DAY 11 Geoprocessing and Vector Analysis
第 11 天 地理处理和矢量分析

Geoprocessing

·Geoprocessing is any GIS operation used to manipulate data.

·A typical geoprocessing operation:

——takes an input dataset

——performs an operation on that dataset

——produces a result (often, but not always, another dataset)

·Geoprocessing includes:

——spatial analysis

——data management

Data Management Geoprocessing

·Used to develop, manage, and maintain datasets.

——create new features

——create new fields

——project data

——move, copy, and rename datasets

——etc.

Spatial Analysis

·Spatial data analysis is the application of mathematical operations to coordinate data and related attribute data.

·Spatial analysis involves methods whose results change when the locations of objects being analyzed change.

·Spatial analysis is the crux of GIS, the means of adding value to geographic data, and of turning data into useful information.

·Spatial analysis lets us answer questions about the world.

Where are Geoprocessing Tools?

·Analysis Tab > Tools

·Search

·Geoprocessing pane

·Catalog > Toolboxes > ProjectName.tbx

——create new toolsets

——copy/paste existing tools

Geoprocessing Help

·Each tool has online “help” information.

·Online help

https://pro.arcgis.com/en/pro-app/help/analysis/geoprocessing/basics/what-is-geoprocessing-.htm

Spatial Analysis

Vector Analysis、Raster Analysis
矢量分析、栅格分析

Types of Spatial Analysis
空间分析的类型

·Queries
·查询

·Measurements
·测量

·Transformations
·转换

·Descriptive Summaries
·描述性摘要

·Optimization
·优化

Transformation Tools (single layer)
变换工具（单层）

Transformation Tools (overlays)
变换工具（叠加）

·Methods of spatial analysis that combine datasets to produce new datasets…
·将数据集组合以生成新数据集的空间分析方法...

· …and hopefully new insights.
· ...并希望有新的见解。

·Transformations use simple geometric, arithmetic, or logical rules—but can be computationally complex.
·转换使用简单的几何、算术或逻辑规则，但在计算上可能很复杂。

· When using shapefiles (but not geodatabases), area, perimeter, and length must be recalculated after overlays.
· 使用 shapefile（而不是地理数据库）时，必须在叠加后重新计算面积、周长和长度。

Transformation Tools (extract)
变换工具（提取）

·Clip tool extracts input features that overlay the clip features.
·裁剪工具可提取叠加裁剪要素的输入要素。

·Clip features (the cookie cutter) are generally polygons.
·裁剪要素（饼干切割器）通常是多边形。

·Erase tool deletes input features that overlay the clip features.
·擦除工具可删除叠加裁剪要素的输入要素。

·Erase can be thought of as the inverse of clip.
·Erase 可以被认为是 clip 的反函数。

·Intersect tool extracts the portions of features that overlap in all input layers, and writes them to an output dataset.
·相交工具可提取所有输入图层中重叠的要素部分，并将其写入输出数据集。

·Inputs can be points, lines, and polygons.
·输入可以是点、线和面。

Transformation Tools (overlay)
变换工具（叠加）

Intersect tool output geometry can be specified.
可以指定相交工具输出几何。

Intersect Tool
相交工具

Input: line and polygon
输入：线和多边形

Output: line
输出：line

Input: line
输入：line

Output: point
输出：point

·Union tool writes features from all input layers to the output dataset, with attributes from the input features which overlap.
·联合工具会将所有输入图层中的要素写入输出数据集，其中输入要素中的属性重叠。

·Inputs must be polygons.
·输入必须是面。

· Identity tool writes attributes from identity features to input features that are overlapped by the identity features.
· 标识工具将标识要素中的属性写入与标识要素重叠的输入要素。

·Input features may be points, lines, polygons.
·输入要素可以是点、线、面。

·Identity features must be polygons.
·标识要素必须是面。

·Symmetrical Difference tool takes portions of input layer features that do not overlap, and writes them to the output dataset.
·对称差值工具获取不重叠的输入图层要素部分，并将其写入输出数据集。

Spatial Analysis
空间分析

·Merge tool combines input features from multiple input sources into a single new output feature class.
·合并工具将来自多个输入源的输入要素合并到单个新的输出要素类中。

·The input data sources may be point, line, or polygons, but they must all be the same.
·输入数据源可以是点、线或面，但它们必须相同。

·Append tool combines input features from multiple input sources into an existing feature class.
·追加工具用于将来自多个输入源的输入要素合并到现有要素类中。

·The input data sources may be point, line, or polygons, but they must all be the same.
·输入数据源可以是点、线或面，但它们必须相同。

·Usually used to combine similar layers with different spatial extents.
·通常用于组合具有不同空间范围的相似图层。

Queries and Reasoning
查询和推理

·Most basic of analysis operations.
·最基本的分析操作。

·The user interrogates the system about any aspects of its contents,
·用户询问系统内容的任何方面，

