3.1.1.  跟我做：查看图层属性（Follow Along: Viewing Layer Attributes）

首先要明确的是，我们即将操作的数据，不仅代表了他们在空间中的位置，还包含了他们是什么的各种属性（It’s important to know that the data you will be working with does not only represent where objects are in space, but also tells you what those objects are.）

接前面的练习，在你的地图中已经加载了道路层。你也可以看到现在只是展示了道路的位置。（From the previous exercise, you should have the roads layer loaded in your map. What you can see right now is merely the position of the roads.）

要看到所有的形状要素属性，先在图层列表面板中选中该图层。（To see all the data available to you, with the roads layer selected in the Layers panel:）

• 点击这个按钮：（Click on this button: ）

你会看到一个关于道路图层有更多信息的数据表。这些额外的数据被称为属性数据。在地图中能看到的那些线条是空间数据。(It will show you a table with more data about the roads layer. This extra data is called attribute data. The lines that you can see on your map represent where the roads go; this is the spatial data.)

这是GIS中很常见的一些定义，比较重要，请记住它们。（These definitions are commonly used in GIS, so it’s essential to remember them!）

• （现在，可以关闭属性表了）You may now close the attribute table.

矢量数据在坐标平面上以点、 线和多边形的形式来表现图形要素。它通常用于存储离散的图形要素，如道路和城市街区等。（Vector data represents features in terms of points, lines and polygons on a coordinate plane. It is usually used to store discrete features, like roads and city blocks.）

3.1.2.  跟我做：从shp加载矢量数据（Follow Along: Loading Vector Data From Shapefiles）

Shapefile 是一种可以将 GIS 数据存储在一组关联的多个文件中的特定文件格式【译者注：每个shp文件都是由多个文件组成的】。这些文件有共同的文件名，但是有各自的不同的扩展名（文件类型）。Shapefiles 可以很方便的来回发送，并且大多数 GIS 软件都可以阅读它们。（The Shapefile is a specific file format that allows you to store GIS data in an associated group of files. Each layer consists of several files with the same name, but different file types. Shapefiles are easy to send back and forth, and most GIS software can read them.）

参考上一节所讲的如何加载矢量图层的方法，（Refer back to the introductory exercise in the previous section for instructions on how to add vector layers.）

把以下数据集加载到地图中：（Load the data sets into your map following the same method:）

• “places”
• “water”
• “rivers”
• “buildings”

3.1.3.  跟我做：从数据库中加载矢量数据（Follow Along: Loading Vector Data From a Database）

数据库能够让你在一个文件中存储了大量的相关联的数据。您可能已经对类似 Microsoft Access这样的 数据库管理系统 (DBMS)有所了解。GIS应用程序也可以使用的数据库。具有地理信息系统特性的 DBMS (比如 PostGIS) 会有额外的功能，因为他们需要处理空间数据。（Databases allow you to store a large volume of associated data in one file. You may already be familiar with a database management system (DBMS) such as Microsoft Access. GIS applications can also make use of databases. GIS-specific DBMSes (such as PostGIS) have extra functions, because they need to handle spatial data.）

• 点击这个按钮：（Click on this icon: ）

（如果你找不到该按钮，检查 图层管理 工具栏是否被打开）(If you’re sure you can’t see it at all, check that the Manage Layers toolbar is enabled.)

将打开一个新的对话框。在这个对话框中：（It will give you a new dialog. In this dialog:）

• 点击新建 按钮。（Click the New button.）
• 在之前的路径下，找到landuse.sqlite这个文件。选中它，并打开。（In the same folder as the other data, you should find the file landuse.sqlite. Select it and click Open.）

你会看到在刚刚的那个对话框里面，三个按钮的上面已经填写上了 “land_use.db@…”这样的文字，@后面跟着的是你计算机上数据库文件的路径。You will now see the first dialog again. Notice that the dropdown select above the three buttons now reads “land_use.db@…”, followed by the path of the database file on your computer.

