Environmental QGIS Training - GIS 101 (Prerequisite)

hi my name is Chris Roach and I'm manager and GIS specialist acai resources as part of our environmental hugest training I'll have the pleasure of walking you through an introduction to geographic information systems what we call GIS 101 so let's get started GIS stands for geographic information systems and involves taking layers of information and overlaying them to help generate new insights and knowledge about a particular place in our world if you haven't used a GIS before you might be surprised to hear that in fact you have anytime you whip out your phone to find directions to a shop book an uber or have a look at the weather you are either indirectly using or benefiting from a GIS application mapping technology is so embedded in our daily lives and the services we depend on that we often don't realize and take it for granted so what are some examples it could be a website that shows you campsites and trails in your area it could be a system that helps ambulances reach their patients in the shortest possible time or an app that helps volunteers gather information about rare plants and animals maybe it's tools that help planners envisage the future of our cities or farmers to efficiently manage their crops so a GIS can take the form of a desktop mobile or web application or all of the above the type of GIS training this training course will focus on is on the desktop side desktop GIS software is used by scientists planners engineers to bring different themes of information together to visualize and help them make more informed decisions a healthy GIS is in fact not just made up of the software alone it's also a combination of skilled people well provisioned Hardware reliable data and operating standards the computer on which the software is installed needs to be powerful enough the layers of information need to be up-to-date and of a good quality and the people using it need to have the right skills to operate the software nowadays there are numerous desktop GIS software products that come under the banners of either commercial off-the-shelf or cots or free and open-source traditional proprietary GIS products offer a lot of functionality but they do cost thousands of dollars to unlock it over the years altruistic developers have opened up software and so that everyone can use it and in recent times those open-source products rival their costed counterparts for functionality and ease of use here at Gaia Resources we believe in a holistic approach to clients in their projects therefore the majority of the time we encourage the use of the free and open source variety such as QGIS which stands for quantum GIS huges has come and leaps and bounds over the past decade and does not look like stopping anytime soon the QGIS community have really created a fantastic piece of software with the added bonus of being free and open source it becomes that much more powerful due to the community contributions to the codebase and these wonderful things called plugins you can do just about anything on kuja's that would cost tens of thousands of dollars to do on other GIS products on the market so the message here is that if you're starting out with GIS you don't need a big bag of cash to make inroads a geographic information system overlays layers of information called spatial data these layers each represent a theme one layer could represent rivers and these could overlay buildings and satellite imagery in industries speak there are two fundamentally different types of spatial data called vector and raster let's have a look at both of them vector layers consist of points lines or areas and can describe anything from legs to roads to property boundaries and fauna habitats points contain coordinates of where each location sits on the Earth's surface lines are a series of points join together and represent the length of something areas also called polygons are a series of lines that are connected at the start and end point creating a closed boundary and representing the area of something by overlaying these letters we can ask the GIS important questions such as how many disease points are there per local government area how far do I have to drive to get to landowners property or maybe its what species are concentrated or answer in wetlands in the last year vector data usually includes attributes which are a text or numerical elements associated with each feature and starred as fields in a table these tables can be used to sort and query vectors by querying vector data one can quickly select a subset based on a range of values and work with those separately or color or layer according to the unique values in a field for example you may wish to sort a town dataset select only those that are above 10,000 in population and then give those a different color to the ones that are below 10,000 in population one of the most powerful functions in a GIS is the ability to select features using the spatial relationship between them this is called a spatial query for example you may wish to know how many parks are contained within a council area first you could use a query to select the council area based on its name then a spatial query to select all the parks that fall inside that council one of the most popular vector formats to use are called ESRI shapefiles they are the basic building blocks for storing geometric location and attribute information of geographical features which can be represented as I said as points lines and polygons shape files comprise up to 15 individual files with the most common being SHP which stores the future' geometry dot DB F which stores the features attributes dot prj which stores information about the data's projection and a number of other different index spatial index files and file types like SPN SPX and XML when using or transferring show files a GIS analyst needs to be aware that all of the extensions with the same name need to go with it otherwise the data won't work then look shape files are not the only vector format out there by any means some of the other common formats include map info tab files and a number of CAD formats like DXF DWG and dgn raster layers can represent elevation satellite imagery geo reference maps temperature or modeling results raster layers are grids where each small cell has a value for a common variable like depth to groundwater each cell in a raster layer has the same sighs and these cells are usually square unlike vector less raster layers don't include a database record for each cell instead each one contains a value for a single variable in cases where there are multiple variables that need to be overlaid in the same area raster layers use the concept of one band for each one let's imagine looking down from an aeroplane and snapping a photograph below you then dividing that photograph into a grid of 1000 by 1000 photographs from your digital camera or phone are in fact also examples of raster data the cell values in those outputs represent the red green and blue values of that beautiful sunset that you took apart from the obvious value of a backdrop for a map a number of questions can be answered by overlaying Leigha and analyzing raster layers such as how much native vegetation and habitat is being cleared each year or how many deep - bores need to be to reach an aquifer or maybe it's about can we predict the spread of dieback disease over time at this point you're probably wondering which type of data should I use vector or raster that both have their advantages but chances are you will want to use both types raster layers are great as backdrops for a map particularly at a regional scale but the power of this type of data is when you want to do quantitative analysis of things that are not discrete or look at change over time this could be monitoring the change of vegetation or land use over time or monitoring sea surface temperatures and the relationship between this and mammal sightings perhaps it's about looking at rainfall over the last 10 years and the impact of a drawing climate on salinity and tree health a distinct advantage of raster layers is the ability to perform map algebra that is using mathematical functions on individual cell values or between the same cell on two overlapping raster