gemgis

gemgis is a skill for Claude Code, Codex from SteadfastAsArt/geoscience-skills. It costs 102 tokens per session (1,522 once invoked), scanned A, original, MIT.

A Python toolkit for preparing maps, elevation rasters, and structural measurements for geological models made with GemPy.

In plain words
What is it for?
Use it to extract XYZ points from geological features and digital elevation models, process dip and orientation measurements, clip map data, sample elevation profiles, and convert GIS data.
Why use it?
It reduces the manual work of aligning geographic data and extracting the three-dimensional coordinates needed by a model.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to extract XYZ points from geological features and digital elevation models, process dip and orientation measurements, clip map data, sample elevation profiles, and convert GIS data.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/steadfastasart/geoscience-skills/gemgis
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add SteadfastAsArt/geoscience-skills --skill gemgis
Clone the repo
git clone --depth 1 https://github.com/SteadfastAsArt/geoscience-skills

Made for: Claude Code, Codex.

Its marketplace also offers this one on its own, as the plugin gemgis/plugin install gemgis after adding the marketplace above.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for gemgis

README.md
[![agentmods](https://agentmods.dev/badge/skills/steadfastasart/geoscience-skills/gemgis/github.svg)](https://agentmods.dev/skills/steadfastasart/geoscience-skills/gemgis)
Your own site
<a href="https://agentmods.dev/skills/steadfastasart/geoscience-skills/gemgis"><img src="https://agentmods.dev/badge/skills/steadfastasart/geoscience-skills/gemgis/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for gemgis

Your own site · 80×15
<a href="https://agentmods.dev/skills/steadfastasart/geoscience-skills/gemgis"><img src="https://agentmods.dev/badge/skills/steadfastasart/geoscience-skills/gemgis.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 102 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,522 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00102 $0.01522
Opus 5 $0.00051 $0.00761
Sonnet 5 $0.00020 $0.00304
Haiku 4.5 $0.00010 $0.00152

Measured 9d ago against content hash f1e634bced9d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

gemgis scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/prepare_gempy_data.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

gemgis/SKILL.md · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

GemGIS - Geospatial Data for Geological Modelling

Quick Reference

import gemgis as gg
import geopandas as gpd

# Load vector data
gdf = gpd.read_file('geology.shp')

# Extract XYZ from geometry with elevation from DEM
interfaces = gg.vector.extract_xyz(gdf=gdf, dem='dem.tif')

# Define model extent
extent = [x_min, x_max, y_min, y_max]

# Clip to extent
gdf_clipped = gg.vector.clip_by_extent(gdf=gdf, extent=extent)

Key Modules

Module Purpose
gemgis.vector Vector data processing, XYZ extraction
gemgis.raster Raster/DEM processing, sampling, interpolation
gemgis.utils Utility functions, extent management
gemgis.postprocessing Model postprocessing

Essential Operations

Extract Interface Points

contacts = gpd.read_file('contacts.shp')
interfaces = gg.vector.extract_xyz(gdf=contacts, dem='dem.tif')
interfaces['formation'] = contacts['formation']
# Returns DataFrame with X, Y, Z, formation columns

Extract Orientations

measurements = gpd.read_file('structural_measurements.shp')
orientations = gg.vector.extract_xyz(gdf=measurements, dem='dem.tif')
orientations['dip'] = measurements['dip']
orientations['azimuth'] = measurements['strike'] + 90  # strike to dip direction
orientations['formation'] = measurements['formation']

Sample DEM Along Profile

profile = gg.raster.sample_from_raster(
    raster='dem.tif',
    line=[(500000, 5600000), (510000, 5605000)],
    n_samples=100
)
# Returns dict with 'distance' and 'Z' arrays

Define Model Extent

# From coordinates
extent = gg.utils.set_extent(
    x_min=500000, x_max=510000,
    y_min=5600000, y_max=5610000
)

# From GeoDataFrame bounds
extent = gg.utils.set_extent_from_bounds(gdf)

Clip Data to Extent

from shapely.geometry import box
extent_poly = box(500000, 5600000, 510000, 5610000)
gdf_clipped = gdf.clip(extent_poly)

# Or using gemgis
gdf_clipped = gg.vector.clip_by_extent(
    gdf=gdf,
    extent=[500000, 510000, 5600000, 5610000]
)

Read the full file on GitHub · 177 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 177 lines · 102 tokens per session scan A f1e634bced9d

Subscribe to this mod's changes

gemgis is a skill published in the GitHub repository SteadfastAsArt/geoscience-skills (57 stars, last pushed 5mo ago), licensed MIT. It adds 102 tokens to every session and 1,522 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

gdal

Use when processing geospatial raster/vector data via command line — format conversion (Shapefile to GeoJSON), reprojection, DEM analysis, NDVI calculation, mosaicking. GDAL/OGR CLI: the industry standard for batch geospatial data processing with 50+ command-line tools (ogr2ogr, gdalwarp, gdaltranslate, gdalcalc).

znlgis/opengis-skills · 77 tokens

gis-skills

Use when processing geospatial data, publishing map services, querying spatial databases, performing geometry operations, or building web map applications. Index of 23 skills: GDAL, GeoServer, QGIS, PostGIS, JTS, GeoPandas, Shapely, CesiumJS, OpenLayers, NetTopologySuite and more.

znlgis/opengis-skills · 71 tokens

soil-data

Soil data analysis via SoilGrids 2.0 REST API and SSURGO: SOC stocks, texture classification, kriging interpolation, and soil profile visualization.

xjtulyc/awesome-rosetta-skills · 37 tokens

open-map-stack

Use textual agent instructions for GIS and geospatial work: source discovery and provenance, vector/raster/point-cloud pipelines, CRS and metric analysis, spatial SQL, routing and isochrones, QGIS projects, tile generation, and web maps. Use advanced tools and formats such as OSM, Overture, STAC, Sentinel/Landsat…

jaakla/openmapstack · 169 tokens

opengis-skills

Use when AI coding assistant needs GIS/CAD/C#/AI/IoT/3D domain expertise for 73+ open-source projects. One-stop skill index with tag-based search and on-demand loading for GDAL, GeoServer, QGIS, PostGIS, JTS, CesiumJS, FreeCAD, OpenSCAD, OCCT, NPOI, SqlSugar, Furion, Dify, SuperSplat, Go and more.

znlgis/opengis-skills · 97 tokens

gdal-api

Use when programming against GDAL/OGR in C, C++, Python, or .NET for raster/vector I/O, coordinate transformation, or custom geospatial algorithms. GDAL API: low-level programming interface for reading/writing 70+ geospatial formats.

znlgis/opengis-skills · 56 tokens