Transcript
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Mapping session
LIWG
02.03.2012
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Contents
• Introduction • Working with existing vector data Open the program and add layers Tools Change properties of the layers Save a project Layouting maps
• Working with the attribute tableCalculating geometriesField Caluculator
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Contents
• Creating new shape files Adding an event layer (Coordinates from the GPS) Creating a new point/ line/ polygon shape file Creating a new shape file from selected features
• Analysis Tools BufferJoin and Union
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What is QGIS and what we can do with it?
Geographic Information System for managing geographic information
Collection, management, analysis and presentation of geospatial data
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VECTOR and RASTER DATA
• Vector and raster are data formats used to store geospatial data!
• Vector data use X and Y coordinates to define the locations of points, lines, and areas (polygons) that correspond to map features such as fire hydrants, trails, and parcels spatial details
• Standard GIS data: Shape file stores both spatial data and their attributes
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VECTOR and RASTER DATA• Raster data use a matrix of square
areas (pixels, cells, and grids) to define where features are located. The squares are typically of uniform size and their size determines the detail that can be maintained in the dataset. Because raster data represent square areas, they describe interiors rather than boundaries as is the case with vector data
– data such as elevation, temperature, soil pH, etc. that vary continuously from location to location
– aerial and satellite imagery
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VECTOR and RASTER DATA
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The layer-concept
Every layer has a different theme!
In every layer there are only elements of one type (points, lines, polygons, raster)!
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Open the program
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Add layer
1. Click „Add layer“-button
2. Click „Browes“
3. Click Location Shp
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Add layer
Table of contents
taskbar
Display window
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Add layer
A layer shape file = geospatial vector data format for geographic information systems software
It contains different files:
.dbf store feature attribute data every layer has a attribute table
.prj specifies the geographic coordinate system
.shp contains the primary geographic reference data feature geometry
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Add layer
If you want to work with a layer activate the layer by clicking on it!
Not active
Active
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Navigation Tools
Moving the mouse over the buttons see what you can do with them
Previous Zoom
Zoom in Zoom out
Full extent Zoom to layerPan map
Zoom to selection
Next Zoom
Dereferencing
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Dereferencing
16Transformation settings Start georeferencing
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Creating a new layer
• Creating a new shape file
• Edit shpe file
• Creating a new shpe file from selected features
Creating a new layer
18New shapefile layer
Creating a new layer
19New shapefile layer Cut proligon
Edit shapefile layer & field caculator
20 Merge selection features Field caculator
Field caculator
21 Click open field calculator Area calculatot HA
Creating a new shpe file from
selected features
22 Click save as selected Select coordinet system
New layer form PLMA map
23New shapefile Area PLMA approve
PLMA map & NLMA2010_SVK_Concessions
24Point Concessions area NLMA
Overlap PLMA appove and GPS planted area
25GPS data Way point and Track
Overlap PLMA appove and area planted
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Overlap PLMA appove and area planted
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Land clearance do not follow Area permission
Area planted Overlap with image
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Compare PULP HXY village NAFES Map JVC Map
By/Mr SengchanPHOMMACHANH
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