arcgis用矢量点来提取栅格属性
https://wenku.baidu.com/view/229d431a5727a5e9856a61f3.html
ArcGIS 教程：多值和值的提取至点 (空间分析 )
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Arcgis导入采样点：
https://blog.csdn.net/lucky51222/article/details/80038108
注：导入自己的坐标点时，需要确定坐标系，且只能时地理坐标系！一般GPS为WGS84
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坐标系定义：
1、定义地理坐标系
数据没有任何空间参考时，显示为Unknown！时就要先利用Define Projection来给数据定义一个地理坐标系。TOOL工具，
>>>
>>>
>>>WGS1984
>>>
>>>
>>>WGS1984
2、给已经定义地理坐标系的文件定义投影坐标系。
>>>选择 UTM---WGS1984 49N
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栅格数据地理坐标系转换：
（1）原始坐标系：WGS_1984_UTM_ZONE_47N
（2）目标坐标系：GCS_krasovsky_1940
（3）问题：使用Project工具，在选择geographic transformation时，没有直接转化的参数，该怎么解决这个问题
（4）或者能实现逆转化也行，有没有什么好办法，请各位大神指点！
答：
打开arcmap设置坐标为GCS_krasovsky_1940，打开你的数据，然后道出数据，坐标系选择数据框，就转出来了
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下载的30mLU图分为多个栅格部分，需要将其修剪每一个栅格，最后图像合并（融合）
1.构建小的矢量图，裁剪掉栅格图锯齿状边缘；
https://blog.csdn.net/u010608964/article/details/81708767 （选择Edit操作栏最后一个“创造矢量”按钮）
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属性表数据转换为Excel（矢量文件）
arcGIS中属性表导出到EXCEL里的步骤为：
一、首先我们在ArcTools软件的工具箱中点击选择转换工具-Excel-表转Excel。
二、接着我们再选择我们要输入的表所在的图层，再选择导出路径和设置文件名，确认无误之后我们再点击确定就可以了。
三、接着我们再打开目标文件点击查看，这时我们就可以看到arcGIS中属性表已经成功导出到EXCEL里了
栅格文件：
Exporting a raster attribute table
You can export a raster attribute table just as you would export any other attribute table.
You need to be viewing the raster attribute table. See
Viewing a raster attribute table for these steps.
Click the
Table Options button
and click
Export.
and click
Export.
Click the
Export drop-down arrow on the
Export Data dialog box to choose to export
All records or
Selected records.
The
Selected records option is only available if records are selected in the table.
Click the
Output table browse button
and navigate to the folder or geodatabase in which you want to place the exported data.
and navigate to the folder or geodatabase in which you want to place the exported data.
Click the
Save as type drop-down arrow and click the format to which you want to export the data.
Type a name for the exported table.
Click
Save.
Click
OK.
一/.arcgis中怎么把两个栅格图像合并在一起
栅格数据合并：
数据管理工具--栅格--栅格数据集--镶嵌至新栅格
参数设置：
|
Parameter
|
Explanation
|
Data Type
|
|
inputs
[input,...]
|
The raster datasets you want to merge together.
|
Mosaic Dataset ; Composite Layer ; Raster Dataset ; Raster Layer
|
|
target
|
The raster to add the input rasters. This raster dataset must already exist. By default, the target raster is considered the first raster in the list of input raster datasets. You can create an empty raster using the
Create Raster Dataset
tool.
|
Raster Dataset
|
|
mosaic_type
(Optional)
|
The method used to mosaic overlapping areas.
|
String
|
|
colormap
(Optional)
|
The method used to choose which color map from the input rasters will be applied to the mosaic output.
|
String
|
|
background_value
(Optional)
|
Use this option to remove the unwanted values created around the raster data. The value specified will be distinguished from other valuable data in the raster dataset. For example, a value of zero along the raster dataset's borders will be distinguished from zero values in the raster dataset.
The pixel value specified will be set to NoData in the output raster dataset.
