Questions tagged [aspect]
The compass direction that a topographic slope faces, usually measured in degrees from north.
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Mean aspect of polygons based on DTM file in ArcGIS Pro
I need to calculate the mean aspect of a number of polygons in a shapefile.
I have a DTM (guess it's a raster?) file that I already used to calculate the aspect of 20x20 pixels in my area of interest, ...
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Make a slope-aspect map and create a circular legend for it in QGIS
I'm working on Terrain analysis of my ROI and could compute aspect and slope separately. Although I found a fairly easy tutorial on how to make a slope-aspect raster, I want to know if it's possible ...
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Combine Slope and Aspect of a DEM for suitiable PV-Powerplants
I want to get areas for PV-Powerplants via QGIS.
I used the solution under Filter for south pointing areas from a DEM for extraction of the areas which are not facing north (60-300°).
But I need ...
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Filter for south pointing areas from a DEM
I want to get all south pointing areas within a city. These will be the ideal locations for PV-Plants.
I am aware that a DEM is rasterdata and there is not an attribut table like for shape files/...
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Distort buffer on slope direction in QGIS [closed]
I'm an archaeologist and an average QGIS user, not advanced at all.
I'm studying a method for the mountain archaeological contexts. My aim is to define some influence areas around the sites and ...
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Determine the cardinal direction of a polyline
For a research project, I need to determine the cardinal direction of a polyline shoreline. For this, I would like to divide the coastline into 200 m sections, so that the cardinal direction is the ...
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How to calculate exact slope and aspect for a polygon
I want to calculate the aspect and slope for polygons, because they appear as fruit-growing areas.
I got the DEM 1m for my datas and calculated aspect and slope with the QGIS functions. Then I ...
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Plotting NDVI vs ASPECT in Google Earth Engine
I tried to plot the values of NDVI against the ASPECT. but I'm getting the following error.
Error:
1. Array (Error) Reducer.toList, argument 'tupleSize': Invalid type.
Expected type: Integer. ...
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Creating lines from aspect value
I have a shapefile that contains multiple agricultural stand information. One of the columns is the mean aspect value of the stands. I need to draw lines using the mean aspect value of the stands. Is ...
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Create raster of aspect relative to the nearest road
I know that slopes which are downhill from the nearest road are an important raster layer for my model (example application: cars carry seeds on their wheels. The seeds fall on the road and downhill ...
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Error calculating aspect from DEM in R using raster/terra
I have a DEM file gathered using R. The raster and terra packages both have a function to calculate aspect, called terrain(). When using the terrain() function and the units="degrees" ...
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Join adjacent polygons based on aspect values only when "look each other" [closed]
I have a map with polygons that represent the average of aspect for a certain slope of a mountain region. I'm looking for a way to merge only adjacent polygons that "look to each other", ...
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Correct measure unity for slope and aspect in order to work in QGIS with "r.sun.insoltime"
I'm using QGIS 3.10 and I should create a raster that shows the hours of sunlight referring to a given day for my province. r.sun.insoltime (Fig. 1, sorry it's in Italian but I traslate) to work asks ...
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Correct format for slope and aspect in order to work in QGIS with "r.sun.insoltime" [closed]
I'm using QGIS 3.10 and I should create a raster that shows the hours of sunlight referring to a given day for my province. r.sun.insoltime (Fig. 1, sorry it's in Italian but I traslate) to work asks ...
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Aspect function creates blank file [duplicate]
I am trying to make get aspect from an elevation file but the code keeps making a blank file
import arcpy, os
from arcpy import env
from arcpy.sa import *
env.overwriteOutput = True
elevation = r&...
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Aspect function creating empty raster using ArcPy
I am trying to derive the aspect from an elevation file. When I run the function it creates a new file but the file is empty. my code:
import arcpy, os
from arcpy import env
from arcpy.sa import *
env....
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An error occurred when using the terrain function in the production of Shiny dashboard
I am new to the 'shiny' package. I just try to produce an aspect map from the existing DEM data using the Shiny dashboard for training purposes. However, I faced the below warning in R and error in ...
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Calculate aspect for stream segments in R from 2D linestring and DEM
I would like to calculate the general aspect for stream segments in R. The stream network has been derived from the DEM and is in 2D. I have split the stream segments into equal parts of 100m (or less)...
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Using Aspect tool in QGIS
For my bachelor thesis in biology I´m working with QGIS 3.14 (Pi) and tried to create a layer where the slope aspect/expositon/exposure is presented. I´ve got a DTM1 on hands. There is this function ...
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Terrain aspect similarity
I have a point data set with terrain aspect at the location of the points, measured in degrees. I want to compute the similarity of aspect between the points, e.g. 70° is similar to 90°. This is ...
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Using WCS DEM data for make slope and aspect maps in QGIS [duplicate]
I need to do several slope and aspect analyses (hundreds).
Instead of downloading an ASCII for each location, I want to extract/clip the elevation data from wcs and do the analysis.
This is the WCS ...
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Define point locations in relation to slope [closed]
I have a dataset of settlements that I would like to put in relation with slope and aspect layers that I have made to see if there is a preferred altitude or direction (facing north or south, etc.) ...
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How to find all cells within a neighborhood with slopes towards the center?
I would like to iteratively go through each cell in a raster in arcGIS that meets criteria (already established as per below description) and find the percentage of cells in a several km neighborhood ...
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Wrong values while aspect calculation
Trying to calculate aspect for south direction of my DEM. In this manual it is explained how to do it for nothern direction. But when I'm trying to use the expression of this type for southern:
"...
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Create line feature from aspect value in ArcGIS
I'm investigating the danger of rockfalls into lakes in mountainous areas by using the hydrological tools of ArcGIS 10.7. My problem is that rockfalls don't exactly behave as surface runoff would.
