外部アプリケーションの設定¶

SAGA: System for Automated Geoscientific Analyses、自動化地球科学的分析システム¶

SAGA algorithms can be run from QGIS if you have SAGA installed in your system and you configure the processing framework properly so it can find SAGA executables. In particular, the SAGA command-line executable is needed to run SAGA algorithms.

If you are running Windows, both the stand-alone installer and the OSGeo4W installer include SAGA along with QGIS, and the path is automatically configured, so there is no need to do anything else.

If you have installed SAGA yourself (remember, you need version 2.1), the path to the SAGA executable must be configured. To do this, open the configuration dialog. In the SAGA block, you will find a setting named SAGA Folder. Enter the path to the folder where SAGA is installed. Close the configuration dialog, and now you are ready to run SAGA algorithms from QGIS.

If you are running Linux, SAGA binaries are not included with SEXTANTE, so you have to download and install the software yourself. Please check the SAGA website for more information. SAGA 2.1 is needed.

In this case, there is no need to configure the path to the SAGA executable, and you will not see those folders. Instead, you must make sure that SAGA is properly installed and its folder is added to the PATH environment variable. Just open a console and type saga_cmd to check that the system can find where the SAGA binaries are located.

Rスクリプトで作成されたR.。¶

R integration in QGIS is different from that of SAGA in that there is not a predefined set of algorithms you can run (except for a few examples). Instead, you should write your scripts and call R commands, much like you would do from R, and in a very similar manner to what we saw in the section dedicated to processing scripts. This section shows you the syntax to use to call those R commands from QGIS and how to use QGIS objects (layers, tables) in them.

The first thing you have to do, as we saw in the case of SAGA, 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.

今一度、これがLinuxでは異なるので、あなたはRフォルダがPATH環境変数に含まれているかをちゃんと確認しなければなりません。もし、お使いの環境のコンソールで’‘R’‘とだけタイプしてRを実行できるなら、実行する用意はできています。

To add a new algorithm that calls an R function (or a more complex R script that you have developed and you would like to have available from QGIS), you have to create a script file that tells the processing framework how to perform that operation and the corresponding R commands to do so.

R script files have the extension .rsx, and creating them is pretty easy if you just have a basic knowledge of R syntax and R scripting. They should be stored in the R scripts folder. You can set this folder in the R settings group (available from the processing settings dialog), just like you do with the folder for regular processing scripts.

Let’s have a look at a very simple script file, which calls the R method spsample to create a random grid within the boundary of the polygons in a given polygon layer. This method belongs to the maptools package. Since almost all the algorithms that you might like to incorporate into QGIS will use or generate spatial data, knowledge of spatial packages like maptools and, especially, sp, is mandatory.

##polyg=vector
##numpoints=number 10
##output=output vector
##sp=group
pts=spsample(polyg,numpoints,type="random")
output=SpatialPointsDataFrame(pts, as.data.frame(pts))

The first lines, which start with a double Python comment sign (##), tell QGIS the inputs of the algorithm described in the file and the outputs that it will generate. They work with exactly the same syntax as the SEXTANTE scripts that we have already seen, so they will not be described here again.

When you declare an input parameter, QGIS uses that information for two things: creating the user interface to ask the user for the value of that parameter and creating a corresponding R variable that can later be used as input for R commands.

In the above example, we are declaring an input of type vector named polyg. When executing the algorithm, QGIS will open in R the layer selected by the user and store it in a variable also named polyg. So, the name of a parameter is also the name of the variable that we can use in R for accesing the value of that parameter (thus, you should avoid using reserved R words as parameter names).

Spatial elements such as vector and raster layers are read using the readOGR() and brick() commands (you do not have to worry about adding those commands to your description file – QGIS will do it), and they are stored as Spatial*DataFrame objects. Table fields are stored as strings containing the name of the selected field.

テーブルは``read.csv()``コマンドを使って開かれます。もし、ユーザによって入力されたテーブルがCSV形式でないならば、それはRによってそれがインポートされる前に変換されます。

加えて、ラスタファイルは``##usereadgdal``を使うことによる``brick()``に代わって``readGDAL()``コマンドを使って読み込むことができます。

If you are an advanced user and do not want QGIS to create the object representing the layer, you can use the ##passfilename tag to indicate that you prefer a string with the filename instead. In this case, it is up to you to open the file before performing any operation on the data it contains.

上記の情報により、現在私たちは最初のサンプルスクリプトの一行目(行頭がPythonコメントになっていない最初の行)を理解することができます。

pts=spsample(polyg,numpoints,type="random")

変数``polygon``はすでに``SpatialPolygonsDataFrame``オブジェクトを含んでいるので、ちょうど``numpoints`` メソッドのように、作成されたサンプルグリッドを加えたポイントの数を示す、``spsample``メソッドを呼び込むことができます。

私たちは``out``と名付けたタイプベクトルの出力を宣言してから、そこに(この場合は``SpatialPointsDataFrame``に)``out``と名付けた変数と``Spatial*DataFrame``オブジェクトを作成しなければならない。あなたの最終結果を保存する変数があなたが宣言して適切な値を含んでいる同じ名前を持つことを確認するように、あなたはあるらゆる名前をあなたの媒介変数として使うことができます。

In this case, the result obtained from the spsample method has to be converted explicitly into a SpatialPointsDataFrame object, since it is itself an object of class ppp, which is not a suitable class to be returned to QGIS.

