Detailed explanation of land use change analysis-vector
Land use type classification
Before proceeding with other operations, first divide the land use types into six categories, namely:
- Arable land (1)
- woodland(2)
- grass (3)
- waters (4)
- Urban and rural, industrial, mining and residential land (5)
- Unused land (6)
The specific processing steps are as follows:
1 Statistics on the area/proportion of different land use types
1.1 Operation steps
Step1：
Step2: Calculate area
Since the raster does not have an attribute table, convert the raster into area features to generate an attribute table, and add a field to the generated attribute table.
Method to add area field: Click Table Options → Add Field…, add area field: (To calculate the area, this layer must be converted to a projected coordinate system)
After adding the area field, right-click the Area field and click [Calculate Geometry] to calculate geometry.
[Note] The gray color of the calculated geometric area indicates that there is no spatial reference or the correct spatial reference is not set. At this time, the correct spatial reference should be set || or because it is not an area feature, the calculated geometry cannot be used
Use [Abalysis Tool] → [Statistics] → [Summary Statistics] to count the total area of various types.
① Drag in the converted vector data
② Select "Area" in the field
column ③ Select "SUM" in the Statistic Type column (calculate the total amount of various land areas), you can also count the minimum value, maximum value, average value, etc.
④Case field select “gridcode”.
Step3: Calculate the proportion
(5) Open the table and you can see the areas of various types of land. If you need to calculate the proportion of various types of land, you can use the area of a certain type of land/total area. Table can be imported into Excel, or summary statistics can be performed directly in Table.
2 Statistics of the area of various land use types in different regions
2.1 Operation steps
3 Land use change transfer matrix
3.1 Research ideas
1. Perform a fusion Dissolve operation on the land use data of the two periods, so that there is only one record for each land use type.
2. Then perform the Intersect operation on the fusion results to analyze land use changes.
3. Export to Excel table
4. Use pivot tables for statistics in Excel
3.2 Operation steps
4 Analyze land use vector data graphics and attribute changes in different periods
4.1 Research ideas
You can first perform a Union operation on the two layers, and then create a new field in the result to analyze the changes in attributes.
- If the attribute has not changed, assign it a value of 1
- If the attribute changes, it is assigned a value of 0.
4.2 Operation steps
1. Put the properties of the two layers into one layer.
Use the GP tool Union. Pay attention to the JoinAttribute and select All, that is, all fields of the two layers are included in the result.
The attribute table is as follows:
reference
1. Zhihu - Detailed explanation of land use change analysis in ArcGIS