• 点击 连接 按钮。你会发现在原来的空白区域多出了一条内容：（.Click the Connect button. You should see this in the previously empty box:）

• 点击 landuse 图层来选中它，然后点击 添加按钮。（Click on the landuse layer to select it, then click Add）

3.1.4. 跟我做：给图层排序（Follow Along: Reordering the Layers）

在图层列表中的图层会按照一定的顺序进行绘制。在列表顶部的图层最先绘制，列表底部的图层最后绘制。通过更改它们在列表中排列的顺序，可以更改绘制它们的顺序。（The layers in your Layers list are drawn on the map in a certain order. The layer at the bottom of the list is drawn first, and the layer at the top is drawn last. By changing the order that they are shown on the list, you can change the order they are drawn in.）

当前已经加载的图层可能绘制的顺序是不合逻辑的。比如道路可能是完全被挡住的，因为有别的图层在它上面。The order in which the layers have been loaded into the map is probably not logical at this stage. It’s possible that the road layer is completely hidden because other layers are on top of it.

比如说这种图层顺序（landuse就会把road挡住）：（For example, this layer order..）.

通过以下措施来解决这个问题：（To resolve this problem:）

• 按住并拖拽某个图层（来调整顺序）（Click and drag on a layer in the Layers list.）
• 将各个图层按以下顺序排序：（Reorder them to look like this:）

现在地图变得更有意义了，道路和建筑物出现在土地使用区域的上面。（You’ll see that the map now makes more sense visually, with roads and buildings appearing above the land use regions.）

3.1.5.小结（ In Conclusion）

现在你已经学会了添加不同来源的矢量图层。（Now you’ve added all the layers you need from several different sources.）

3.1.6. What’s Next?

使用加载图层时随机生成的样式和颜色可能会导致你的地图不太好识别。所以我们要自己来设定他们的颜色和符号，这就是下一节课的内容。（Using the random palette automatically assigned when loading the layers, your current map is probably not easy to read. It would be preferable to assign your own choice of colors and symbols. This is what you’ll learn to do in the next lesson.）

2.2.1.  跟我做：准备一张地图（Follow Along: Prepare a map）

• 打开QGIS，你会看到一个新建的空白地图。（Open QGIS. You will have a new, blank map.）
• 找到添加矢量图层按钮。（Look for the Add Vector Layer button: ）
• 点击它打开以下对话框：（Click on it to open the following dialog:）

• 点击浏览按钮，导航到 exercise_data/epsg4326/roads.shp 这个文件（在示例数据集的目录下）。选中该文件后，点击打开。你会看到刚刚那个对话框，但是文件路径填写在数据源的文本框里了。继续点击打开。你指定的数据将被加载到窗口中。（Click on the Browse button and navigate to the file exercise_data/epsg4326/roads.shp (in your course directory). With this file selected, click Open. You will see the original dialog, but with the file path filled in. Click Open here as well. The data you specified will now load.）

恭喜你！你现在完成了一个基本的地图。现在让我们来保存一下当前的工作。（Congratulations! You now have a basic map. Now would be a good time to save your work.）

• 点击另存为按钮：。（Click on the Save As button: ）
• 将地图保存在 exercise_data/ 路径下，并取名为 basic_map.qgs 。（Save the map under exercise_data/ and call it basic_map.qgs.）

检查结果（通过发表评论，检查你是否做对了）：

——————————————————-

你会看到许多的线条，各式各样的道路。这些线条都来自你刚刚加载的图层。（You should see a lot of lines, symbolizing roads. All these lines are in the vector layer that you just loaded to create a basic map.）

——————————————————-

2.2.2. 小结（In Conclusion）

你已经学会了如何添加一个图层，并创建一个基本的地图！（You’ve learned how to add a layer and create a basic map!）

