technical details

app.py

@@ -337,4 +337,46 @@ with col2:
 with col3: 
     st.altair_chart(rsr_chart, use_container_width=True)
 
+'''
+## Technical errata
+
+
+**Protected Areas** data are derived from the 
+
+> U.S. Geological Survey (USGS) Gap Analysis Project (GAP), 2022, Protected Areas Database of the United States (PAD-US) 3.0: U.S. Geological Survey data release, https://doi.org/10.5066/P9Q9LQ4B.
+
+Data is subset to the continental US (matching availability in MOBI data), and restricted to feature classes of "Fee" and "Easements",
+except for tribal boundaries which are taken from the "Proclamations."  See [ProtectedLands.net](https://www.protectedlands.net/pad-us-data-structure-attributes/)
+for a more detailed discussion of the data structure and classification involved in PAD.
+
+USGS PAD-v3 is distributed as an ESRI Geodatabase.  After subsetting the data and labelling according to the additional classification listed above based
+on manager type indicated in the data, core attributes are serialized into [PMTiles](https://docs.protomaps.com/pmtiles/) and [Geoparquet](https://geoparquet.org/)
+formats hosted on [source.coop](https://beta.source.coop/repositories/cboettig/pad-us-3/description/).  PMTiles allows for rapid rendering of vector objects
+at the appropriate zoom level in an interactive map from remote servers.  Geoparquet provides a high-performance serialization that can be efficiently queried directly from
+remote https addresses without download using software such as [duckdb](https://duckdb.org), widely available in python, R, and other languages.
+
+See our public Source.Coop repository [pad-us-3](https://beta.source.coop/repositories/cboettig/pad-us-3/description/) for more information on data processing
+and for direct access to the processed data layers.
+
+**Biodiversity Importance** data are derived from:
+
+> The Map of Biodiversity Importance, (2022), NatureServe. 
+
+The 2018 version of this data product can be found on Microsoft Planetary Computer, but the 2022 release is currently distributed through their [ESRI GeoHub](https://geohub-natureserve.opendata.arcgis.com/search?q=mobi).  
+The original data is provided in the geotiff format (ESRI  LayerFiles) at 990 meter resolution, and includes assets subset by various taxonomic groups for three indicators: for 2,216 imperiled species (species with global conservation status of G1, G2 or listed as threatened or endagered under the United States Ednagered Species Act).
+The indicators include species richness (the number of imperiled species occurring in a given pixel),
+range-size rarity (RSR, the sum of the inverse of the range sizes of each species occurring in a given pixel),
+and protection-weighted rRSR (RSR times the perecent of the range that is unprotected in GAP 1 & Gap 2).  
+See [geohub description](https://geohub-natureserve.opendata.arcgis.com/content/e5a6de94cc7b4d5b9204e2cc5d8b6e4e/about) for more details.
+Only data from all species for the species richness and RSR metrics is processed here (at the time of writing). 
+
+Our public Source.Coop repository [mobi](https://beta.source.coop/repositories/cboettig/mobi/) provides access
+to the geotiffs for species richness and RSR. 
+The repository also includes static tiles from zooms 1-10 that can be used as a static tile server in interactive maps.
+Technical details on processing are described in the repository.
+
+'''
+
+
+