For file-based rasters and geodatabase rasters, the
Ignore Background Value
must be set to the same value as NoData for the background value to be ignored. Enterprise geodatabase rasters will work without this extra step.
|
Double
|
|
nodata_value
(Optional)
|
All the pixels with the specified value will be set to
NoData
in the output raster dataset.
|
Double
|
|
onebit_to_eightbit
(Optional)
|
Choose whether the input 1-bit raster dataset will be converted to an 8-bit raster dataset. In this conversion, the value 1 in the input raster dataset will be changed to 255 in the output raster dataset. This is useful when importing a 1-bit raster dataset to a geodatabase. One-bit raster datasets have 8-bit pyramid layers when stored in a file system, but in a geodatabase, 1-bit raster datasets can only have 1-bit pyramid layers, which makes the display unpleasant. By converting the data to 8 bit in a geodatabase, the pyramid layers are built as 8 bit instead of 1 bit, resulting in a proper raster dataset in the display.
|
Boolean
|
|
mosaicking_tolerance
(Optional)
|
When mosaicking takes place, the target and the source pixels do not always line up exactly. When there is a misalignment of pixels, a decision needs to be made whether resampling takes place or whether the data should be shifted. The mosaicking tolerance controls whether resampling of the pixels take place or if the pixels should be shifted.
If the difference in pixel alignment (of the incoming dataset and the target dataset) is greater than the tolerance, resampling will take place. If the difference in pixel alignment (of the incoming dataset and the target dataset) is less than the tolerance, resampling will not take place (instead, a shift is performed).
The unit of tolerance is a pixel, where the valid value range is 0 to 0.5. A tolerance of 0.5 will guarantee a shift takes place. A tolerance of zero guarantees resampling, if there is a misalignment in pixels.
For example, the source and target pixels have a misalignment of 0.25. If the mosaicking tolerance is set to 0.2, then resampling will take place since the pixel misalignment is greater than the tolerance. If the mosaicking tolerance is set to 0.3, then the pixels will be shifted.
|
Double
|
|
MatchingMethod
(Optional)
|
Choose the color matching method to apply to the rasters.
|
String
|
二/.从全国土地利用图中裁剪研究区
后面裁剪其他年份注意同意坐标系统
2018年省份合并后存在空格，需要使用最近邻土地利用类型将其填充：
三/ . 工作中遇到一个栅格图中有一些区域或者几个别的点为nodata值，或者已知数据中某个点的值质量较差想用邻近值替换掉。这时可以使用nibble工具填充
1、首先使用栅格计算器中的con和isnull函数组合，为原始图像A中nodata赋一个值（否则nodata不参与运算），如9999或其他，得到图像B。（工具：Spatial Analyst Tools / Map Algebra / Raster Calculation
首先利用Con() 函数进行条件的限制；
再利用isnull()函数选出为空的值
将控制设置为0
函数表达式为：Con(IsNull(raster1),0,raster1)
注意：要把第二个raster1加上，否则，计算结果中只有NoData转换成0之后的值，原始不为零的值就会失去。）
2、在nibble工具中Input raster中输入B图像作为待处理的图像，input raster mask 中输入掩膜文件，即A图像作为掩膜，A中的nodata采用邻域赋值。
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PLOS ONE文章土地利用分类：
四/ 重分类
分类后，在非编辑状态 可以增加属性表列，右键选择删除列，编辑状态给列赋值。
五/环境变量获取
slope / altitude 提取
Tips：Arcgis开始时一直提示创造金字塔：告诉你你的栅格还没建金字塔文件，金字塔文件可以加快栅格的显示速度，问你需要不需要建金字塔文件，这个主要是用来加快栅格在不同比例尺下的显示速度的，按yes即可
投影转换
六/arcgis矢量数据如何分级做缓冲区（不适用于做本研究，由于会把NODATA区域全部视为最大距离，仅仅在缓冲区宇存在数据）（X）
打开arctoolbox，依次打开analysis tools，找到proximity，在该工具下找到multiple ring buffer
正确方式：计算欧式距离（图中任意一点到最近河流的距离）
重采样方法选择：
1、栅格重采样主要包括三种方法：最邻近法、双线性内插法和三次卷积插值法。
2、
最邻近法是把原始图像中距离最近的像元值填充到新图像中；双线性内插法和三次卷积插值法都是把原始图像附近的像元值通过距离加权平均填充到新图像中。
3、默认情况下，采用最近邻分配重采样技术，这种方法同时适用于离散和连续值类型，而其他重采样方法只适用于连续数据。
