转载自HiGIS.cn:http://www.higis.cn/
Label Vs. Annotation
** 标注label **
是图层的属性，保存在图层文件里
1、标注的内容
2、标注的样式
3、标注的位置
4、其他设置（eg:可见比例尺）
5、标注的分类显示： a. 对数据分类
b. 对每一类分别标注
特点：
1、标注的内容及位置均与数据关联
2、标注的操作只能针对整体，而不能针对单个标注进行
3、标注的效率（显示速度）低，因为它是动态显示，每次操作都重新计算一遍
** 注记annotation **
a.是数据，保存在数据库中
b.或是地图元素，保存在地图文档*.mxd中
Tags: GIS
用途: 从field name 查找field index
说明原文:
FindField Method
Finds the index of the named field in the fields collection.
Syntax
object.FindField (Name )
The FindField method syntax has the following object qualifier and arguments:
| Part | Description |
|---|---|
| object | An object expression that evaluates to an object in the Applies To list. |
| Name | Required. A string expression that represents the Name. |
Return Value
Long
Product Availability
Remarks
Tags: GIS
通过ArcSDE打开一张Feature表DLTB_H_320982100，所对应的F表是F93，所对应的S表是S93 看如下情况：
1.在ArcMap中通过ArcSDE加载该图层的全部数据，以下SQL是通过Oracle后台抓的
Select /*+ FULL (F_) */ F_.fid,F_.numofpts,F_.entity,F_.points,F_.rowid
FROM DF.F93 F_
Tags: GIS
Feature的常用的绘制方法包括：1.简单绘制；2.唯一值绘制/多字段唯一值绘制；3.点密度/多字段点密度绘制；4.数据分级绘制；5.质量图(饼图/直方图)； 6.按比例尺渲染；7.比例符号渲染。
1.简单渲染
简单渲染是ArcEngine的默认渲染，我们打开一个FeatureClass，建立一个FeatureLayer的时候，如果没有给FeatureLayer设置Renderer那么使用的就是简单渲染。简单渲染对整个图层中的所有Feature使用同一种方式显示。简单渲染在ArcEngine中用ISimpleRenderer来表示，ISimpleRenderer的使用方式如下：
//假设layer是一个IFeatureLayer，获取IGeoFeatureLayer
Tags: GIS
About DEMs
A DEM is a digital elevation model. It can be used in ArcView's Spatial Analyst, Model Builder, and 3-D Analyst extensions. To read up more about DEMs, go to the USGS National Spatial Data Clearinghouse DEM web site.
DEM Sources for Texas
TNRIS serves the 1996 Digital Elevation Models at 30 meter pixel resolution - see the TNRIS Digital Data-DEMs site for more information. DEMs at TNRIS are identified by their USGS Quad Map name - see the USGS Quad and Quarterquad Locator Map to know which DEM you will need. DEM data from TNRIS is in USGS DEM format.
Unzip the file (it will have a name like 3097420g.zip) and you should see a new set of files. The file that ends in .dem is the actual digital elevation model in USGS format (e.g., 3097420g.dem)
Important information! The TNRIS DEMs are usually in the UTM coordinate system, NAD 27, Zone 14 for most of central Texas, and map units (x,y horizontal units) are meters. Some of the elevation data in these DEMs is in meters and some is in feet. It is very important that you know which! Once you bring up the data, examine it in ArcMap to determine this if possible.
Other DEM sources
DEM data is available from the Federal government in SDTS format, and from many state agencies.
Importing a USGS format DEM in ArcGIS
Note: The following instructions will only work if you DEM is in USGS format. Most DEMs from the USGS are not in USGS format (go figure...) - it is in SDTS format (but the USGS is also now producing DEMs in other formats including ArcGrid). If your DEM is in SDTS format (Spatial Data Transfer Standard), you will need to use the Import SDTS Raster to Grid tool in ArcToolbox.
After you download the DEM, you need to unzip it. Once it is unzipped, you can import it into ArcGIS.
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Start ArcToolbox, and choose Conversion Tools - Import to Raster - DEM to Grid. Read the Help information before you begin, then follow the instructions.
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The USGS DEM is the file that ends in .dem (e.g., 3097420g.dem)
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Leave all the defaults as they are for now - we will talk about these in class.
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For output grid, you can navigate to your personal folder and type in a new name - this will be the final ESRI formatted DEM that you will work with, so give it a good name, like the name of the quad map it represents (e.g., austin_west). But read this carefully - you cannot specify a folder that has spaces in the folder name; in fact, no folder in the entire path on the computer can have spaces in it (don't ask me why). So the folder path to this new grid needs to be something like C:\temp\edwards_group\dem\austin_west
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Once the importing process is done, take a look at the results in file manager or explorer - notice that there are now two folders, one called the name that you gave the grid (e.g., austin_west) and one called info. This is an ArcInfo formatted GIS data set.
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Next add the new grid to a data frame in ArcMap.
Using a DEM in ArcGIS
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To use a DEM in ArcGIS, you need the Spatial Analyst extension. In ArcMap, go to Tools - Extensions and make sure that Spatial Analyst is checkmarked.
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Next, choose View - Toolbars and turn on the Spatial Analyst toolbar.
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To create a hillshade map once your DEM is in view, click on the Spatial Analyst toolbar and choose Surface Analysis - Hillshade. Accept the default settings first, then try again and play around with the settings. Be default, this will create a temporary file. If you want to create a permanent file, click on the Output Raster section, navigate to your personal folder , and give the hillshade file a new name.
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To create a slope map, you can use the Surface Analysis - Slope command. Beware, your horizontal map units must be the same unit as your elevation units (e.g., both feet or both meters) - often they are in different units, in which case you need to do some additional preparation! See Working with x, y, and z units in Digital Elevation Models for details and instructions.
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If you need to re-project the grid to a different coordinate system, ArcToolbox has projection tools for grids under the Data Management area. The define projection wizard for grids is different than for shape files, and a little trickier. The necessary parameters are: the projection is UTM, zone 14, meters, no x,y shift, and the datum is NAD 1927 US Nadcon
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For more information about Spatial Analyst, go to ArcGIS Desktop Help or the digital manual, Using ArcGIS Spatial Analyst.
Tags: GIS
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