2.2.3. 接下来学什么？（What’s Next?）

现在你已经知道了如何使用添加矢量图层按钮，但是所有其他的按钮是干啥的呢?这个操作界面是如何工作的呢?在我们学习更多内容之前，让我们先来好好看看 QGIS 操作界面的总体布局。这就是下一课的主题。（Now you’re familiar with the function of the Add Vector Layer button, but what about all the others? How does this interface work? Before we go on with the more involved stuff, let’s first take a good look at the general layout of the QGIS interface. This is the topic of the next lesson.）

2.1.1. 如何使用本教程（How to use this tutorial）

任何 像我这样的文字  表示可以点击的链接。（Any text that looks like this refers to something on the screen that you can click on.）

任何 像 ‣ 我这样 ‣的文字 表示菜单或操作步骤（Text that looks ‣ like ‣ this directs you through menus.）

像我这样的文字表示你要输入的内容，比如一句命令，路径或文件名。（This kind of text refers to something you can type, such as a command, path, or file name.）

2.1.2. 课程目标（Tiered course objectives）

本课程迎合不同经验水平的用户需求分为三个级别。根据你自己的实际情况，在你可以有不同的课程训练内容和成果。每个级别所包含的信息和内容都对下一个级别至关重要，所以，请确保完成你所处的级别和低于你级别的所有练习。（This course caters to different user experience levels. Depending on which category you consider yourself to be in, you can expect a different set of course outcomes. Each category contains information that is essential for the next one, so it’s important to do all exercises that are at or below your level of experience.）

2.1.3. 为什么选择QGIS？（Why QGIS?）

随着信息与空间之间的关联越来越密切，目前并不缺乏能够履行部分或全部常用 GIS 功能的软件。那为什么要使用 QGIS而不是其他的GIS软件呢？（As information becomes increasingly spatially aware, there is no shortage of tools able to fulfill some or all commonly used GIS functions. Why should anyone be using QGIS over some other GIS software package?）

这里只是一些原因：（Here are only some of the reasons:）

• 它是免费的。安装和使用 QGIS 程序金钱成本为零。无初始费，没有年度订阅的费用，什么都没有。（It’s free, as in lunch. Installing and using the QGIS program costs you a grand total of zero money. No initial fee, no recurring fee, nothing.）
• 它是自由的。如果您需要在 QGIS 额外功能，除了傻等下一个软件版本包含此功能外，你还可以做更多：可以赞助开发某一项功能或直接自己开发它（前提是你会编程哦）。（It’s free, as in liberty. If you need extra functionality in QGIS, you can do more than just hope it will be included in the next release. You can sponsor the development of a feature, or add it yourself if you are familiar with programming.）
• 它正在不断发展的。因为任何人都可以添加新功能和改进现有的 QGIS ，所以它从不停滞。新的工具和插件可以因为你的需要而被快速开发出来。（It’s constantly developing. Because anyone can add new features and improve on existing ones, QGIS never stagnates. The development of a new tool can happen as quickly as you need it to.）
• 它有广泛的帮助文件和文档。如果你遇到任何问题，你可以阅读官方文档、求助于其他QGIS 用户甚至是开发人员。（Extensive help and documentation is available. If you’re stuck with anything, you can turn to the extensive documentation, your fellow QGIS users, or even the developers.）
• 它是跨平台的。QGIS可以安装在 Mac、 Windows 和 Linux 上。（Cross-platform. QGIS can be installed on MacOS, Windows and Linux.）

现在，你知道为什么要使用 QGIS了，接下来我们会告诉你如何使用。第一节课将指导你创建第一个 QGIS 地图。（Now that you know why you want to use QGIS, we can show you how. The first lesson will guide you in creating your first QGIS map.）

