Introduction to QGIS

Transcription

1 Introduction to QGIS David Kramar, Ph.D. Minnesota State University Moorhead Department of Anthropology and Earth Science

2 Overview of Workshop What is QGIS? How do I get QGIS The QGIS GUI Basic Geoprocessing Additional Plugins Saga, Grass, and R The Print Composer

3 What is QGIS? In short It is a flexible, capable, and powerful open source solution! QGIS started as a viewing environment for Linux, But integrates with Windows and Mac. Supports MANY data formats and works well with PostGreSQL and PostGIS layers.

4 What is QGIS? Open Source and Powerful All basic, and most advanced GIS functionality Supports a plethora of data formats Extendable and Highly customizable Includes comprehensive Analytic capabilities e.g. Processing Tools and Modeler Can be customized and automated via: Python scritpting Supports plug-in and user interface development Rapid Development from community!!

5 The Open Source Culture In many cases, business folks do not understand why some people would Create something useful and then just give it away. For that reason, open source software solutions are often viewed as less robust, less functional, and less compatible. That could not be further from the truth. The OS culture is a way of doing things, of working together. It is a culture. It is generally assumed that if you are using the software, you will give back to the community via Support pages, new plug-ins, customizations, etc. The more people work together, the stronger the community becomes.

6 How do I get QGIS? download.html Most current version is QGIS 2.18: Las Palmas Download the installer and GO!! Note: There was an issue with Python from the ArcGIS 10.4 Install that created issues with QGIS. That appears to be resolved with 10.5

7 The Graphic User Interface

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10 Most of the buttons/toolbars are self-explanatory if you are familiar with other GIS packages, however some are not as intuitive as we may like..best is to just explore them. Project Toolbar Map Navigation Toolbar Labeling Toolbar Digitizing Toolbar Attributes Toolbar Manage Layers Toolbar Advanced Digitizing Toolbar

11 Setting Up Project Properties

12 Setting Up Project Properties

13 Setting Up Vector Layer Properties - General

14 Setting Up Vector Layer Properties - Symbology Units can be millimeters, Map Units, or Map Pixels

15 Setting Up Vector Layer Properties - Symbology In general Symbology is a shortcoming when compared to ArcGIS, which can make the cartography portion of GIS a bit exhausting. With that being said, there is a plugin called Resource Sharing that expands the basic symbol sets in QGIS. While I still argue that symbol sets are limited compared to ArcGIS, they are getting better all the time. To access them, change the symbology type from simple marker to.. And then browse to your symbol sets.

16 Setting Up Vector Layer Properties - Labels

17 Setting Up Vector Layer Properties - Fields

18 Setting Up Vector Layer Properties - Fields

19 Setting Up Vector Layer Properties - Rendering

20 Setting Up Vector Layer Properties - Rendering

21 Calculating Attribute Values and Working with Tables Not as intuitive as calculating in ArcMap. Fields can be added via the Attribute Table, or through the Field Calculator. You can Create New, Update Existing, or Create Virtual Fields (Field Calculator) MUST be in Edit Mode to add a field Simple enough: Just toggle Editing on or off. Two ways to view attribute data: Table View, or Form View.

22 Calculating Attribute Values and Working with Tables To calculate area (in the CRS the layer is in): Open Attribute Table (Lakes for this example) Toggle Editing Either Add Field First, or open Field Calculator and Add through that Dialog.

23 Calculating Attribute Values and Working with Tables To calculate area (in the CRS the layer is in): Open Attribute Table (Lakes for this example) Toggle Editing Either Add Field First, or open Field Calculator and Add through that Dialog.

24 Calculating Attribute Values and Working with Tables To calculate area (in the CRS the layer is in): Open Attribute Table (Lakes for this example) Toggle Editing Either Add Field First, or open Field Calculator and Add through that Dialog. Perimeter is calculated in much the same fashion. To convert to something other than meters, just Include that in the calculation. For example If CRS units are meters: $AREA / = KM

25 Calculating Attribute Values and Working with Tables To calculate area (in the CRS the layer is in): Open Attribute Table (Lakes for this example) Toggle Editing Either Add Field First, or open Field Calculator and Add through that Dialog. Perimeter is calculated in much the same fashion. To convert to something other than meters, just Include that in the calculation. For example If CRS units are meters: $AREA / = SQ KM Similarly for Perimeter: $PERIMETER / 1000 = KM

26 Calculating Attribute Values and Working with Tables To calculate based on OTHER FIELDS: Add a Field (Compactness) Fields and Values Dropdown Double click fields and build expression.