もし、あなたのアルゴリズムがラスタレイヤを作成するなら、それらを保存する方法はあなたが``#dontuserasterpackage``オプションを使用するかどうかによります。もし、あなたがそれを使用するならば、レイヤは``writeGDAL()``メソッドを使って保存されます。そうでないならば、raster パッケージから``writeRaster()``メソッドが使われます。

もし、あなたが``#passfilename``オプションを使ったならば、たとえ``raster`` パッケージ(``writeRaster()``を伴った)が入力に使われないとしても、出力はそれを使って作成されます。

もし、あなたのアルゴリズムがなんのレイヤも作成しないで、代わりにコンソールにテキストで結果を作成するのならば、あなたは実行が終了したことを示すようにコンソールに指示をしなければなりません。このために、あなたは``>`` (‘greater’) サインを伴った印刷を欲する結果を作成するだけのコマンドラインを開始します。 すべてのほかの行の出力は表示されません。たとえば、ここにあるのはベクトルレイヤの属性として与えられたフィールド(列)の正常性テストを実行するアルゴリズムの説明ファイルです:

##layer=vector
##field=field layer
##nortest=group
library(nortest)
>lillie.test(layer[[field]])

The output of the last line is printed, but the output of the first is not (and neither are the outputs from other command lines added automatically by QGIS).

もし、あなたのアルゴリズムがあるグラフィックスの種類(``plot()``メソッドを使って)を作成するならば、次の行を加えます:

##showplots

This will cause QGIS to redirect all R graphical outputs to a temporary file, which will be opened once R execution has finished.

グラフィックスとコンソール結果はどちらも処理結果マネジャで見えるようになります。

更なる情報はSEXTANTEと共に提供されているスクリプトファイルを確認してください。それらのほとんどはかなり簡潔で、どのようにあなた自身の結果を作成するのかを理解することを十分に助けることでしょう。

GRASS: Geographic Resources Analysis Support System、地理的資源分析支援システム¶

GRASSを設定することはSAGAを設定することよりもそんなに難しくはありません。最初に、GRASSフォルダのパスが定義されなければなりませんが、あなたがウインドウズを利用している場合だけです。加えて、シェルインタプリタ(通常 msys.exe は、ほとんどのウインドウズディストリビューションためのGRASSに見つけることができます)が定義され、そのパスも設定されていなければなりません。

By default, the processing framework tries to configure its GRASS connector to use the GRASS distribution that ships along with QGIS. This should work without problems in most systems, but if you experience problems, you might have to configure the GRASS connector manually. Also, if you want to use a different GRASS installation, you can change that setting and point to the folder where the other version is installed. GRASS 6.4 is needed for algorithms to work correctly.

もし、あなたがLinuxを利用している場合は、GRASSが適切にインストールされているかと、それがコンソールから問題なく起動するかを確認するだけです。

GRASS algorithms use a region for calculations. This region can be defined manually using values similar to the ones found in the SAGA configuration, or automatically, taking the minimum extent that covers all the input layers used to execute the algorithm each time. If the latter approach is the behaviour you prefer, just check the Use min covering region option in the GRASS configuration parameters.

The last parameter that has to be configured is related to the mapset. A mapset is needed to run GRASS, and the processing framework creates a temporary one for each execution. You have to specify if the data you are working with uses geographical (lat/lon) coordinates or projected ones.

GDAL: Geospatial Data Abstraction Library、地理空間データ抽象化ライブラリ¶

No additional configuration is needed to run GDAL algorithms. Since they are already incorporated into QGIS, the algorithms can infer their configuration from it.

Orfeo ToolBox¶

Orfeo Toolbox (OTB) algorithms can be run from QGIS if you have OTB installed in your system and you have configured QGIS properly, so it can find all necessary files (command-line tools and libraries).

As in the case of SAGA, OTB binaries are included in the stand-alone installer for Windows, but they are not included if you are runing Linux, so you have to download and install the software yourself. Please check the OTB website for more information.

Once OTB is installed, start QGIS, open the processing configuration dialog and configure the OTB algorithm provider. In the Orfeo Toolbox (image analysis) block, you will find all settings related to OTB. First, ensure that algorithms are enabled.

Then, configure the path to the folder where OTB command-line tools and libraries are installed:

• Usually OTB applications folder points to /usr/lib/otb/applications and OTB command line tools folder is /usr/bin.
• If you use the OSGeo4W installer, then install otb-bin package and enter C:\OSGeo4W\apps\orfeotoolbox\applications as OTB applications folder and C:\OSGeo4W\bin as OTB command line tools folder. These values should be configured by default, but if you have a different OTB installation, configure them to the corresponding values in your system.

TauDEM: Terrain Analysis Using Digital Elevation Models、DEMを使用した地形分析¶

このプロバイダーを使用するためには、あなたはTauDEMコマンドラインツールをインストールしなければなりません。