Topojson:如何在GIS软件中设计有效的多边形，线，点? [英] Topojson: How to design valid polygons, lines, points in GIS softwares?
问题描述
到目前为止，我一直使用Web上的GIS文件，这些文件为我提供了管理多边形，河流，陆地等.然后，我将其转换为Topojson格式，以提供D3js.
Up to now I always used GIS files from the web, which provide me administrative polygons, rivers, landmasses, etc. I then convert them to Topojson format to feed D3js.
今天，我必须在Quantum GIS(QGIS)中设计自己的图层(wine_areas).同样，此.shp文件稍后将转换为Topojson格式.
Today I have to design my own layer (wine_areas) within Quantum GIS (QGIS). Similarly, this .shp file will later on be converted into Topojson format.
在GIS软件(.shp文件)中设计形状，线，点时:我应该担心的关键方面是什么，以及如何做..shp和最终的Topojson文件是有效的，具有预期的类型?通常，相邻的多边形共享其共同的弧形，等等.
When designing my shapes, lines, dots within a GIS software (.shp file): What are the critical aspects I should worry about, and how to do so the .shp and the final Topojson files is valid, with the expected typologies ? Mostly, with neighbor polygons sharing their common arcs, etc.
我特别想知道如何在GIS软件中设计我的topojson"arcs":
I especially wonder how to design my topojson "arcs" in GIS softwares :
- 我应该把形状放在附近吗，例如
[][] - 我应该设计形状并用线
[|]进行切割吗?
- 需要哪种精度? (以及如何知道)
- should I put my shapes nearby such
[][] - should I design a shape and cut it with a line
[|] - which level of precision is needed ? (and how to know it)
和其他技巧.
推荐答案
在QGIS中:
-
转到设置> 捕捉选项，选中底部的两个框，然后选中要处理的图层左侧的框.设置一个大于0的公差.我喜欢设置一个以像素为单位的公差，并使其足够大，以使顶点折断时将很明显. 10px对我来说很好.
Go to Settings > Snapping Options, check both boxes at the bottom, and check the box to the left of the layer(s) you're working on. Set a tolerance greater than 0. I like to set a tolerance in pixels, and make it big enough that it will be obvious when a vertex has snapped. 10px works well for me.
使用拓扑检查器插件(使用插件> 管理和安装插件... 启用)来查看您是否有任何空白或重叠之处.安装后，使用 Vector >访问拓扑检查器.在弹出的面板上点击配置，然后在第一个框中选择您的图层.在第二个框中，选择必须不重叠，然后单击添加规则，然后对必须不具有无效的几何形状进行重复.根据您的设计，您可能还希望一定不能有差距
Use the Topology Checker plugin (enable with Plugins > Manage and Install Plugins...) to see if you have any gaps or overlaps where you don't intend. Once installed, access with Vector > Topology Checker. Hit Configure on the panel that pops up and select your layer in the first box. In the second box, select must not have overlaps and click Add Rule, then repeat for must not have invalid geometries. Depending on your design, you may also want must not have gaps
在设计数据时，可以将图形彼此相邻绘制，而不是先绘制然后拆分.在TopoJSON中要让要素共享弧的任何地方，请确保形成弧的顶点对齐在一起. Shapefile不会保存拓扑，但是对齐在一起的两个顶点将具有相同的坐标，并且拓扑将由TopoJSON实用程序推断.
When designing your data, you can draw shapes next to each other, rather than drawing and then splitting. Anywhere that you want features to share an arc in the TopoJSON, be sure that the vertices forming that arc snap together. Shapefiles do not save topology, but two vertices snapped together will have the same coordinates and the topology will be inferred by the TopoJSON utility.
关于所需的精度，TopoJSON量化点，您可以调整此值. 此处解释，知道多少需要一些数学运算.如果您获得的点足够接近以至于它们被量化到同一点，则无需担心会发生冲动.
As for how much precision is required, TopoJSON quantizes points, and you can adjust this value. Knowing how much requires some math, explained here. You don't need to worry about snapping if you get points close enough that they are quantized to the same point.
已经写了所有这些，我现在才意识到这个问题有多老了...
Having written all that, I just now realized how old this question is...
这篇关于Topojson:如何在GIS软件中设计有效的多边形，线，点?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