1.2.1. 动手试（Try Yourself）

如果你想用你本地的数据集替换默认数据集，可以轻松通过内置的 QGIS 工具来完成。但您选择使用的区域应该很好的同时包含城市和农村地区，包含不同等级的道路、 不同的区域边界 (如自然保护区或农场) 和水域，如小溪和河流等。（If you wish to replace the default data set with localised data for your course, this can easily be done with tools built into QGIS. The region you choose to use should have a good mix of urban and rural areas, containing roads of differing significance, area boundaries (such as nature reserves or farms) and surface water, such as streams and rivers.）

• 打开一个空白的QGIS工程（Open a new QGIS project）
• 在“矢量”下拉菜单下，选择“开放街道地图（OpenStreetMap）“->”下载数据”。你可以进一步的手动输入你想设置的区域坐标，或者你可以通过一个图层来设置边界。（In the Vector menu dropdown, select OpenStreetMap -> Download Data. You can then manually enter the co-ordinates of the region you wish to use, or you can use an existing layer to set the co-ordinates.）
• 选择一个位置来保存输出结果的.osm文件，并点击“确定”：（Choose a location to save the resulting .osm file and click Ok:）

• 你可以通过“添加矢量图层”按钮来打开刚刚的osm文件，在浏览窗口的文件类型中选择“全部文件”以便能方便找到osm文件。或者你可以直接将osm文件拖拽到QGIS窗口中来打开。（You can then open the .osm file using the Add Vector Layer button. You may need to select All files in the browser window. Alternatively, you can drag and drop the file into the QGIS window.）
• 在弹出的图层选择窗口中，选择除other_relations 和multilinestrings之外的所有图层。（In the dialog which opens, select all the layers, except the other_relations andmultilinestrings layer:）

点击“确定”后会加载四个符合OSM命名协定的图层，通过缩放工具来查看此矢量数据。（This will load four layers into your map which relate to OSM’s naming conventions (you may need to zoom in/out to see the vector data).）

我们需要从这些层中提取有用的数据，将它们重命名并创建相应shp文件：（We need to extract the useful data from these layers, rename them and create corresponding shape files:）

• 首先，双击multipolygons图层来打开图层属性对话框。（First, double-click the multipolygons layer to open the Layer properties dialog.）
• 在通用标签下，点击“查询生成器”来打开查询生成器窗口。（In the General tab, click Query Builder to open the Query builder window.）

我们将提取该图层的下面三个字段：（This layer contains three fields whose data we will need to extract for use throughout the Training Manual:）

• building
• natural (specifically, water，主要指水域)
• landuse

你可以测试你选择的区域会产生什么样的结果。如果您发现“landuse”没有返回任何结果，就可以随时排除该区域，重新选一块。（You can sample the data your region contains in order to see what kind of results your region will yield. If you find that “landuse” returns no results, then feel free to exclude it.）

你需要为每个字段编写筛选器表达式来提取我们所需要的数据。我们将使用“building”字段作为一个例子来说明:（You’ll need to write filter expressions for each field to extract the data we need. We’ll use the “building” field as an example here:）

• 把下面这个表达式输入到文本区域：building != “NULL”   然后点击“测试”来观察本次查询返回了多少条结果。如果返回的结果数很少，你可以打开图层的“属性表”来看一下从OSM获取到了缩少本区域的数据：（Enter the following expression into the text area: building != "NULL" and click Test to see how many results the query will return. If the number of results is small, you may wish to have a look at the layer’s Attribute Table to see what data OSM has returned for your region:）

• 点击“确定”，你会看到不属于建筑物（building）的要素从地图上隐藏掉了。（Click Ok and you’ll see that the layer elements which are not buildings have been removed from the map.）

我们需要将查询结果保存为shp文件，以便用于本次培训课程：（We now need to save the resulting data as a shapefile for you to use during your course:）