layers vector layers with their points lines and areas can be a more aesthetically pleasing representation of some spatial data than raster layers discrete boundaries like electorates or pedestrian properties or pipelines for instance or fixed points like Wells and bus stops are better represented through a vector of data vector layers really come into their own with the ability to associate attributes or a database of text in numerical fields against the features on the map these attribute values can be queried to quickly select manage and map subsets of vector data for example you may want to have a data set of rare flora occurrences across a region and need a map to show only orchid species found in the last five years if each feature records a species name than a date of observation the standard query tools in a GIS can be used to quickly select and only show these on your map with a different color for each species topology or the special relationship between features is also a major advantage of vector layers a GIS can be used to understand the number of features that fall inside outside intersecting or nearby a particular place for example you may need to know how many landowners have their properties adjacent to a river the resulting data set attributes could then tell you who those adjacent landowners are and how to get in contact with them for a GIS analyst topology is also about looking at the quality of spatial data by this I mean in order to do analyses you need to look at whether the data you are using has things like gaps and overlaps and by cleaning this information you're ensuring that you will get accurate results GIS software like QGIS contains a number of topological tools that can help you diagnose and correct these sorts of errors in your data a GIS and any map should have a scale value clearly stated so that the person looking at the information can understand how the measurement or area on the map relates to the corresponding distance or area in the real world a map of your country depending on the country will likely have a very big value for the scale like 1 to 25 million whereas a map of your town or your project area will have much smaller scale value in cartography or not making within GIS there are too confusing terms relating to scale that you may encounter a large scale map is one that has a low scale ratio like one to four thousand and shows objects on the ground as relatively large that is compared to a small scale map where the scale ratio is high like 1 to 24 million and shows objects is relatively small a large scale map could show your fieldwork around a river or coastline whereas a small scale map might show features across an entire country a coordinate reference system is an integral part of spatial data because it determines where data is located in the spatial world it is the framework on which a GIS can compare one set of spatial data like soil landscape zones to another such as vegetation quadrats creating or amending data in the wrong CRS can cause it to be corrupted inaccurate or just plain nonsensical in correctly defined CRS systems are one of the main factors that lead to corrupted information and analysis results spatial data can be represented in Geographic or projected coordinate systems a geographic system is based on approximating the earth as a sphere and represents coordinates as latitudes and longitude whereas a projected system attempts to project parts of the Earth's surface onto a flat plane and coordinates for projected systems come in the form of eastings and northings an analyst should choose to work in different projected coordinate systems depending on whether they are calculating areas accurately or calculating distances accurately or just wanting a visually accurate display there are many projected CRS is out there and each one tries to get one of these aspects correct to show spatial data correctly on a map it must have coordinates and the correct coordinate system defined so for this location on the ground the location values or coordinates are very different when referenced in different coordinate reference systems let's take a location here in Western Australia the coordinates on the left hand side are in Geographic datum of Australia a geographic CRS and we have a latitude and longitude well the same location on the right hand side has its coordinates in the map grid of Australia zone 50 which is a projected CRS if you have a G da point and try and map it in an mga zone 50 projection your point will end up in an unexpected location this is because a map is expecting a six digit easting and seven digit northern and what it's getting is a three digit and two digit values so why is this important well if your environmental analysis and conclusions are based on the area of something like weed control area versus money spent then you need your calculations to be accurate in this case all of the input layer should be in the same CRS and projected rather than Geographic that gives you an accurate area if you are more interested in overlaying layers and interpreting things visually then there's an on-the-fly option in huges that is much more efficient than going and converting your data layers into the same CRS in a healthy GIS layers will have corresponding documents or descriptions of the data called metadata so this is where they tell you about the data set who created it why when was it published what does it contain is it complete who should I speak to for more information metadata can be very important because it helps us to understand if the data is suitable for our particular mapping or GIS analysis tasks put another way it helps to avoid inappropriate use of the data where it's not a lot obvious from looking at the data itself so for example using layers that are out of date is a common trap where you're attempting to map the current state of something let's take fire scars friends it's fine to use a 2010 fire scar layer if you want to show bushfire extents prior to that year but it's a bit misleading if you're wanting to show us what's going on in this current year metadata can be useful in this sense to understand the dates of that data relates to and the right person to contact to go and get the more current stuff metadata can take the form of a simple document like a readme text file with some very basic information about the data it accompanies or a whole range of information could be written into a word document or a PDF metadata often takes the form of an XML formatted file which is a bit cryptic but it's used by a GIS software application to display there are even ISO standards relating to metadata which are designed to bring consistency and ensure quality in the way that we describe spatial information the most notable of these that you might encounter is iso:191 1:5 this short video has given those beginning with GIS software a taste of what it can do and how it can be a valuable tool set for a range of environmental applications look it only scratches the surface of what is a massive discipline crossing a wide range of industries there are numerous resources that you can go to for more information there is the wiki GIS comm which contains informative articles about GIS concepts glossary new technologies products and organizations and there are freebie GIS beginner courses out there from OpenCourseWare and massive open online courses and if you're interested in finding free government spatial data particularly in Australia I'd encourage you to check out these two tato portals and of course if we've really ignited a fire in your soul and you want to pursue GIS as a profession or a qualification to supplement your current career there are university degrees and graduate diplomas out there many universities offer dedicated GIS degrees under the banner of spatial Sciences Geoscience or geography and some offer graduate diplomas equiping scientists or planners with the technical skills they need to leverage GIS in their profession so I hope you've enjoyed this video and can get started thanks very much

Channel: Gaia Resources

Views: 5,426

Keywords: QGIS, GIS, environment, spatial, NRM, natural resource management, QGIS training, GIS training

Id: 6Q2SpYeLWTU

Length: 18min 24sec (1104 seconds)

Published: Mon Apr 02 2018