Basic GIS software and operations (eight)

Original GIS basic software and operation (eight)

Practice Viii. Geography Modeling

Geographic Modeling: Model Builder modeling and analysis of soil erosion risk

Understanding the ModelBuilder Operator interface

1: Add data or tools from the hard drive into the model, data can also be dragged from ArcMap or arccatalog directly into the model, and the tool can be dragged directly from the Arctoolbox to the model

2: Show all model features and fill the ModelBuilder window

3: Free zoom, click this button, press and hold the mouse, move the mouse up or down to zoom the flowchart in ModelBuilder

4: Select to select a data frame in the Model, tool chart box

5: Add a connection to connect data and tools

6: Run the selected process or the entire model

Determine the target, load the data

Objective: To obtain [map of soil erosion hazard distribution]

Factor determination: Slope, soil type, vegetation cover

Data: Vector data: Study Area boundaries (Study
Area), vegetation (vegetation), raster data: Soil type raster (Soilsgrid)

(1) Create a new map document in ArcMap

(2) Adding vector data: studyarea, vegetation, raster data Soilsgrid (also checked: Hold down SHIFT while clicking)

(3) Open Arctoolbox, activate Spatial analyst Spatial Analysis extension and 3D Analysis expansion module (execute menu command [tools]>>[extension], select "Spatial Analysis module" and "3D Analysis" in the dialog box that appears)

(4) Set the symbol for the vegetation layer to [unique value rendering] According to the attributes [Vegtype] in Vegetaion, and set the soil type raster's symbol for [unique value rendering] According to the property [value] in the Soilsgrid layer, set the bounds and padding of the layer Studyarea, and adjust the order of each layer to get the following effect:

(5) Save the map document as [EX8.MXD]

Create a model

On the basis of the previous operation

(1) in ArcMap, open Arctoolbox, execute the menu command: [Tools]>>[Options], in the [Options] Settings dialog box, set [my toolbox location] in the [Spatial processing] Options page, specify it as a path, such as [D:\arcgis], Because the model created below will be saved to a file with the suffix [. TBX], which is stored under the path set above.

(2) In Arctoolbox, right click on the root target [Arctoolbox], execute [New Toolbox] command in the context menu, will create a toolbox in [D:\arcgis], rename the new toolbox, such as [geosptial]

(3) Right click on the new Toolbox [geosptial], in the context menu, execute the command: [New]>>[model], the [ModelBuilder] application window will open:

Note: For existing models, right-click on the model and select [edit] to open the [ModelBuilder] window and edit the existing model.

Edit Model

On the basis of the previous step

(1) in the [ModelBuilder] window, execute the menu command: [model]>>[Model properties]

In the General Options page, set the name and label of the model

Set the analysis scope to the study area in the [Environment variables] Options page

[Same as Layer "Studyarea"] by setting [General Settings] [Output RANGE] in [environment settings]

(2) in the [ModelBuilder] window, execute the menu command: [model]>>[diagram Properties]

(3) from ArcMap, drag and drop layers [vegetaion], [Soilsgrid] to
[ModelBuilder] window; Drag and drop the tool {to raster] from [Arctoolbox] into the [ModelBuilder] window (This tool is under the conversion tool >>[dem to the grid)

(4) in the [ModelBuilder] window, double-click the tool chart box [dem to Raster] and specify the input Usgsdem file in the Tool Settings dialog box that appears: [elevation.dem]-Locate the file on your hard disk by the [Browse Open] button on the right side of the input box.

(5) Drag and drop the tool [slope] from [Arctoolbox] into the [ModelBuilder] window (this tool is under [3D Analyst tool]>>[Grid surface]), and in the [ModelBuilder] window, click [Add Connection] button (as indicated by the Red arrow) to connect the derived data frame [DEMTORA_ELEV1] with the tool chart frame [slope]. When finished, the effect is as follows:

Right click on the frame [output raster] To rename it: [Slope chart]

(6) Drag and drop the tool [reclassify] from [Arctoolbox] into the [ModelBuilder] window (this tool is under [Spatial analyst Tools]>>[reclassify]), and in the [ModelBuilder] window, click [Add Connection ] button to connect the derived data frame [slope Chart] With the tool chart box [reclassify]. When finished, the effect is as follows:

(7) in the [ModelBuilder] window, double-click the tool frame [reclassify] and reclassify the slope in the [Reclassify] Tool Properties dialog box:

Here we use the Info data table [Slopereclass] to achieve reclassification, in, click the [Load] button to find the data table [Slopereclass], the slope will be divided into 10 categories according to the set values in this data table.

