QGIS provides two methods for creating geometries using expressions: Geometry Generator (introduced in QGIS 2.14) and Geometry by Expression (introduced in QGIS 3.0). Both leverage QGIS's expression engine but serve fundamentally different purposes. This tutorial clarifies their differences and appropriate use cases.
In a previous article "Geo Hound: A Tool to Automatically Fetch Website Map Service Addresses", I introduced the powerful Geo Hound tool. Follow-up articles like "Get Hidden Government Map Data in 2 Steps (Geo Hound + Wuhan One Map)" and "Shanghai One Map Data (Trial)" shared practical experiences. Many readers subsequently asked: Can this map data be downloaded for offline use? While various methods exist, I'll share my two most-used approaches.
Extracting river/canal centerlines is a common task in GIS data processing. Users of ArcMap or ArcGIS Pro likely find it straightforward. Recently, many colleagues have started exploring QGIS, someone in My GIS Group asked about this, making it a good time to document the process.
PS: The author will focus on introducing methods to achieve ArcGIS-equivalent functions in QGIS. If you have specific needs in this area, feel free to leave a comment.
QGIS 3.44 has now been officially released. I downloaded and tried it out immediately. For Windows users, QGIS 3.44 offers both a test version with Qt6 support ("Latest Version for Windows (3.44) with Qt6 (experimental)") and the standard 3.44 version ("Latest Version for Windows (3.44)").
Recently in the Mala GIS group, someone raised an interesting question: Can GIS be used to analyze which province in China has produced the most leaders? Previously, you might have had to search via a search engine, but the data might not be up-to-date, and quantitative analysis would be cumbersome, requiring tedious data cleaning. However, in the AI era, we can easily accomplish this task using AI + GIS.
P.S.: This article is purely technical, and the data may not be entirely accurate. Corrections are welcome if any issues are found.
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