A spatial analysis is analysis techniques based on locations and shapes of geographical objects. Its objective is to extract and transmit spatial information. Powerful spatial analysis capability is a main feature of GIS.
There are two types of spatial data: vector data and raster data. Therefore, spatial analysis functions can be divided into two categories: spatial analyses applied to vector data and those applied to raster data.
Vector Analysis
Vector analysis functions include: Buffer analysis, Overlay analysis, Dynamic Segmentation, etc.
Buffer Analysis is a process of building zones with a certain width around point, line, or region geometric objects according to a specified buffer distance.
Overlay analysis is a process of generating a new dataset by overlaying two datasets with different themes. An overlay analysis result carries over the attributes of the features from two or more original layers.
It is used to introduce the principle and concepts of dynamic segmentation. For example, the general process, create route, calibrate route, create the event table, manage the routes and event tables.
Raster Analysis
Raster data structure is simple and intuitive, and thus easy to process and operate on using computers. It is a basic data format commonly used in GIS. Raster-based spatial analyses are basics of GIS spatial analyses.
The raster analysis functions in the application program include: settings for raster analysis environment, surface analysis, statistic, converter, distance raster, interpolation, histogram, hydrology, grid value and so on.
Set the environment for the raster analysis uniformly, including the geographical range of result datasets, clip region and default output resolution.
Surface analysis is a method to obtain information or generated surface based on a surface model. Grid surface analyses include isoline extraction and isoregion extraction.
Raster statistics provides multiple methods to calculate the cell values of raster data.
The converter is used to implement the conversion between vector and raster data, and thin the raster.
The distance raster is used to calculate the distance from a cell to the adjacent cell, including spatial and cost distance. The distance raster provided by application can calculate the distance, shortest path and least cost distance.
In real GIS applications, values at un-sampled points usually need to be predicted using values at sampled points. That can be realized by interpolation. Interpolation generates a continuous surface and the value at every point can be obtained from this surface.
How to use the histogram to do raster data statistics.
Hydrology Analysis can help us understand the hydrological characteristics of raster data, You can calculate the fill sink, flow direction, flow length, flow accumulation, subbasin and so on.
Query the grid value where the mouse is. The query information includes the cell datasource, dataset, coordinate value, line number and grid value.