p>

<h2>Which judgment calls rest on what</h2>
<p>Deciding that a cell holds a marker rather than a value is a judgment, and the two
measurement pages label every field with the basis its markers rest on. Twelve of the
twenty-seven fields that declare any marker or finding are <strong>published</strong>:
the value is a code in the layer's own coded-value domain, or a sentence in the
publisher's documentation, and it can be re-read at the endpoints listed under Sources
below. The other fifteen are <strong>inferred</strong>: the field is free text, or the
value is one the published domain does not carry, and this project read it off the
acquired file. Both sets are counted the same way and neither is a defect in either
dataset; both publishers document the domains they constrain and say which fields are
free text. The difference is in how much weight a reader should put on the call, so the
pages print it rather than leaving it to be assumed. Every entry, with its evidence, the
URL it can be checked against, its effect on the published figures and a confidence, is
in <code>docs/MARKERS.md</code>.</p>

<h2>Sources</h2>
<p>Both datasets are published by the California Department of Forestry and Fire
Protection under a Creative Commons Attribution licence, and both were read from the
GeoServices endpoint listed among the dataset's own published resources. Geometry was not
requested, because no measurement here needs it. Full detail, including byte counts and
file hashes, is in <code>PROVENANCE.md</code> and repeated on each page.</p>
<dl class="meta"><dt>Dataset</dt><dd>California Historical Fire Perimeters</dd><dt>Publisher</dt><dd>California Department of Forestry and Fire Protection, Fire and Resource Assessment Program</dd><dt>Landing page</dt><dd><a href="https://data.cnra.ca.gov/dataset/california-historical-fire-perimeters">https://data.cnra.ca.gov/dataset/california-historical-fire-perimeters</a></dd><dt>Layer read</dt><dd>California Fire Perimeters (all)</dd><dt>Endpoint</dt><dd>https://services1.arcgis.com/jUJYIo9tSA7EHvfZ/arcgis/rest/services/California_Historic_Fire_Perimeters/FeatureServer/0/query</dd><dt>Licence</dt><dd>Creative Commons Attribution</dd><dt>Version</dt><dd>firep25_1</dd><dt>Retrieved</dt><dd>2026-08-07</dd><dt>Acquired</dt><dd>23,334 records, 7,964,688 bytes</dd><dt>SHA-256</dt><dd>9be7bcb9c08f6813ba13263eabebc96256f0ea8fb0e809ad8a4171046466a16a</dd></dl>
<dl class="meta"><dt>Dataset</dt><dd>CAL FIRE Damage Inspection (DINS) Data</dd><dt>Publisher</dt><dd>California Department of Forestry and Fire Protection</dd><dt>Landing page</dt><dd><a href="https://data.ca.gov/dataset/cal-fire-damage-inspection-dins-data">https://data.ca.gov/dataset/cal-fire-damage-inspection-dins-data</a></dd><dt>Layer read</dt><dd>POSTFIRE</dd><dt>Endpoint</dt><dd>https://services1.arcgis.com/jUJYIo9tSA7EHvfZ/arcgis/rest/services/POSTFIRE_MASTER_DATA_SHARE/FeatureServer/0/query</dd><dt>Licence</dt><dd>Creative Commons Attribution</dd><dt>Version</dt><dd>POSTFIRE_MASTER_DATA_SHARE</dd><dt>Retrieved</dt><dd>2026-08-07</dd><dt>Acquired</dt><dd>132,522 records, 163,728,068 bytes</dd><dt>SHA-256</dt><dd>7683850bec00c201ad05ae55ab3c70baf53acd298a1da2fe8fd3c5432a624761</dd></dl>

</main>
<footer class="page">
<p>Unofficial. Not affiliated with or endorsed by CAL FIRE, FRAP, or any California state agency.</p>
<p>Source data is published by the California Department of Forestry and Fire Protection
under a Creative Commons Attribution licence and is reproduced here only as counts.
This project holds no view on how any agency collects or manages its data. It counts what
the published files contain, in the terms the publishers use to describe them.</p>
</footer>
</div>
</body>
</html>