There are special fields [from], [to], [out], [MAPPING] in [Slopereclas], which can be used for reclassification:

In the [ModelBuilder] window, right-click on the back of the tool map box [reclassify]
[Output RASTER] renamed it: [Reclassify slope map]

(8) Drag and drop the tool [feature to raster] from [Arctoolbox] into the [ModelBuilder] window (This tool is under the conversion tool]>>[to raster]–), and in the [ModelBuilder] window, click the [Add Connection] button to set the data frame [Vegetaion] is connected to the tool chart box [feature to raster]. When finished, the effect is as follows:

Rename the [output raster] After the tool chart box [feature to raster] to [vegetation grid].

Double-click [Vegetaion] to connect to the tool frame [feature to raster], in the dialog box that appears, set the field to [Vegtype], OK.

In [ModelBuilder], right-click the frame [feature to raster] and execute the [run] command. [Note: This step is more important]

(9) Drag and drop the tool [weighted overlay] from [Arctoolbox] into the [ModelBuilder] window (this tool under [Spatial Analyst Tools >>[Overlay Analysis]), right click on the tool frame [weighted overlay] After the result data frame changed to [Soil erosion grid], as shown in the finished effect:

(10) in the [ModelBuilder] window, double-click the tool frame [weighted overlay] and click the [Add Raster Row] button (indicated by the Red arrow) in the [Weighted Overlay] Tool Settings dialog box that appears.

In the Add Weighted Overlay Layer dialog box, specify the parameters as shown and add the factor [Soilsgrid] to the weighted overlay analysis process:

Click [Add Raster] again in the [Weighted Overlay] dialog box
Row] button, set the parameters as shown, and add the factor [vegetation grid] to the weighted overlay analysis process:

Click [Add Raster] again in the [Weighted Overlay] dialog box
Row] button, set the parameters as shown, and add the factor [reclassify slope map] to the weighted overlay analysis process:

Three factors when you are finished, go back to the [Weighted Overlay] Tool Settings dialog box to set the weight of the factor [soilsgrid], [vegetation grid], and [reclassify slope map] to: [25%], [25%], [50%]

(11) Setting factor [Soilsgrid]: According to the influence of different soil types on the risk of soil erosion, different soil types given different values, the value of 1 indicates that the risk of soil erosion is low,

(12) Setting factor [vegetation grid]: Depending on the impact of different vegetation types on the risk of soil erosion, different vegetation types given different values, the value of 1 means that another day, the risk of soil erosion is low,

(13) Set factor [reclassify slope chart]: The risk system of soil erosion under different slope is smaller, the risk coefficient of soil erosion is bigger in the area with larger slope, the different slope corresponds to different values, the value 1 indicates that the risk of soil erosion is low,

The final completed model diagram is as follows:

Execute model, view results

(1) Execute the menu command in the [ModelBuilder] window: [model]>>[run the entire model]. Please be patient and wait for the calculation result: required (3-5s)

(2) in the [ModelBuilder] window, right click on the frame [soil erosion grid] in the context menu that appears, select [Add to display window]. The soil erosion risk grading raster data [Hazrad] represents the risk level of soil erosion in the study area, 1 indicates that there is less likelihood of soil erosion, and 6 indicates that soil erosion is highly likely.

Wang Smooth
Comment posted: 2016-01-14 14:56:23
Updated on: 2016-04-28 21:40:56
Original link: Http://www.wshunli.com/2016/01/14/GIS basic software and operation-eight/
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Basic GIS software and operations (eight)