nsw_lidar
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nsw_lidar [2019/02/23 08:37] – bushwalking | nsw_lidar [2020/09/09 20:36] – [Resources] allchin09 | ||
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====== Resources ====== | ====== Resources ====== | ||
* [[https:// | * [[https:// | ||
- | * [[http:// | + | * [[http:// |
====== Topographic maps ====== | ====== Topographic maps ====== | ||
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The NSW DEM data is supplied in 2km squares. The squares need to be merged into a single DEM for further operations. | The NSW DEM data is supplied in 2km squares. The squares need to be merged into a single DEM for further operations. | ||
- | While this can be done in theory using a virtual raster, I have had poor performance with this. Any operation seems to result in screen redrawing, so moving around | + | Most of the eastern ranges, where a lot of bushwalking happens, are 2m DEMs. The coast is typically 1m, and the western slopes |
- | Instead, I generally use the the Raster- > Miscellaneous -> Merge... function | + | ==== Virtual Raster ==== |
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+ | While merging can be done in theory using a Virtual Raster (Raster- > Miscellaneous -> Build Virtual Raster... ), I have had poor performance with this (including recent version 3.12 Bucuresti). Any operation seems to result in screen redrawing, so moving around and zooming in and out is slow and painful. | ||
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+ | That said, if you are just using the Virtual Raster for future steps, then the limitations from the screen redrawing may not be important. | ||
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+ | QGIS uses [[https:// | ||
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+ | ==== Merge Raster ==== | ||
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+ | I generally use the the Raster- > Miscellaneous -> Merge... function | ||
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+ | QGIS uses [[https:// | ||
===== Fill Sinks ===== | ===== Fill Sinks ===== | ||
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Run v.clean: Cleaning Tool = rmdangle, Threshold = 5,10 | Run v.clean: Cleaning Tool = rmdangle, Threshold = 5,10 | ||
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+ | ===== Dumping Ground / WIP ===== | ||
+ | ==== Resources ==== | ||
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+ | [[https:// | ||
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+ | [[https:// | ||
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+ | [[https:// | ||
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+ | [[http:// | ||
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+ | [[https:// | ||
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+ | [[https:// | ||
+ | ==== Method ==== | ||
+ | The below snip of Breakfast Creek makes use of TPI calculated from a LIDAR derived DEM. Only positive values for TPI as displayed, which indicate cliff-like features. It is then combined with contours and aerial imagery to convey the terrain of the area. | ||
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+ | {{: | ||
nsw_lidar.txt · Last modified: 2024/04/05 19:00 by bushwalking