As of May 31, 2023, we have updated our Code of Conduct.

# Questions tagged [tpi]

The tag has no usage guidance.

8 questions
Filter by
Sorted by
Tagged with
1 vote
32 views

### TPI calculation by PDAL [closed]

Is there a convenient way to calculate the topographic position index by PDAL? I have LAS file and what I do is iteratively for every point calculate the TPI. The coordinate information I take from ...
79 views

### Calculate TPI for irregular DEM

When I use SAGA's Tool Topographic Position Index (TPI) or Tool TPI Based Landform Classification (in QGIS or SAGA itself) on a rectangular DEM the results are as expected but when I try them on a DEM ...
• 369
60 views

### quite different results in spatialEco::tpi with circular and rectangular window

In R, I have an elevation raster. I want to calculate the topogographic position index using the spatialEco::tpi function. The CRS of the elevation raster is "+init=epsg:5677"; the CRS unit ...
• 1,041
317 views

### Stripes in TPI from SRTM 30 DEM

The TPI is calculated with a 150 to 300m annulus in Google Earth Engine. The underlying Elevation-Data from SRTM does not show such striped. I did use raw SRTM from GEE for elevation, no reprojecting ...
866 views

### Using SAGA GIS for TPI classification?

I processed one country with TPI, and I got a certain Landforms classification of terrain. (Topographic Position Index (TPI) calculation as proposed by Guisan et al. (1999)). When I processed only one ...
• 2,385
328 views

### How to merge pixel values to the nearest maximum value based on area in a classified raster?

We have a raster image with 9 discrete values. Generated the image using SAGA's Terrain Analysis -> Morphometry -> TPI classification technique. Now, like to merge pixels which occupy certain area (...
• 1,421
3k views

### How to conduct logistic regression between two rasters [closed]

I have two rasters. The first raster is a region showing sinkholes(depressions) of the region(cell values are 1 for sinkholes and 0 for non-sinkhole cells). The second raster is the TPI(Topographic ...
• 241
1 vote
662 views

### Will Topographic Position Index (Tpi) not work in scattered raster layers?

I have a non-continuous elevation raster layer and want to use tpi in the spatialEco package in R. The elevation raster is in EPSG:5677 and looks like this: I always get this (to me) rather cryptic ...
• 1,041