Tag Archives: Beginner

Book Review: Learning ArcGIS Geodatabases [eBook]

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Title: Learning ArcGIS Geodatabases
Author: Hussein Nasser
Publisher: Packt Publishing
Year: 2014
Aimed at: ArcGIS – beginner to advanced
Purchased from: www.packtpub.com

Learning ArcGIS Geodatabases

After using MapInfo for four years my familiarity with ArcGIS severely declined. The last time I utilised ArcGIS in employment shapefiles were predominantly used but I knew geodatabases were the way forward. If they were going to play a big part in future employment it made sense to get more intimate with them and learn their inner secrets. This compact eBook seemed like a good place to start…

The first chapter is short and sweet and delivered at a beginner’s level with nice point to point walkthroughs and screenshots to make sure you are following correctly. You are briefed on how to design, author, and edit a geodatabase. The design process involves designing the schema and specifying the field names, data types, and the geometry types for the feature class you wish to create. This logical design is then implemented as a physical schema within the file geodatabase. Finally, we add data to the geodatabase through the use of editing tools in ArcGIS and assign attribute data for each feature created. Very simple stuff so far that provides a foundation for getting set-up for the rest of the book.

The second chapter is a lot bulkier and builds upon the first. The initial task in Chapter 2 is to add new attributes to the feature classes followed by altering field properties to suit requirements. You are introduced to domains, designed to help you reduce errors while creating features and preserve data integrity, and subtypes. We are shown how to create a relationship class so we can link one feature in a spatial dataset to multiple records in a non-spatial table stored in the geodatabase as an object table. The next venture in this chapter takes a quick look at converting labels to an annotation class before ending with importing other datasets such as shapefiles, CAD files, and coverage classes and integrating them into the geodatabase as a single point of spatial reference for a project.

Chapter 3 looks at improving the rough and ready design of the geodatabase through entity-relationship modelling, which is a logical diagram of the geodatabase that shows relationships in the data. It is used to reduce the cost of future maintenance. Most of the steps from the first two chapters are revisited as we are taken through creating a geodatabase based on the new entity relationship model. The new model reduces the number of feature classes and improves efficiency through domains, subtypes and relationship classes. Besides a new train of thought on modelling a geodatabase for simplicity the only new technical feature presented in the chapter is enabling attachments in the feature class. It is important to test the design of the geodatabases through ArcGIS, testing includes adding a feature, making use of the domains and subtypes, and test the attachment capabilities to make sure that your set-up works as it should.

Chapter 4 begins with the premise of optimizing geodatabases through tuning tools. Three key optimizing features are discussed; indexing, compressing, and compacting. The simplicity of the first three chapters dwindles and we enter a more intermediate realm. For indexing, how to enable attribute indexing and spatial indexing in ArcGIS is discussed along with using indexes effectively. Many of you may have heard about database indexing before, but the concept of compression and compacting in a database may be foreign. These concepts are explored and their effective implementation explained.

The first part of the fifth chapter steps away from the GUI of ArcGIS for Desktop and ArcCatalog and switches to Python programming for geodatabase tasks. Although laden with simplicity, if you have absolutely no experience with programming or knowledge of the general concepts well then this chapter may be beyond your comprehension, but I would suggest performing the walkthroughs as it might give you an appetite for future programming endeavours. We are shown how to programmatically create a file geodatabase, add fields, delete fields, and make a copy of a feature class to another feature class. All this is achieved through Python using the arcpy module. Although aimed at highlighting the integration of programming with geodatabase creation and maintenance the author also highlights how programming and automation improves efficiency.

The second part of the chapter provides an alternative to using programming for geoprocessing automation in the form of the Model Builder. The walkthrough shows us how to use the Model Builder to build a simple model to create a file geodatabase and add a feature class to it.

The final chapter steps up a level from file geodatabases to enterprise geodatabases.

“An enterprise geodatabase is a geodatabase that is built and configured on top of a powerful relational database management system. These geodatabases are designed for multiple users operating simultaneously over a network.”

