GIS basic software and operation (vi)

Original GIS basic software and operation (vi)

Practice VI. Application of spatial analysis

1. Deepen the understanding of the basic principles and methods of buffer analysis;
2. Master the technique method of creating buffer distance drawing.
3. Master the ability to use the buffer analysis method to solve the geo-spatial analysis problem.

1. Distance mapping-creating buffers

Data preparation: Layer file point.shp,lline.shp,polygon.shp

Buffer analysis for 1.1-point feature layers

1) Create a new map document in ArcMap and load the layer: Studyarea,point

2) Open Arctoolbox, execute command <spatial analyst Tools >-< distance analysis >-< Euclidean distance, set each parameter as shown

Note: The Find distance feature in ArcView GIS 3.x and ArcGIS
The << Euclidean distance > mapping function is the same.

Click on the "Environment" button

Set "Scope" in "processing range" to make it the same as Studyarea

1) displays and activates the new raster theme generated by POINT.SHP, Eucdist_ (for example).

In the analysis, if one or more features in the point layer are selected, buffer analysis is only for that feature, otherwise, all features of the entire layer.

Buffer analysis for 1.2-line feature layers

1. In ArcMap, create a new map document, load the line layer, and click on the Standard toolbar to narrow the map appropriately.

1. Select the two lines in the layer line for buffer analysis, and note how the buffer analysis of the comparison line differs from the point's buffer analysis.

Method: Open Arctoolbox, execute command <spatial Analyst
Tools >-< Distance Analysis >-< Euclidean distance >;

Set "Scope" in "Processing range" in environment settings to "same as display"

1. Buffer analysis is performed on the entire line level, and the differences between the results are observed and analyzed (e.g.).

1.3 Buffer analysis for multi-side layers

Create a new map document in ArcMap, add layers: polygon, perform buffer analysis, and see how the buffer analysis of polygons differs from the point-and-line buffer analysis.

The same as the buffer that created the line, the map is scaled down appropriately, and the scope in the processing range in the environment is the same as display

2. Comprehensive application Experiment 2.1 water pollution control

The point graph level represents the location distribution of water sources, such as wells, and requires the use of buffer analysis to identify key areas of water pollution prevention.

Steps:

1. In ArcMap, create a new map document and add a point layer data point.shp that represents the distribution of the water source.

2. Open Arctoolbox, execute <spatial Analyst > Tools >-< distance >-< Euclidean distance > command.

3. Displays and activates a new raster layer eucdist (such as) generated by POINT.SHP.

1. Right-click on the raster layer eucdist, execute the Properties command in the context menu, set the layer display symbol, adjust the classification and set the legend display mode.

The new raster layer shows the distance from the nearest well for each grid in the area, where the red grid is closest to the individual wells and has the greatest impact on the water source; The blue grid is farthest from each well and has minimal impact.

1. In this case, it is considered that the area within 0.1 of each well has the greatest impact on water quality, so open the Spatial Analysis toolbar (first make sure that the spatial analysis extension is already loaded), execute menu commands <Spatial> analyst> tools >-< Map algebra >-< Raster Calculator; The area within the distance ≤0.1 is extracted as a buffer for special pollution prevention and control. (e.g.).

2.2 Grading of contaminated areas

Assume that the point layer represents a number of points of pollution sources, from the source of pollution, the situation is different, the closer to the source of pollution, the more serious, according to the source of the vicinity of the sources of grading.

(1) In ArcMap, create a new map document, add layers: Point, Studyarea. Open Arctoolbox, execute <spatial > Analyst > Tools >-< Distance Analysis >-< Euclidean distance > command to get a new raster layer eucdist_shp3;

Note: The specified range is the same as the layer Studyarea

(1) Open the Spatial Analysis toolbar, execute the command:< spatial Analysis >-< Raster calculator, raster layer eucdist_shp3t based raster calculations, respectively ([eucdist_shp3]≤0.1) of the region, and ( eucdist_shp3] >=> 0.1& (eucdist_shp3] <=> 0.15) to get raster layers: "Restercal3" and " Restercal2 ";

(1) Reclassify the raster layer: "Restercal2" (Perform command < spatial analysis >-< reclassify > command) so that the original true (1) value is 0,false (0) value 1 and a new raster layer is obtained: Reclass_ Rast3.

(1) Classify the layer "RESTERCAL3" with "reclass< reclassify > Raster layer" RASTERCALC4 "grading by grade" To get the result raster layer "Reclass > Of_rast2".

(The regional pollution level for <=0.1 is set at 1,) =0.1 and the <=0.15 region level is set to 2,
>0.15 regional level is set to 3)

Note: In this example, the dist_of_point (2)-(4) operation can actually be reclassified directly to the raster layer.

2.3 Extent of urbanization impact

Assume that the urban layer represents some small industrial towns in the process of urbanization and also includes a natural ecological reserve. The urbanization of these small towns will have some expansion effect on the surrounding area, but there is no polluting industry around 0.05 of the natural ecological Protection Area, so the extent of urbanization is restricted.

(1) In ArcMap, create a new map document, add layers: urban.shp, urbanarea,<spatial > Analyst > Tools >-< Distance Analysis >-< Euclidean distance > command, The analysis of the urban layer is carried out, respectively, the Euclidean distance analysis of the protected area and the town, the protected area and the town need to do the Euclidean distance analysis separately, take the town as an example: Click to select-Select by attribute

Note: In the environment setting, the range of processing range is selected as: With Layer
Urbanarea Same

The buffer zone of the town

Buffer zone of the reserve

(1) Perform raster calculations on the layer dist_nature (using the raster calculator in the spatial Analysis tool), extract the area of the <=0.05, and reclassify it so that the original true (1) value is 0,false (0) with a value of 1 and "reclass> of calculation" is obtained.

(1) The area of the layer dist_res is calculated to extract <=0.06 from the raster, and the calculation 2 is obtained.

(1) The raster calculation (using the raster calculator in the Spatial Analysis toolbar) that multiplies the layer "Reclass of > Compute" with "calculated 2", Gets the "Calculate 3" layer of the urbanization range.

(1) Carefully consider the above procedure, to explain the results obtained

Urban expansion areas that do not affect protected areas

Wang Smooth
Comment posted: 2016-01-14 14:56:12
Updated on: 2016-04-28 21:41:54
Original link: Http://www.wshunli.com/2016/01/14/GIS basic software and operation-Six/
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GIS basic software and operation (vi)