ILWIS – Integrated Land and Water Information Management
ILWIS is free (GNU license) for users around the world for GIS and remote sensing needs. Here are some of the neat features and developments.
Articles
Scale Bars, Inset Maps and Ratio Text in Cartography
There are several ways to help readers understand map scale and distance. For example, cartographers use scale bars, locator maps, stated and ratio scale.
Latitude, Longitude and Coordinate System Grids
Latitude lines run east-west, are parallel and go from -90 to +90. Longitude lines run north-south, converge at the poles and are from -180 to +180.
ArcScene vs ArcGlobe – Esri’s 3D GIS Software Differences
ArcScene and ArcGlobe both specialize in 3D. However, ArcScene is for local scenes and ArcGlobe is for global. Find out more differences between 3D software.
Linear Referencing Systems (LRS)
Linear referencing systems (LRS) store relative positions on an existing line feature with m-values for point/line events and linear analysis.
Polar Orbit vs Sun Synchronous Orbit
A polar orbit satellite travels pole-to-pole. For a sun-synchronous orbit, it passes over any given point on Earth’s surface at the same local solar time.
What is NDVI (Normalized Difference Vegetation Index)?
NDVI quantifies vegetation health using near-infrared (which is reflected by vegetation) and red light (which is absorbed by vegetation).
Georeferencing: How to Georeference Images
Learn how to georeference with precision in this georeferencing guide. Add control points in two images, select a transformation and check your RMSE.
What is GIScience (Geographic Information Science)?
While Geographic Information Systems answers “what” and “where”, Geographic Information Science (GIScience) is concerned with the “how” and its development.
Conic Projection: Lambert, Albers and Polyconic
When you place a cone on the Earth and unwrap it, this results in a conic projection. Examples are Albers Equal Area Conic and the Lambert Conformal Conic.