I want to prepare landslide susceptibility map for a district whose shape is irregular (like in the attached picture) . Does this irregular shape affect in any raster calculations? Or, should I clip a rectangular area within the district and perform the analysis for a rectangular area?
Please help me with this.
Thank you in advance,
Badal Pokharel, Nepal
Dear M. Alvioli,
Thank your for the answer. The references are really helpful.
Regards,
Badal
Could you exemplify what kind of pattern? Format, colors, settlers?
I have prepared inventory for landslides for a whole district (given in Fig 1). I have used factors like slope, aspect ,elevation, geology, landuse, PGA, drainage and thrust for analysis. I am working in 50x50 grid. So, what I am confused in is, should I take a whole area for landslide analysis or clip a rectangular section (Fig 2) within the big area. Does these geometries of district boundary (irregular) and rectangular boundary make any differences in analysis?
M. Alvoli above suggested few papers and that talks about the effective surveyed area for landslides. That helped me to some extent. Please write your thoughts on this. I would be grateful.
Cheers
Badal
Hi Badal, usually we chose the basins within and around the inventory. That's because 1) we want to have all the slopes within the study area, 2) slopes units represent the main feature to investigate, thereby, it represents the main input to extract the watersheds. And then do merging the large basins developed by using on large contribution areas of watersheds. QGIS is efficient to process the steps. (Will email it to you). Best regards.
Hi,
The link below discuss the delineation of watersheds, as a result we consider it as border of proposed study area and that to assure that the slopes are directed inward of the interested areas, as a result, you may merge more than one watersheds to preserve covering the entire inventory.
Watch the video about watersheds extraction(https://youtu.be/vzBzs3zeMyU)
Badal,
The only problem I see is resolution, given small enough resolution you can model any shape with a raster, the problem of extremely high resolutions are ridiculously big datasets. The opposite problem is if you have a very low resolution, your grid may not be able to describe your phenomenon with the desired detail.
If you have the resources (desktop power, disk-space and software), I would tackle the study area as a whole for your landslide analysis, not into little rectangular sub-areas.
I hope that helps.
Miguel.
Dear M. Alvioli,
Thanks a lot for the description and paper. It is very useful.
Regards,
Badal
dear in my opinion it is based on which type of data you will use, and believe Radar data most of data that have been used in research in this field but nowadays the lider became more useful to do this task with high resolution and a perfect representing the landslide susceptibility mapping
My regards
- Badges
- Science topic
- Similar topics
- Geoscience
- Cartography
- Mapping