The author walks us through installing Microsoft SQL Server Express and lists some of the benefits of employing an enterprise geodatabase system. Once the installation is complete the next step is to connect to the database from a local and remote machine. Once connections are established and tested an enterprise geodatabase can be created to and its functionality utilised. You can also migrate a file geodatabase to and enterprise geodatabase. The last part of Chapter 6 shows how privileges can be used to grant users access to data that you have created or deny them access. Security is an integral part of database management.

Overall Verdict: for such a compact eBook (158 pages) it packs a decent amount of information that provides good value for money, and it also introduces other learning ventures that come part and parcel with databases in general and therefore geodatabases. Many of the sections could be expanded based on their material but the pagination would then increase into many hundreds (and more) and beyond the scope of this book. The author, Hussein Nasser, does a great job with limiting the focus to the workings of geodatabases and not veering off on any unnecessary tangents. I would recommend using complimentary material to bolster your knowledge with regards to many of the aspects such as entity-relationship diagrams, indexing (both spatial and non-spatial), Python programming, the Model Builder, enterprise geodatabases and anything else you found interesting that was only briefly touched on. Overall the text is a foundation for easing your way into geodatabase life, especially if shapefiles are still the centre of you GIS data universe.

Book Review: The ESRI Guide to GIS Analysis Vol. 1: Geographic Patterns & Relationships

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Title: The ESRI Guide to GIS Analysis Vol. 1: Geographic Patterns & Relationships
Author: Andy Mitchell
Publisher: ESRI Press
Year: 1999
Aimed at: GIS/Analysts/Map Designers – beginner
Purchased from: www.wordery.com

GIS Analysis Vol 1

This textbook is a companion text for GIS Tutorial 2: Spatial Analysis Workbook (for ArcGIS 10.3.x) where you can match up the chapters in each book. Although not a necessity, I would recommend using both texts in tandem to apply the theory and methods discussed with practical tutorials and walkthroughs using ArcGIS.

The title of this book might lead you to believe that ArcGIS will feature heavily throughout the text but Michael F. Goodchild sets this straight in the Preface by stating that he applauds ESRI for backing this book even though it isn’t Arc eccentric. The author, Andy Mitchell, presents the material as generic GIS such that most GIS software packages should be able to utilise the techniques discussed.

Chapter 1 is a short introduction to what GIS analysis is, understanding the representation of geographic features in a GIS, and the common attributes associated with geographic features that allow for analysis. The wording is simplistic in nature and easy to follow, and acts as a good entrance to the rest of the book.

The second chapter begins to delve into the realm of visual analysis, using your brain to to discern patterns for a better understanding of the data and the area that you are mapping. Several real-life mapped examples are displayed to show how ‘mapping where things are’ aids in more focused decision making. The chapter steps through; deciding what to map, preparing your data, and making your map, with comparison figures to show you why you might perform such tasks.

Why map the most and least? Because mapping features based on quantities adds an additional level of information beyond simply mapping the locations of the features and this notion is made clear from providing some real-life examples in Chapter 3. The author then takes us down a path to understanding quantities and the importance of knowing the type of quantities that you are mapping, and this naturally leads onto the next topic of classification, why use classes? and choosing an appropriate classification method/scheme for the purpose of your data. It is important to understand how classification methods such as Natural Breaks (Jenk’s), Quantile, Equal Interval, and Standard Deviation classify your data and having a general guideline on choosing the appropriate method.

A great recurring aspect in this book is that every chapter begins with a question and Chapter 4’s is ‘Why Map Density?’ and then proceeds to answer the question and the methods available for mapping in a GIS. This chapter discusses density for defined areas, dot density mapping, and density surfaces, what the GIS does to create them and the results of the output.

The fifth chapter takes a look at mapping what’s inside an area, discusses why you would want to map inside an area?, and some analysis and results that can be derived from such. Do you need to map a single area to find what’s happening inside or multiple areas to analyse what’s happening inside each for comparison purposes? Methods are explained along with how the GIS performs these for analysis. You might want to find out if a certain feature is within an area, a list of all features inside an area and a count of each, or the sum of a designated land type area within a boundary for examples. Summaries and statistics can also be generated from what is found inside an area boundary.

