Links « Contour Education Interactive Maps Ordnance Survey MapZone This is a brilliant site that is perfect for introducing your students (all ages) and staff to the basic concepts behind GIS software. The site contains lots of information on what GIS is, how it is used in the real world as well as links to helpful sites. The best feature though is the GIS missions – or GIS games. Protected Planet This brilliant site lets you search a visual catalogue of the world’s protected areas. kmlfactbook.org The kmlfactbook.org page takes some of the global data available in the CIA World Factbook and displays it over a 2D or 3D map of the world. Map of Life The Map of Life is a well-supported project that organises data on species ranges over a range of beautifully designed basemaps. WWF Wildfinder The WWF Wildfinder allows your students to enter the common name of an animal and view its geographic extent. Geoscience Australia Sentinel Old Maps Online Maps of War ShowRWorld Online Global Reefs Map Online Map Editors Google Maps
Digitizing Errors in GIS Digitizing in GIS is the process of converting geographic data either from a hardcopy or a scanned image into vector data by tracing the features. During the digitzing process, features from the traced map or image are captured as coordinates in either point, line, or polygon format. Types of Digitizing in GIS There are several types of digitizing methods. Types of Digitizing Errors in GIS Since most common methods of digitizing involve the interpretation of geographic features via the human hand, there are several types of errors that can occur during the course of capturing the data. During the digitizing process, vectors are connected to other lines by a node, which marks the point of intersection. Dangles or Dangling Nodes Dangles or dangling nodes are lines that are not connected but should be. An open polygon caused by the endpoints not snapping together. Switchbacks, Knots, and Loops Example of a weird polygon where the line folds back on itself. Overshoots and Undershoots Slivers
Open Source GIS Working with Coordinate Systems The great thing about geographic information systems is that data from different sources can be juxtaposed, according to the way that each is related to the suface of the planet -- and new information emerges about possible realtionships. This is made possible by spatial referencing systems such as Latitude and Longitude or projected coordinate systems. Software is getting better at aligning images and layers that are referenced in different coordinate systems, nevertheless we often encounter problems getting layers to line up as they should. This document provides some tips for troubleshooting and fixing alignment problems with spatial data. Topics Covered in this Document Related Documents Aligning GIS Data Layers in ArcGIS GIS databases organize information about observations with information about location. Assessing a Non-alignment Problem Most of the time ArcMap is able to load different layers and to project them apropriately. Inspect Layer Properties Identifying a Coordinate System