——but no changes occur in the database,
——但数据库没有发生任何变化，

——and no new data are produced.
——并且不会产生新数据。

·Identify and select features interactively.
·以交互方式识别和选择要素。

·Identify and select attributes interactively.
·以交互方式识别和选择属性。

·Use links between attributes and features.
·在属性和特征之间使用链接。

·Select by attribute (using SQL).
·按属性选择（使用 SQL）。

·Select by location.
·按位置选择。

Measurement
测量

·Simple numerical values that describe aspects of geographical data.
·描述地理数据各个方面的简单数值。

·Properties of objects
·对象的属性

——length (perimeter)
——长度（周长）

——area
——面积

·Relationships between objects
·对象之间的关系

——distance
——距离

——direction
——方向

——slope
——坡度

——aspect
——方面

Measurement (Area of Convex
测量（凸面面积

pick a vertex at random
随机选取一个顶点

with each other pair of adjacent vertices:
与每对相邻顶点：

construct a triangle
构造一个三角形

find the area of the triangle
求三角形的面积

add up the areas of all the triangles
将所有三角形的面积相加

this works for convex polygons, but what about concave polygons, or polygons with holes?
这适用于凸多边形，但凹多边形或带孔的多边形呢？

Measurement is easy to do in a GIS, difficult and tedious on a paper map
在 GIS 中很容易进行测量，但在纸质地图上则困难而乏味

Calculating Measurement
计算测量

Automatically updated only for feature classes in a geodatabase. Not updated in shapefiles!
仅对地理数据库中的要素类自动更新。在 shapefile 中未更新！

never automatically updated
从不自动更新

Shape
形状

Compactness is a function of the area of a polygon divided by its perimeter.
紧凑度是多边形面积除以其周长的函数。

A small perimeter for a given area implies a more compact shape.
给定区域的小周长意味着更紧凑的形状。

Circles are the most compact shape.
圆圈是最紧凑的形状。

Distance
距离

Great circle equations for spherical distance (latitude/longitude).
球面距离（纬度/经度）的大圆方程。

https://en.wikipedia.org/wiki/Great-circle_distance

Pythagorean theorem for Euclidean (straight line) distance.
欧几里得（直线）距离的勾股定理。

https://en.wikipedia.org/wiki/Euclidean_distance

Manhattan, or taxicab, distance (city block) measured along coordinate axes at right angles.
曼哈顿或出租车沿坐标轴以直角测量的距离（城市街区）。

Proximity
接近

Near tool computes distance between point features in one layer and the closest feature in another layer within a specified search radius.
邻近工具用于计算指定搜索半径内一个图层中的点要素与另一个图层中最近要素之间的距离。

Results are recorded in the input dataset’s attribute table
结果将记录在输入数据集的属性表中

Point Distance tool computes distance between point features in one layer and all points in another layer within a specified search radius.
点距离工具用于计算指定搜索半径内一个图层中的点要素与另一个图层中的所有点之间的距离。

Output is a table.
输出是一个表。

Buffer tool builds new objects by identifying all areas that are within a specified distance of the original objects.
缓冲区工具通过识别原始对象指定距离内的所有区域来构建新对象。

Create Thiessen Polygons tool takes input point dataset and outputs polygons, one polygon per point.
创建泰森多边形工具获取输入点数据集并输出多边形，每个点一个多边形。

Each polygon represents the area that is closer to the contained point than to any other point.
每个多边形表示比任何其他点更靠近包含点的区域。

Transformation
转型

Feature to Polygon tool converts “closed areas” of lines into polygons
要素转面工具将线的“闭合区域”转换为面

Feature to Point (centroid) tool creates point features located at the geometric center of the input polygons.
要素到点（质心）工具用于创建位于输入面几何中心的点要素。

Feature Envelope tool creates a rectangular area (envelope)that completely contains the input feature’s geometry.
要素包络矩形工具将创建一个矩形区域（包络），该区域完全包含输入要素的几何图形。

Generalization
普遍化

Reduce the geometric complexity of features, for cartographic representation at small scales, or for special purposes.
降低要素的几何复杂性，用于小比例的制图表达或特殊用途。

Simplify Line (cartography) tool simplifies lines by removing extraneous bends while preserving essential shape.
简化线 （制图）工具通过删除无关的弯曲来简化线，同时保留基本形状。

Dissolve tool aggregates features based on specified attributes
融合工具根据指定属性聚合要素

Large numbers of polygons can result from overlays where common boundaries appear in both datasets, because the datasets...
在两个数据集中都出现公共边界的叠加层可能会导致大量的多边形，因为数据集...

were collected at different times
在不同时间收集

were collected by different people / organizations
由不同的人/组织收集

were collected at different resolutions
以不同的分辨率收集

Eliminate tool removes unwanted polygons from a dataset— merges selected polygons with neighboring polygons with the largest area, or largest shared border
消除工具从数据集中移除不需要的多边形 - 将所选多边形与具有最大面积或最大共享边界的相邻多边形合并