QGIS
Basemap Rendering in QGIS: Overview A basemap in QGIS provides spatial context and orientation for overlaying other geospatial data layers. Basemaps enable users to visually locate and reference features and locations. Common basemap types include street maps, topographic maps, satellite/aerial imagery, and blank canvases. QGIS offers several options for loading basemaps: Core native capabilities like…
What is a Geometry Expression? A geometry expression in QGIS is a textual definition of a geometric shape using functions and operators. They provide a flexible and powerful way to construct custom polygon vector layers without needing to create or edit the underlying geometry manually. Geometry expressions allow users to define polygons by specifying vertices,…
Geometry errors in spatial data can cause a variety of issues when working with QGIS. Identifying and resolving these errors is an important troubleshooting skill for effective QGIS usage. This article provides tips and tricks for debugging common geometry generation issues in QGIS. Identifying Geometry Issues in QGIS The first step in fixing geometry errors…
Troubles with Geometry Creation When working with geospatial data in QGIS, users can encounter various issues when creating and editing vector geometries. Invalid geometries, limitations of geometry tools, and failures to follow best practices often undermine efforts to accurately model real-world spatial entities. Invalid Geometries and How to Fix Them Invalid geometries refer to vector…
What are Geometry Expressions and Why Learn Them? Geometry expressions in QGIS provide a powerful set of tools for performing spatial analysis and manipulating geographic data directly within the QGIS interface. They allow users to calculate geometric properties like area and length, test spatial relationships between features, construct new geometries from existing ones, and filter…
The Problem: Tedious Manual Processing for Batch Transformations When working with geographic data, one common task is to reproject multiple data layers from one coordinate reference system (CRS) to another. This allows disparate datasets using different CRSs to be viewed and analyzed together within the same reference system in applications like QGIS. However, reprojecting many…
Identifying the Printing Bug As a powerful open source geographic information system (GIS) software, QGIS offers robust map printing capabilities for users. However, common bugs in the print process may impact your ability to generate high-quality printed outputs. Detecting the type of printing issue is the first step towards corrective fixes. Key clues to the…
The Problem: Buffers Created in Degrees Instead of Meters A common issue when working with geospatial data in QGIS is that distance and area calculations can unexpectedly be returned in geographic degrees instead of projected units like meters. This happens frequently when using the Buffer tool to create buffer zones around vector features. For example,…
Viewing Layer Attribute Tables The first step in extracting coordinates from a vector layer in QGIS is to view the layer’s attribute table. The attribute table displays the data attributes associated with each feature in the layer, including any coordinate fields. To view the attribute table for a layer: Right click on the layer name…
Troubleshooting QGIS Python Issues on Windows Locating the Cause When issues arise with PyQGIS scripts on Windows, the first step is identifying the root cause. Check any error messages output to the console or logs for clues. Error messages indicating file paths, access issues, or version conflicts can help narrow things down. If a particular…
