如何将 GIS 栅格转换为矢量多边形？

Question

如何将栅格 GIS 文件 (tiff) 转为 .json？

Bostock's example 用some JSON data 喂他的D3.geom.contour plugin。但是如何将 GIS 栅格（比如 11px/15px 的 tiff 图像）转换为 JSON。

最终的 .JSON 代码如：[编辑：这不是 topojson 格式]

[
[103,104,104,105,105,106,106,106,107,107,106],
[104,104,105,105,106,106,107,107,107,107,107],
[104,105,105,106,106,107,107,108,108,108,108],
[105,105,106,106,107,107,108,108,109,109,109],
[105,106,106,107,107,108,108,109,109,110,110],
[106,106,107,107,107,108,109,109,110,110,111],
[106,107,107,108,108,108,109,110,110,111,112],
[107,107,108,108,109,109,110,110,112,113,114],
[107,108,108,109,109,110,111,112,114,115,116],
[107,108,109,109,110,110,110,113,115,117,118],
[107,108,109,109,110,110,110,112,115,117,119],
[108,108,109,109,110,110,110,112,115,118,121],
[108,109,109,110,110,111,112,114,117,120,124],
[108,109,110,110,110,113,114,116,119,122,126],
[108,109,110,110,112,115,116,118,122,124,128]
]

注意：.shp 到 .json：已经有a tutorial on how turning shapefiles into lighter topojson，但是在这里没用。

Answer 1

我不认为你可以直接做，它可能是一个几个步骤的过程：

流程

转换.tiff -> .shp

gdal_contour -a elev input.tif output.shp -i 10.0

转换.shp -> .json (topojson)

topojson input.shp -o output.json 

资源

• 注意TopoJSON Command Line；
• Tutorial: Working with Terrain Data in QGIS 指出 GDAL 实用程序；
• gdal_contour 从栅格高程模型构建矢量等高线。