Mastodawn

Dear #history folks: I'm a professional mapmaker (https://somethingaboutmaps.com) and I make a lot of maps for academic press books.

Would you be interested in attending an online talk where I discuss:
• what cartographers are
• why your work might benefit from maps
• how to find a mapmaker
• what it's like to work with one
• how much it might cost
?

If there's enough interest, I might put something together this winter, so please boost this! If it happens, I'll announce it here and on my blog.

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gistinker Oct 16

@juergen_hubert I would take the image and assign Ground Control Points at the same spacing as decimal degree Lat/Long coordinates using GDAL see, https://livebook.manning.com/book/geoprocessing-with-python/chapter-10#23

Chapter 10. Working with raster data · Geoprocessing with Python

Georeferencing with ground control points · Working with attributes, histograms, and color tables · Using the GDAL virtual format · Reprojecting rasters · Using GDAL error handling

gistinker Oct 13

jakalopes Aug 6, 2025

I came across this awesome website with (mostly) free to use silhouette images of different organisms - great for scientific publications and presentations! I really appreciate people making/uploading these images for others to use - will probably be using these on graphs in the future. The bee species available are a bit lacking, though.
https://www.phylopic.org/

#science #biology #entomology #bees #research #academia #ScienceResources

gistinker Oct 13

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Keith Jenkins Oct 12

Thanks again to @nyalld for adding "chains" as a distance unit in #QGIS

Today I'm using it to find and fix errors in the survey journal for the town of Ulysses that dates from 1790...

gistinker Oct 9

Hydroflattening tutorial for LiDAR data using GRASS on Zenodo. Added appendix for Windows users to show how to create a mean ground layer from virtual point clouds in QGIS for input to r.hydro.flatten using the version of GRASS that comes with the QGIS standalone installer. QL2 or better LiDAR data works best.

Another option on Windows would be to use pdal directly to create a mean ground layer, but my pdal expertise does not extend that far, yet.

https://zenodo.org/records/17121433

A Tutorial on Modeling Water Voids in Airborne LiDAR Point Cloud Data to Hydroflatten Water Surfaces in Digital Elevation Models.

This is a step-by-step tutorial on how to use the GRASS r.hydro.flatten Addon to accurately model water surfaces from airborne LiDAR point cloud ground data, including creating a complete DEM . Directions are given for using the tutorial in both Linux and Windows.

Zenodo

gistinker Jun 25, 2025

Jürgen E. Fischer 🇪🇺🇺🇦Jun 23, 2025

Linux and Windows packages of #QGIS release 3.40.8 "Bratislava" (LTR) and 3.44.0 "Solothurn" (RC) ready on https://qgis.org. Make maps not war!

gistinker Jun 25, 2025

Randal Hale (He/Him)Jun 24, 2025

QGIS is crowdfunding Digital Twins: https://www.lutraconsulting.co.uk/crowdfunding/qgis-3d-for-open-source-digital-twins #qgis #foss4g

QGIS 3D for Open Source Digital Twins | Lutra Consulting

Join our crowdfunding campaign to enhance QGIS 3D tools for open-source digital twins, bringing improved performance, features, and community-driven innovation.

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gistinker Jun 25, 2025

@rjhale1971 Yeah, wouldn't want to make it easy to put data in a publicly documented format.

gistinker Jun 2, 2025

On the other hand, if the polygon does not represent a single elevation value, You can convert the polygon to a "stream" by extracting the z values from the DTM for each Vertex and creating a surface from those points ,(masked to the polygon) then run GRASS GIS r.hand, https://grass.osgeo.org/grass-stable/manuals/addons/r.hand.html to flood to 2 meters around the polygon.

r.hand - GRASS GIS manual

r.hand: Performs Height Above Nearest Drainage (HAND) analysis and flood inundation mapping with HAND method.

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gistinker Jun 2, 2025

@sarahdalgulls @rjhale1971
If the polygon represents a water body that you know the elevation of , then just subtract the elevation of the water body from the DTM and make a 2m contour line.