27 Joining Tables in QGIS To Join tables based on common fields: Joins are completed from the Layer Properties Dialog. Not that dissimilar from ArcGIS. Specify the Join Layer and Join Field, and then Specify the Target Field So: Click + Button to Add a Join

28 Spatial Joins in QGIS To create a spatial join: Vector Data Management Tools Join Attributes By Location Select Target Vector Layer Select Join Vector Layer Select Geometric Predicate Specify Type of Attribute Summary Specify Statistics to compute (Optional) Specify Whether to Keep Only Matching Create Virtual layer, or Real Layer?

29 Geoprocessing, Research, Analysis Tools in QGIS GeoProcessing Options are Similar to ArcMap: Research Tools: Analysis Tools: Geometry Tools:

30 Expanding Vector Processing in QGIS The Processing Toolbox: There is no shortage of vector based analysis tools in the processing toolbox. In some respects there are many of the same types of operations that can be found in ArcGIS. When fully integrated with GRASS and R, however, there are many more statistical based operators. Same is true for Raster Operations.

31 Expanding Vector Processing in QGIS Working with Plugins: If for some reason you cannot find what you are looking for in the standard Processing Plugin, there are a number of resources via the Plugin Manager. Clicking on any PlugIn will give you an overview of the Plugin functionality.

32 Expanding Vector Processing in QGIS

33 Managing your Raster Data There are a number of different ways to manage your raster data in QGIS. Most typical options are found in the Raster Menu Item we discussed earlier. For example to build raster pyramids, you would go to Raster Miscellaneous Build Overviews (Pyramids). To Merge rasters you go to Raster Miscellaneous Merge Additional Raster Operations are found in the processing toolbox plugin.

34 QGIS + R Package (Statistical Software) Official R webpage and download links R Studio Articles AND Scripts - R + Geospatial use Geospatial data in R and Beyond R, an Integrated Statistical Programming Environment and GIS Spatial data and R QGIS-R-Geostatistics scripts contribution R scripts and GIS integration R-scripts in Processing "Spatial data processing framework for QGIS" Plug-in (formerly Sextante plug-in) Needs to be enabled in Processing menu / providers: After R is enabled (and installed on your operating system) you can run the scripts from the Processing Toolbox see next page

35 QGIS Processing Toolbox Enabling R Package (Statistical Software)

36 QGIS Processing Toolbox Enabling R Package (Statistical Software) The first thing you have to do is to tell QGIS where your R binaries are located. You can do this using the R folder entry in the processing configuration dialog. Once you have set that parameter, you can start creating and executing your own R scripts. On my computer, they are located at: C:\Program Files\R\R-3.3.1

37 The QGIS Print Composer Making Maps in QGIS is a little different than in ArcGIS. There is no Toggle between layout and data view. To access: Project New Print Composer What is the first thing you notice??

38 The QGIS Print Composer Making Maps in QGIS is a little different than in ArcGIS. There is no Toggle between layout and data view. To access: Project New Print Composer What is the first thing you notice?? No Map!! You have to add the map: Layout Add Map No Dynamic Zoom in/out. You MUST get your extent set in the browser and THEN add it to the composer. See Example.. Accessing Item Properties is a bit different To remove Items from legend you can t just Turn it off in the Browser. Lacks the dynamic flexibility if you are used to ArcGIS, but does other neat things.

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40 To re-center content, use the Move Content Option.

41 Select Map Adjust Scale HERE to zoom in or out

42 One neat feature of the Print Composer is that it can automatically highlight the area from the main map which is represented in our inset. Select the Map 0 (main map) object from the Items panel. In the Item properties tab, scroll down to the Overviews section. Click the Add a new overview button. Select Map1 for your Map Frame option..

43 Adding North Arrows isn t as straightforward as you might think. To add one you need to go to Layout Add Image. Under Item Properties, find the Search Directories Option. There are a number of nice North Arrows to choose from.

44 The QGIS Print Composer

45 The QGIS Print Composer Many Options!

46 Resources QGIS - Joining Tables tutorial: QGIS - Building a Map Atlas tutorial: QGIS Topology step-by-step tutorial: QGIS - Grass integration - two options: Using the Processing Plug-in (Spatial data processing framework for QGIS) is easy to use Using the Grass plugin - has more functions but is more difficult to use

47 Resources QGIS Tutorials: Current User Guide: Documents Creating Maps in QGIS: QGIS 2.8 User Guide QGIS 2.8 QGIS Training Manual PyQGIS developer cookbook Tere are TONS of youtube videos out there as well.