This article is a study note, the original text comes from the official account of [Groundwater Environment Network], and the original author is Wang Xuewei.
https://mp.weixin.qq.com/s/gsCuBk3lwkOX_jfekBdZlg
Please indicate the source of the reprint.
What is a Spatial Overlay Map?
That is to say, multiple layers of the same research area that represent different factors are stacked together to form a three-dimensional map, which can also be called a stacked map.
I haven't found an accurate definition of this term, so I will explain it according to my own understanding.
The overlay plot (overlay plot) described in this article is different from the plot formed by overlay analysis (overlay analysis) in ArcGIS.
The former is only the simultaneous display of multiple layers, while the latter has operations between multiple layers.
drawing summary
The main implementation operation lies in Surfer.
According to the type of layer, such as graded color map, contour map, etc., select the software used with surfer.
If you need to make a hierarchical map, ArcGIS+Surfer is the best choice, and the operation steps can be carried out directly according to Wang Xuewei's tutorial.
If you need to make a contour map, you can directly use Surfer to do it, because Surfer has great advantages in making contour maps.
No matter what type of graph you want to make, you need an attribute table. The format of the attribute table can be Excel, dBase table, Text, etc., depending on the file type supported by Surfer for making grid files.
Another necessary document is the study area boundary shp map.
Why do you need to convert raster to point in ArcGIS?
Because the HWSD soil database used in the original text is a raster file, Surfer cannot directly recognize it, so a bridge is needed to connect it.
This bridge is a point file, a file containing coordinate xy points and coordinate point attributes. Because Surfer generates the mesh by spatially interpolating the attributes in the point file.
The raster conversion point in ArcGIS is to convert all the raster cells into a point file with coordinates, and this point file surfer can be recognized.
Although this method can realize the interaction between the two software, the accuracy of the grid generated by Surfer through point files will be different from the grid in GIS, because Surfer is a grid obtained through point interpolation. This difference results in slightly different classification area boundaries.
Previously, some scholars published a method about the mutual conversion of the two grids, which can achieve perfect error-free conversion.
Bai Shibiao, Lu Guonian, Yang Yipeng. The conversion method of ArcGIS and Surfer grid files[J]. Surveying and Mapping Bulletin, 2005, 000(002):48-50,54.
The main operation steps in Surfer
1. Make a grid file
Open Surfer, click "Home" -> "Grid Data (grid data)", open the T_SAND.dbf file. X, Y, and Z are set as shown in the figure (where Z is the attribute data, the name may be different, and the rest of the attributes can be left alone for the time being), click OK.
2. Make a grid file with borders (whitening borders)
Click "Grids (grid)" -> "Blank (whitening)", Input Grid (input grid) select the grid file just made, Blanking Polygon boundary (white polygon boundary) select "Yibin.shp" file (from Line file exported in ArcGIS), Loaded 1 polygons total, select "Blank outside (whitening outside)", select the export path, New layer type (new layer style) I choose "Contour (contour)" here. Get a bounded contour plot.
3. Beautify pictures
Select "Contours-T_SAND_out.grd" in the directory, "Properties (properties)" will appear the property options, in the Level tab, "Filled Contours" is checked, and choose a favorite in the "Fill Color" below Color, "Style" in "Major Contours" and "Minor Contours" is set to "Invisible". You will get the following picture. (I won’t take screenshots one by one here, you can explore and beautify pictures according to your own preferences)
You can see that there are coordinate information on the bottom and the right side, and there are scale marks around. We will now cancel the display of these redundant things. Take "Bottom Axis" as an example. Select "Bottom Axis" in "Contents", uncheck the "Labels" option "Show" under the "General" tab in "Properties", and set the "Style" under "Major Ticks" in the "Ticks" tab to " None".
4. Set view properties
Select "Map" in "Contents", and adjust the viewing angle under the "View" tab in "Properties". The parameter settings are shown in the figure. It should be noted that the "Field of view" option will work only when "Projection" needs to be set to "Perspective". (The perspective effect of far small and near large)
Repeat the above steps for the rest of the pictures, so I won’t go into details here. The final effect is as shown in the figure below. (Small far and near large are not good-looking in the overlay picture, so it was canceled)
After selecting all the graphics, the "Size" and "Align" in the "Layout" tab can assist in alignment. Right-click graphics and select "Group" to combine them to prevent subsequent adjustments from disturbing the alignment.
Then select "Polyline" in the "Home" tab, select the endpoint to draw the connection line, the effect is as shown in the figure below.
However, you will find that the perspective relationship is wrong, and the lines behind are displayed in front. There are two reasons here: one is that the layer of "line" is above the "surface", just adjust the order of the layers, select the line to be adjusted, and click "Send to Back" in the "Layout" tab; It is the "whitened area" of the graphics, which is not white, but transparent. Some adjustments are required at this time. Select the layer that needs to be adjusted, in the "Properties (Attributes)", under the "General" tab, "Blanked Regions (whitening area)", "Pattern" select "Solid", "Foreground color" select "White", just fine La! If you need to mark the text, select "Text" in "Home" and input the text in the graphic.
export
Finally, "Export" in "File" is enough, and the export file type can be selected as needed.
