Finding and using the data behind web maps.
Public web maps are full of data that is technically available and practically hidden. These are the working notes: how to find the service behind a viewer, how to get it into the software you use, and how to answer a question with it. Most of it is doable by hand. Geo Hound just makes it quick.
Finding the data
Getting the service URL out of a web map that was not built to give it to you.
How to find the WMS URL behind a web map
The service URL is in the network traffic. Here are three ways to get it out, from slowest to fastest.
How to get the data out of an ArcGIS web map
ArcGIS viewers hide the REST endpoint, but the browser has already loaded it. Here is how to get at it.
How to extract GIS data from a website
What can and cannot be extracted from a public web map, and how to do the part that can.
How to find the XYZ tile URL a map is using
Slippy maps request tiles by z/x/y. Find one request and you have the whole template.
What GetCapabilities tells you about a WMS or WFS
The self-describing document behind every OGC service, and the four things worth reading in it.
Using the data
Once you have the URL, getting it into the software you actually work in.
How to open an ArcGIS FeatureServer in QGIS
QGIS speaks ArcGIS REST natively. The trick is knowing which part of the URL to give it.
How to download GeoJSON or KML from a web map
Getting the file, and getting only the part of it you need rather than the whole country.
Why a map service will not load in a browser app (CORS)
The service works in QGIS but not in your web app. Almost always, this is why.
FeatureServer vs MapServer: which one gives you the data?
One serves pictures, one serves features. Knowing which you are looking at saves an hour.
Analysing the data
Answering a question with the data, with or without desktop GIS.
How to do GIS analysis without installing QGIS
What you can genuinely do in a browser tab, and the honest limits of it.
Talking to a map: what an AI GIS assistant can actually do
Ask a question in plain English, get a map and a number back. What that really means in practice.
How to buffer features and count what falls inside
The single most common GIS task, done three ways depending on what you have installed.