...
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QGIS Raster Mask Layer?
I have a raster slope layer and a raster aspect layer. The slope layer is single band grey, that is black to white, with white as the steepest slope. The aspect layer is pseudo colour.
I'd like to ...
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Identifying slopes surrounding a lake (in ArcGIS)
I'm working with ArcGIS 10.7 to investigate lakes in the mountains. I have created a 2km "hazard buffer" around every lake-TIN showing instable slopes (>40°) above the lake surface from where a ...
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Obtaining slope and aspect for points in QGIS
I'm new to QGIS.
I have GPS points uploaded to QGIS and a ⅓ arc-second DEM (USGS) of the area. I'd like to generate slope and aspect data for each point.
What is the best way to do this?
The ...
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Slope and Aspect calculations giving wildly different results based on zoom using Leaflet
I asked Accessing slope and aspect data using Leaflet? last week about getting slope and aspect as a function of lat and lng in leaflet, and I am in the process of trying to code out a good answer. ...
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How to reclass zero values for an aspect raster layer
reclass in QGIS 3.4.11 to reclassify a raster file of aspect values. All cells reclass apart from zero values which now show as 'no data'. Text file is as follows:
0 thru 23 = 2
23 thru 68 = 2
68 ...
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Accessing slope and aspect data using Leaflet?
I am building an application in leaflet, and I need to be able to access slope and aspect as a function of latitude and longitude. Currently I am able to get elevation data from the mapbox elevation ...
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Extracting slope of aspect information using QGIS?
In What is SOA (slope of aspect)? @Spacedman explained to me what SOA means. Now I need help to understand how I could work with it and extract the data that I want.
I want to use Qgis (with Grass ...
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What is SOA (slope of aspect)?
I’m reading an article that the authors talk about extracting values of SOA (slope of aspect). I can’t find anything related to that on Google.
This article reference is : ZHOU, Yi et al. Automatic ...
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Google Earth Engine, how to distinguish between rivers/streams and ponds/lakes in a water mask
I am trying to pull out every lake and pond in a region of SW Alaska. I have successfully identified all water features using the following code:
// study area
var rect = ee.Geometry.Rectangle([-168, ...
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Why is my aspect not displaying the full data?
I am trying to get the slope aspect for the altitude shown above. Can someone please advise me on why this may not be working properly?
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Calculating area of pixles for certain Aspect value per specific area?
I am using ArcGIS 10.6. I have the aspect (raster file) for the roof of buildings at the city scale. Now I want to calculate the area of each aspect group per building. I tied zonal statistics, zonal ...
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Selecting a subset of a raster, based on aspect and slope, as input to calculate area
Background
I created some digital elevation models and subsequently made a 2 layer raster for each containing the calculated aspect and slope using raster::terrain. Now I want to calculate the area of ...
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Conditional Statement (CASE-WHEN) in QGIS for slope aspect
After processing a DEM with a mask to get the aspect values of some polygons I would like to create a new field classifying those values as N, NE, E, SE, S, SW, W, NW.
I've written this but I can't ...
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Reading cell values of Aspect map using ArcPy? [closed]
I have generated an aspect map from a DEM using ArcGIS and I want to create a CSV file containing the cell values using the arcpy library. I have done reading raster maps using the arcpy library ...
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Why North direction is shown in red color on aspect maps?
I have been recently exposed to an aspect map that looked like this:
I wonder why North-y orientations (N, NE, NW) are shown in red and orange while South-y orientations (S, SE, SW) are shown in ...
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Corine data aspect analysis in ArcGIS
I have a SRTM dataset, Corine Land Cover and have already calculated aspect.
I want to know the relative proportions of exposition classes of certain landcover type.
My thought was to use zonal ...
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Calculating slope and aspect from DTM lidar elevation data in ArcGIS Desktop? [closed]
I have an ASCII 2m lidar DTM file which I converted into a raster in ArcGIS with the From ASCII to Raster tool. From this DTM file I would like to calculate the slope and aspect. I have used the ...
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Calculating an "overarching" slope and aspect for each polygon of a feature class
I have a feature class containing polygons and an associated raster with elevation data. I'm looking to calculate a single slope and aspect for each polygon within the feature class. I don't want a ...
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Using Overlay Analysis (e.g., Union) with point data (point shapefile)?
Is it possible to compare a point shapefile with a DEM raster in which the Aspect tool has been applied?
I am reading about Overlay Analysis but cannot find a definitive answer.
The attached photo ...
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Selecting south-facing slopes with slope > 10° using ArcGIS Desktop?
I have to make a Model in the Model Builder which will select the areas with slope bigger than 10° and which are facing to the south. It should be used for environmentalist who will just insert a DEM ...
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Erratic results from filters.normal in PDAL?
Given this roof structure:
I get the following output for the normalx, after using:
{
"type":"filters.normal",
"knn":8
},
(orange to purple : -1 to 1)
Comparable situation for ...
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What is the difference between Aspect and Flow Direction tools?
There are two seemingly identical Spatial Analysis tools:
(1) Surface -> Aspect:
Derives aspect from a raster surface. The aspect identifies the
downslope direction of the maximum rate of change ...
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ENVI files (datafile +hdrfile) not displaying properly in python
I am trying to topographically correct my already atmospherically and radiometrically corrected images. To do so I need to calculate illumination conditions at the time of image acquisition. Terms in ...
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Methods in Slope, Aspect SAGA calculations
Using this algorithm in QGIS I can choose between 7 methods, the default one being by Zevenbergen & Thorne 1987. What's the difference between them and can I just use the default one without ...
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Understanding aspect units in QGIS
I created an aspect raster form a DEM raster in QGIS 2.14, and got this results:
I know that the results refer to degree units , but still i don't understand how to read the map result- i mean to ...
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