• 右键点击multipolygons图层，并选择”另存为“。（Right-click the multipolygons layer and select Save As…）
• 请确认保存文件类型为ESRI shapefile，并将文件保存到你自己的”exercise_data“文件夹下，并将该文件夹放到”epsg4326“的目录下。【译者注：就是放到”/epsg4326/exercise_data/“下面】（Make sure the file type is ESRI Shapefile and save the file in your new exercise_datadirectory, under a directory called “epsg4326”.）
• 保存过程中确保选中”无样式“，我们会再稍后的课程中添加样式。（Make sure No Symbology is selected (we’ll add symbology as part of the course later on).）
• 你也可以选中”将保存后的文件添加到地图“（You can also select Add saved file to map.）

一旦查询出为”building”的数据后，你可以通过在查询生成器中替换原来的表达式为以下表达式来查询”natural“和”landuse“的数据：（Once the buildings layer has been added to the map, you can repeat the process for thenatural and landuse fields using the following expressions:）

• natural: “natural = ‘water’”
• landuse: “landuse != ‘NULL’”

每一份结果数据集都要保存在”/epsg4326/exercise_data/“目录下面，可以将数据集保存为“水域”“土地利用”等名称。（Each resulting data set should be saved in the “epsg4326” directory in your new exercise_datadirectory (i.e. “water”, “landuse”).）

然后应从lines和points图层提取以下字段并保存到相应的目录:（You should then extract and save the following fields from the lines and points layers to their corresponding directories:）

• lines: “highway != ‘NULL’” to roads, and “waterway != ‘NULL’” to rivers
• points: “place != ‘NULL’” to places

当你完成以上提取工作后，你可以将multipolygons, lines和points图层移除。（Once you have finished extracting the above data, you can remove the multipolygons, linesand points layers.）

现在你会得到一幅类似于下面的地图，样式会变得非常不一样，但这并不重要。（You should now have a map which looks something like this (the symbology will certainly be very different, but that is fine):）

重要的是你现在拥有6个类似于上图所示的图层，并且每个图层都含有数据。（The important thing is that you have 6 layers matching those shown above and that all those layers have some data.）

最后一步是从landuse图层创建用于本教程的 spatiallite 文件:（The last step is to create a spatiallite file from the landuse layer for use during the course:）

• 右键点击landuse图层，并选择“另存为”。（Right-click the landuse layer and select Save as…）
• 文件类型选择为 spatiallite 格式，并保存到“/epsg4326/”目录下，文件命名为landuse。（Select SpatialLite as the format and save the file as landuse under the “epsg4326” directory.）
• 点击“确定”。（Click Ok.）
• 删除“landuse.shp”和与它相关的文件（如果有的话）。（Delete the landuse.shp and its related files (if created).）

1.2.2. 动手试–创建SRTM DEM tiff文件（ Try Yourself Create SRTM DEM tiff Files）

在第6单元（创建矢量数据）和第8单元（栅格），你也会用到你选择区域的栅格图像（SRTM DEM）。（For Module 6 (Creating Vector Data) and Module 8 (Rasters), you’ll also need raster images (SRTM DEM) which cover the region you have selected for your course.）

SRTM DEM可以从GIAR-CGI下载。链接为：http://srtm.csi.cgiar.org/。(SRTM DEM can be downloaded from the CGIAR-CGI: http://srtm.csi.cgiar.org/)

你需要将你选择的区域完全覆盖的栅格图像【译者注：如果一块不能完全覆盖，就多下载几块】(You’ll need images which cover the entire region you have chosen to use.)

当你下载了你所需要的文件后（1个或多个），将它们保存在“/epsg4326/exercise_data/raster/SRTM/”目录下（Once you have downloaded the required file(s), they should be saved in the “exercise_data” directory under “raster/SRTM/”.）

在第6单元，第1.2课的时候，会涉及到一个图像，包含三个要求学生需要进行数字化的学校运动场地。因此，你需要对你下载到的SRTM DEM tiff文件进行加工。没有必要必须是学校运动场地，任何三个学校用地类型都可以。（比如不同的校舍，操场和停车场等）（In Module 6, Lesson 1.2 shows close-up images of three school sports fields which students are asked to digitize. You’ll therefore need to reproduce these images using your new SRTM DEM tiff file(s). There is no obligation to use school sports fields: any three school land-use types can be used (e.g. different school buildings, playgrounds or car parks).）