Having assessed some simple techniques for mapping what’s inside an area, the next chapter casts it’s attention towards finding what’s nearby. People often think of nearness in straight lines or along transport networks, but GIS is also useful for travel cost analysis giving weight to different land use or soil types for example when considering the path for a pipeline. Nearness by straight-line distance, distance/cost over a network, and cost over a geographic surface are discussed in detail. At this point we are venturing into understanding some of the concepts behind Network Analysis.

The last chapter looks at mapping change with regards to change over time for time pattern analysis. Three ways of mapping change are presented; creating a time series, creating a tracking map, and measuring change, along with the considerations required when creating each type for change in discrete features, events, summarized areas, and continuous categories and values.

Following the last chapter there are some recommendations for some further reading.

Overall Verdict: The perfect companion for a GIS student embarking on their geospatial educational quest. The theory behind GIS is essential for accurate analysis and troubleshooting. This book is an easy read with a plethora of figures and maps utilised in real-life situations found in each chapter to aid in the experience. Although getting closer to being two decades old this text stands the test of time and acts as a solid base for a foundation in simple analysis using a GIS to find patterns and relationships.

The only shortcoming of a text of this nature is that you cannot see how methods and techniques discussed are performed in a GIS. This is where the companion text GIS Tutorial 2: Spatial Analysis Workbook (for ArcGIS 10.3.x) comes in and aids in providing walkthroughs to further enhance your understanding of the underlying theory.

Next: see The ESRI Guide to GIS Analysis Volume 2: Spatial Measurements & Statistics

Book Review: Learning QGIS by Anita Graser [eBook]

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Title: Learning QGIS (Second Edition)
Author: Anita Graser
Publisher: Packt Publishing
Year: 2014
Aimed at: QGIS – beginner, GIS/Python – knowledgeable
Purchased from: www.packtpub.com

Learning QGISMy New Years resolution is to upgrade skills and software knowledge instead of sitting in front of a TV for hours on end (we’ll see how long this lasts). About six years ago I installed QGIS on my laptop, never used it, removed it, reinstalled it, never used it, removed it and this cycle has continued for each year. I am putting a stop this vicious cycle as of now and aim to become proficient with this well renowned piece of open source software, with my main goal to incorporate Python for automation and develop some plugins. I will become familiar with the software before making the leap to Python.

There’s only so much you can fit into 125 pages and while this book is packed with information on the capabilities of QGIS it certainly leaves you wanting more. I think this is a good problem as it drives you to do your own research and play around with what’s on offer in QGIS based on your own interest.

The book starts off by guiding you through the installation process and then provides a brief description of the interface and available toolbars.

In Chapter 2 we begin to add spatial data (vector and raster) to the map. The link provided to download the sample data didn’t stand the test of time (a year) but was easy to locate with an internet search. We are also introduced to georeferencing, loading data from databases and accessing data from OGC web services, ending without a brief styling tutorial.

The main part of the third chapter walks us through creating and editing geometries and attribute data. We also encounter using the measurements tools, the field calculator, reprojecting and converting files, and joining tabular data.

Chapter 4 presents Spatial Analysis; clipping a raster, terrain analysis, raster calculator, vector to raster and raster to vector conversions, heatmaps, vector geoprocessing (proximity analysis), raster sampling at point locations, density with hexagonal grids, calculate are shares within a region. There is a lot of information in this chapter, without nearly being exhaustive, that emphasizes the analytical capabilities of QGIS.

“Creating Great Maps” is the title of the fifth chapter. Did it hold up to this title? In short, yes, but you are not walked through step by step with someone holding your hand, you are presented with visualization and styling techniques to help you create your own masterpiece. A whole book could be dedicated to this topic.

