Projection is the process of transformation of higher dimensional space (3D) into a lower dimensional space (2D). If we talk about measurement, Projected coordinate system is more accurate than Geographic coordinate system. It is one of the frequently done task in GIS.
There are many methods or sources for obtaining contour like cartographic source (digitalization of old topo map), stereo-pairs, lidar data, photogrammetric methods, GIS softwares etc.
One of the data source for contour is Digital Elevation Model (DEM). In this tutorial we will learn how we can get contour through DEM in QGIS. Follow the following steps:
The main objective of this tutorial is to learn technique of generating slope from DEM. After getting slope we will also reclassify slope. We are going to do this in QGIS.
Have you ever seen a map? What do you see? You see color, shape, some text, symbols or icons, geographic reference layers and some other thing that tries to give some message. Map presents some information from the data.
Can you read a map? Professionally I’m a Cartographer and frequently show my maps to my friends. Somehow they manage to get the information from the map but they don’t understand all the things given in the map.
Our LULC raster has DN values in its pixels and we have labeled it by symbology under different classes like ‘WaterBodies’, ‘Forest’, ‘Urban’ etc. But unlike vectors we can’t directly store values in raster creating a new field in open attribute table explaining DN ‘1’ means ‘WaterBodies’ or something like that. Also raster with DN value meanings(like forest, urban etc.) can be used later to give rank to different classes in Multicriteria Decision Analysis.
