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QGIS Training.pptx

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QGIS Training.pptx

  1. 1. This software is the popular QGIS open source GIS software. In this you will learn how to load data into QGIS from popular GIS formats including shapefiles, geodatavases. And how to classify features and capturing roads and buildings etc.., Course Introduction
  2. 2. An Overview of the Interface We will explore the QGIS user interface so that you are familiar with the menus, toolbars,map canvas and layers list that form the basic structure of the interface. The elements identified in the figure above are: •Layers List / Browser Panel •Toolbars •Map canvas •Status bar •Side Toolbar
  3. 3. Exercise data This module is basically where we do the ‘nitty-gritty’ part of the GIS training to come-up with final outputs. You will learn how to obtain, create, manipulate, edit geospatial data by series of tools and commands. The exercises will be done step by step, along with actual demonstration. The exercises will make you “connect” the theoretical part of GIS to its actual applications. Data source may take from web maps.
  4. 4. Creating a Basic Map Vector Vector data is not made up of a grid of pixels. Instead, vector graphics are comprised of vertices and paths.The three basic symbol types for vector data are points, lines and polygons (areas). These cartographers use these symbols to represent real world features in maps. Points When features are too small to be represented as point is used. For example trees, transmission towers and overhead tanks are represented by point feature.
  5. 5. Polylines Vector lines connect each vertex with paths. Basically we are connecting the dots in a set order and it becomes a vector line with each dot representing a vertex. Lines usually represent features that are linear in nature. For example maps shows roads, culverts, bridges, canals and rivers (depends on width) and flyovers. Here lines are represented by red colour.
  6. 6. Polygons When we join a set of vertices in a particular order and close it, this is now a vetor polygon feature. Cartographers use polygons to show boundaries and they all have an area. For example, a building footpriny has a square footage and agricultural fields and village abadis haing areas. Captured buildings by using rectangular polygons.
  7. 7. Vertex click on a vertex or segment to enable vertex editing for that feature. Click on vertex you want to add and move node points.
  8. 8. Scale The scale is a simple ratio of map to ground measurement with a colon between the two measurements. For example, a scale of 1:1000 means that every one unit on the map is equal to 1000 units on the ground. Maximum we digitize date within the range of 1000.
  9. 9. Symbology It is the application of graphic symbols, varied by subclasses, width and other properties.
  10. 10. Adding layers Open manage layers toolbar (it exist in left side of the screen). Or open data source manage toolbar. In that we have a new shape file layer.
  11. 11. Then create a layer which geometry needed and give file name and create path in your folders.
  12. 12. Creating Vector Data Feature topology Topology is a useful aspect of vector data layers, because it minimizes errors such as overlap or gaps. For example: if two features share a border, and we edit the border using topology, then you won’t need to edit first one feature, then another, and carefully line up the borders so that they match. Instead, we can edit their shared bored and both feature will change at the same time. Here when we see on the image these are the line rules.
  13. 13. Here these are the polygon rules. By using these rules we can run topology
  14. 14. Digitization Digitization is a process of converting raster data to vector data. For this process QGIS provides many tools for efficient digitization. Digitization should be clean and a copy of the raster data so that the information of the map does not change. For example digitization of roads and building
  15. 15. Errors detection When we run the topology rules the errors should find in topology check panel if errors should be there. Errors can be finding by red marks on vector data.
  16. 16. Attribute data It is used to describe the feature that you want to map. It can include text or numbers data type. Must be careful in how the different data types are integrated and used.
  17. 17. Label tool Map is not just a picture in GIS, they represent several hidden information of objects. So in the upcoming days we try to understand it more and unearth the hidden data. After creating basic map, we try our hands on layer labeling in QGIS use and change label. For extracting more information about the object we do labeling.
  18. 18. Classification Image classification is one of the most important tasks in image processing and analysis. It is used to analyze land use and land cover classes. With the help of remote sensing we get satellite images such as landsat satellite images.
  19. 19. Any Queries

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