The final chapter jumps straight into “Extending QGIS with Python” and is certainly not for those just beginning programming with Python. Lines of code are given with a general overview of what’s happening and knowledge of syntax and the API is required here. As a newbie to the QGIS API I found this chapter a bit daunting but time, effort and the will to learn more is a challenge that I accept. The chapter and indeed the book concludes with an example of a processing script and developing and implementing a plugin.

QGIS Python Console

QGIS Python Console

One thing this book has thought me is that QGIS is highly customizable to user preferences and visualizations. My next step is to gain more familiarity with QGIS through available text books and online tutorials before heading down the customization path with Python.

Overall Verdict: Although it was difficult to follow some of the workflows exactly, and this is perhaps because it is more informative than tutorial, I felt this was a good intro to QGIS, what the software has to offer, how to navigate the GUI and the possibilities of extending QGIS with Python. The book cost me a whopping €5.63 from a sale on the Packt Publishing website. This book is packed with info and provided a solid beginning on my quest to QGIS stardom. I am already wondering why it took my so long to break out of that repetitive cycle.

Book Review: Python Scripting for ArcGIS by Paul A. Zandbergen

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Title: Python Scripting for ArcGIS
Author: Paul A. Zanbergen
Publisher: ESRI Press
Year: 2013
Aimed at: Python/ArcPy – beginners, ArcGIS – knowledgeable
Purchased from: www.bookdepository.com

Python Scripting for ArcGIS

This book is a fantastic stepping stone for beginners into the enchanted world of ArcPy. ArcPy is a Python site package that provides access to the extensive set of geoprocessing tools available in ArcGIS. Besides enabling programmatic geospatial analysis ArcPy modules also facilitate data management, data conversion and map document management.

I think a quote from the Preface pages of this book aptly sums up what the book is all about.

“a little bit of code goes a long way.”

As an introductory text your eyes will be opened to how small snippets of code can run geoprocessing tools that can form the basis for extensive geospatial analysis. You won’t find in-depth spatial analysis or data management techniques but you will find an easy to read, easy to follow informative text book that provides the theory behind using Python/ArcPy and will act as a reference to the capabilities of ArcPy.

Before purchasing this book I read a number of reviews. While an overwhelming majority applauded the book there where a few who complained about the basic introduction to Python provided. Even though there is a chapter dedicated to creating Python functions and classes one review that sticks out in my mind wanted in-depth object orientated programming for GIS Python which to me is miles beyond the scope of this book. The author does a great job of providing a primer to the Python language but this is not what this book is about. There are a myriad of Python text books for beginners and also online tutorials out there and I would certainly recommend making use of these and getting comfortable with the general syntax, data structures and data types before diving head first into using Python for geospatial activities.

I bought this book because I wanted a foundation for ArcPy that I could build upon. While progressing through the text I was constantly looking to the ArcGIS Resources pages for more information about geoprocessing tools encountered and the syntax required to implement them programmatically. I would recommend using this book in tandem with the Resource pages for the ultimate beginner experience. The book is extremely informative for a beginner’s text but it will be your genuine interest in the material that will take you well beyond what’s on offer here.

The book and topics are well designed with each chapter building upon the previous. The first part introduces the Python language, development environments (PythonWIn and the Interactive Python WIndow in ArcMap), and the basics of geoprocessing. Part two is where you begin your ArcPy experience, writing scripts and learning about ArcPy modules and their capabilities. Part three introduces some specialized tasks such as automating ArcMap workflows through map scripting and error handling is also discussed. Part four provides an introduction to creating your own custom tool.

Some of the more interesting materials I found covered in this book were; working with the mapping module for automating map document tasks, accessing and manipulating data with cursors and the data access module, working with geometries and rasters, and creating custom tools. These will provide the springboard for you to dive into more advanced scripting.

Overall Verdict: The book was a great investment (c. €60). It would be hard to find a better way to introduce yourself to ArcPy. It won’t teach you everything you need to know to build applicable scripts but provides an invaluable foundation. Highly recommended for beginners.