例如，在示例数据中的图像是:（For reference, the images in the example data are:）

1.2.3. 动手试–替换标记（Try Yourself Replace Tokens）

创建您本地化的数据集的最后一步是替换 conf.py 文件中的标记，以便为相应的名称将出现在您本地化版本的培训手册中。（Having created your localised dataset, the final step is to replace the tokens in the conf.py file so that the appropriate names will appear in your localised version of the Training Manual.）

你需要替换的标记有：（The tokens you need to replace are as follows:）

• majorUrbanName: 默认为“Swellendam”， 用你所选区域的名字对其替换。（majorUrbanName: this defaults to “Swellendam”. Replace with the name of the major town in your region.）
• schoolAreaType1: 默认为“athletics field”. 用你所选区域中最大的一种学校区域类型替换。（schoolAreaType1: this defaults to “athletics field”. Replace with the name of the largest school area type in your region.）
• largeLandUseArea: 默认为 “Bontebok National Park”. 用你所选区域中最大的土地利用多边形的名字替换。（largeLandUseArea: this defaults to “Bontebok National Park”. Replace with the name of a large landuse polygon in your region.）
• srtmFileName: 默认为 srtm_41_19.tif. 用你下载的SRTM DEM file名称替换.（srtmFileName: this defaults to srtm_41_19.tif. Replace this with the filename of your SRTM DEM file.）
• localCRS: 默认为 WGS 84 / UTM 34S. 用你所选地区的正确的坐标系进行替换。（localCRS: this defaults to WGS 84 / UTM 34S. You should replace this with the correct CRS for your region.）

原作者：Linfiniti Consulting CC.   翻译：数据地图博客

1.1.2. License（版权）

由Linfiniti Consulting CC.推出的免费QGIS训练手册，是基于来自Linfiniti 的早期手册版本，并遵循Creative Commons Attribution 4.0 International许可，超出该许可的内容如下：（下面列了一些版权方面的信息，略）（The Free Quantum GIS Training Manual by Linfiniti Consulting CC. is based on an earlier version from Linfiniti and is licensed under a Creative Commons Attribution 4.0 International. Permissions beyond the scope of this license may be available at below.）

We have published this QGIS training manual under a liberal license that allows you to freely copy, modify and redistribute this work. A complete copy of the license is available at the end of this document. In simple terms, the usage guidelines are as follows:

• You may not represent this work as your own work, or remove any authorship text or credits from this work.
• You may not redistribute this work under more restrictive permissions than those under which it was provided to you.
• If you add a substantive portion to the work and contribute it back to the project (at least one complete module) you may add your name to the end of the authors list for this document (which will appear on the front page)
• If you contribute minor changes and corrections you may add yourself to the contributors list below.
• If you translate this document in its entirety, you may add your name to the authors list in the form “Translated by Joe Bloggs”.（如果你整体翻译这篇文档，你可以把你的名字以译者的形式添加到作者栏）
• If you sponsor a module or lesson, you may request the author to include an acknowledgement in the beginning of each lesson contributed, e.g.:

• If you are unsure about what you may do under this license, please contact us atoffice@linfiniti.com and we will advise you if what you intend doing is acceptable.
• If you publish this work under a self publishing site such as http://lulu.com we request that you donate the profits to the QGIS project.
• You may not commercialise this work, except with the expressed permission of the authors. To be clear, by commercialisation we mean that you may not sell for profit, create commercial derivative works (e.g. selling content for use as articles in a magazine). The exception to this is if all the profits are given to the QGIS project. You may (and we encourage you to do so) use this work as a text book when conducting training courses, even if the course itself is commercial in nature. In other words, you are welcome to make money by running a training course that uses this work as a text book, but you may not profit off the sales of the book itself – all such profits should be contributed back to QGIS.