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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