Postholer - Hiking & GIS
@postholer
GIS, Interactive & Printed Trail Maps, Data Books, Trip Planners, Snow, Wildfires, Gear Lists, Open Source, GDAL Evangelist. , ,
As of this morning, Oregon is scorching the way for wildfires this season (so far). Utah is a very distant second: #wildfires #oregon
Here you go. I broke it down in several steps instead of a single pipeline:
The following creates a spatially indexed #flatgeobuf (FGB) of #USGSLandSat ARD #metadata by polygon. It accesses over 2.3 million rows (currently). 1982 to present. It is blazing fast and does not require an API or complex client stack. www.postholer.com/portfolio/no... #GIS
You can 'fix' it with another DEM. + get 1m DEM footprint as vector + clip 1m DEM with vector buffer -3 meters + stack a 10m DEM with the clipped 1m + clip stack'd to original footprint and save Untested GDAL attached:
Hurricane season is heating up. Interactive map: www.femafhz.com/map/30.07318... #hurricane #TD2
Stay up-to-date with the latest #surfaceSmoke conditions and air quality with this interactive map. Updates hourly: www.femafhz.com/map/39.74098... #wildfire #smoke #airquality
Tropical storm Elida and sea surface temps: www.femafhz.com/map/27.91676... Change the layer to sea surface anomaly to visualize how temps are compared to normal. Sea surface temps are actually below normal for a large swath near the California coast. #tropicalStorm #hurricane #elnino
Create a median composite raster from Sentinel-2 using only #GDAL This tutorial achieves the same result as #spatialthoughts Python tutorial: courses.spatialthoughts.com/python-remot... ...using only GDAL and Bash, without Python and it's dependencies. www.postholer.com/portfolio/no...
Animation, last 72 hours of smoke, hotspots and landcover that represents fire weather index. Updates every 4 hours. Lot's going on right now. www.postholer.com/trail-fires/...
Creating multi-layer images with GDAL CLI pipeline, using various nested raster/vector pipelines. Data: ETOPO_2022 1KM resolution bathymetry/elevation, NaturalEarth and trail vector data. #gis
Our trail fires page is ready for the upcoming fire season. We've added video that shows smoke, hotspots, burn scars and fire weather index over the last 72 hours, in 1 hour increments. Choose your trail. www.postholer.com/trail-fires
More evidence against El Nino hype. Looking at the last 22 years, there's no evidence strong/moderate El Nino contributes to wetter weather. Only 2 of the top 10 years were moderate. 6 were Nina's!!! The opposite seems to be true in a changing climate.
Sierra Snow animation on May 28th, from 2004 to 2026. www.postholer.com
El Nino: Hazard or hype? Social media is awash with "weather wandas" seeking clicks, professing doom & gloom about El Nino. Here's a look over the years of its impact in California, in terms of precipitation.
967 distinct eco-regions from the @EPA for CONUS, levels 1-4. That's 5,842 at level 4. Base map turned off for clarity. Zoom in to increase eco-region level. Click for name: www.postholer.com/map/Pacific-...
It seems folks are struggling with @fema Flood Hazard (NFHL) data. Create your own spatial database, allowing you to query by FIRMID, FIPS, community id, date, geometry and retrieve data in bulk: postholer.com/portfolio/no... @cloudnativegeo.org @radiant.earth @briannaritapagan.bsky.social
Here's a GDAL only version of your parquet parcels example:
Here's the 11/13 23:00 3 day NBM QPF forecast compared to actual precip. Red means NBM over-stated (in inches):
Here's an interactive map with the same data. Double-click anywhere to get the annual precipitation for an exact location: www.femafhz.com/map/48.62379...
Comparison of NBM QPF (precipitation) forecast model vs actual QPF amounts, for 2 events, Oct 24-27 and Nov 04-06 2025 along the California north coast. Consistency is an issue. @nws.noaa.gov #weather #california
National Risk Index, Riverine Flooding - Expected Annual Loss Rate - National Percentile shown. Choose category by state, county or census tract #polygons. www.femafhz.com/map/35.13787... #30DayMapChallenge
Using PostGIS ST_LineInterpolatePoints to evenly get points from line features (roads) and ST_ClusterDBScan to get (mostly) non-overlapping points for road shields on interactive map. Using only st_clusterdbscan for non-overlaping GNIS place names. #30DayMapChallenge #points #postgis #leafletjs
Here's a National Risk Index map for those disasters, except interactive, at state, county, census tract level for 24 different categories and 20+ metrics, percentile, expected annual loss, etc ,etc. 2022 data. Riverine Flooding shown: www.femafhz.com/map/36.98500...
Fully interactive map of #Melissa, with the most up-to-date NHC data: www.femafhz.com/map/19.43551...
Here's the same result using only #GDAL, cutting out the python nastiness: Simplify: gdal vector simplify --input=states.gpkg --tolerance=.5 --output=simple.gpkg Clean coverage: gdal vector clean-coverage --input=simple.gpkg --snapping-distance=.7 --output=clleaned.gpkg
#Melissa Cat 2-4, Sun 8am to Tues 8am, with Jamaica on the right hand side of the storm, 50km away. Brutal. www.femafhz.com/map/17.66233...