There are papers mostly with 30 m x30 m DEM. Also, I have experienced that the influence of a class within a landslide conditioning factor varies on the basis of resolution. How should we deal on this?
Hi Badal,
Generally, better resolution, better accuracy. Here's a link for 12.5m DEM from ALOS PALSAR, which is also free. Under dataset, check ALOS PALSAR and download Hi-Res terrain corrected data. It's better than 30*30 data.
Link:
https://vertex.daac.asf.alaska.edu/
Good luck!
Kaushal
Badal Pokharel You can also use (if possible) DInSAR data for generating very high resolution DEM, which can be used for making landslide susceptibility map. PSInSAR is also a very good technique to generate DEM with very high resolution, but it needs data stacks.
Dr. Kaushal,
How does better resolution give better accuracy? I don't believe.
I agree with 𝗠. 𝗔𝗹𝘃𝗶𝗼𝗹𝗶. DEM resolution matters, of course, but the use of very high resolution DEMs can be counterproductive. It has, let's say, to match the scale of observation/analysis.
Thank you 𝗠. 𝗔𝗹𝘃𝗶𝗼𝗹𝗶 for the discussion and paper. & Thank you 𝗔𝗻𝗮𝗻𝘁𝗮 Man Singh Pradhan. Previously, I used a too general expression, thank you for the correction. Indeed, there is an optimal DEM resolution based on multiple criteria. 𝗠. 𝗔𝗹𝘃𝗶𝗼𝗹𝗶 's work is very nice:Article Optimizing landslide susceptibility zonation: Effects of DEM...
In addition to it, I came across another interesting article worth sharing.
Article Effect of raster resolution and polygon-conversion algorithm...
Much depends on your what you are mapping. Many landslide features, or indicators of instability can only be seen with high resolution lidar - especially in densely vegetated terrain, where tree canopies are larger than the diagnostic features required for identifying your landslide or unstable polygon. This is especially true for low gradient landslides, that can be completely undetectable with a coarser DEM. On the other hand high res DEMs can be misused. For example, if you are trying to answer a landscape level or meso or macroscale question, such as whether your landslides occur on north or south-facing slopes, you absolutely do not want to use a high res DEM. In this case a high res DEM will produce too much noise.
Dear Badal Pokharel,
The resolution of DEM is highly affect the result of susceptibility. However, that doesn't mean very high-resolution DEM can produce a very accurate result. In the literature, various resolutions have been used based on the availability of DEM but I think the resolution should be less than 5 meter.
This article presents the current state of knowledge regarding the generating of high resolution DEMs. Fine-resolution (several points per m2) topographic data collection technologies are presented and compared. DEM errors and the methods used to remove them are then highlighted and discussed@Badal Pokharel
High resolution can give better results but it depends on your techniques and the expertise. ALOS PALSAR 12.5 is free DEM.
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