Questions tagged [dem]

For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)

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3answers
204 views

DEM of difference - estimate the error - simple method

I have two DEMs of the same area, measured at two different dates. Subtracting one from the other, I can create a DEM of difference (DoD) to find out about the volumetric change in m³. DEM 1 has a ...
1
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0answers
38 views

White grid appears when reprojecting DEM in ArcGIS Desktop?

I am using ArcGIS Desktop 10.5. I have a DEM .tif archive, in WGS 84. The specifics are: Then, I try to reproject it to WGS 84 UTM 19S. Project and transformations -> Raster-> Project Raster I use ...
2
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1answer
87 views

How to Calculate area of LULC at different elevation by using zonal statistics as table tool [closed]

I have to calculate the area of different land classes like forest,barren land etc from my classified land use data at different elevation zones at an interval of 100m. I have DEM of my study area ...
1
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1answer
97 views

Creating DEM from mesh? [duplicate]

I have a mesh ( with points and triangles that define it), and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format). ...
1
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2answers
64 views

How do I combine these two rasters?

I have a raster representing rivers/drainage basins within a terrain: I have a raster DEM of the terrain: In the basin raster, everything in black is 9999. White is nodata. The DEM is obviously a ...
1
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1answer
69 views

How can I use line vectors to alter my DEM?

I'm trying to use vector lines to change the height of the areas of my DEM that they overlay. They trace rivers, and i'm hoping to assign arbitrarily high values to the rivers so that my least-cost ...
1
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1answer
334 views

How do I create a binary mask using Pixel values from a Numpy Array over a certain value (i.e. >1000), in Python [closed]

I would like to create a binary mask using the height values from a Digital Elevation Model, and export this out as a tif. For example, generate a mask for areas over 50m My code so far: from osgeo ...
0
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0answers
84 views

DEM - calculate shortest/easiest path over mountain range [duplicate]

In QGIS, I have a mountain range with a valley on either side (DEM raster file). Is there software or a plugin that allows me to calculate the easiest pathway over the mountain? The answers at Cost ...
1
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2answers
124 views

Getting grid points for DEM purpose that is bounded by surveyor points?

I have a list of surveyor points, and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format). I need the DEM for ...
0
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1answer
51 views

Reclassify with attribute

So, I don't really know how to word what I want to ask, but I took a DEM file and did used the raster calculator to select a certain elevation range. After that I reclassified it to separate it into ...
1
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1answer
84 views

Converting RTK Elevation Data to DEM?

I have a shapefile that contains elevation data. I want to eventually convert this to a slope layer. I'm assuming I have to convert to a raster, then a DEM, then slope. Is that correct? If so, ...
3
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1answer
82 views

Interpreting cell coordinates from DEM?

I'm using Environment Agency DTM LiDAR data which I import into Mathematica in ASCII format to produce ground surface models, sections, etc. The process works fine, but I'm unclear whether the cell ...
0
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0answers
29 views

Interpretation of digital surface model (DSM) built from s2p tool and XML file

I am new to GIS. I am using s2p stereo pipeline to build Digital Surface Model (DSM.tif) from it. The height of certain point in this DSM.tif is 84 meters, and you can see from the color bar on ...
4
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1answer
70 views

Using NAVD88 geoid in Northern Canada?

The USGS NED (1-arcsec) dataset is available for the continental US as well as most of Canada. It is based on the NAVD88 vertical datum. I am interested in using the DEM to orthorectify SAR scenes in ...
0
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1answer
53 views

Image not draping over DEM in ArcScene?

I saw Images not draping onto DEM in ArcScene? but it is different from my issue. I have an image with projection: NAD_1983_StatePlane_Oregon_North_FIPS_3601_Feet. I have a DEM and set the base ...
0
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1answer
98 views

Extracting certain area from DEM using ArcGIS Desktop?

Using ArcGIS Desktop, how do I extract a certain area (uniform 1 km from the entire coastline) from a particular year's DEM image?
2
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1answer
158 views

Error in orthorectification of Radarsat-2 scenes with GDAL and RPC + DEM information

I am trying to use a DEM rational polynomial coefficient (RPC) information to orthorectify radarsat-2 images with GDAL 2.2.1. I have successfully done this with Orbview-3 images using the tutorial ...
2
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1answer
591 views

Why ground model from point cloud in Global Mapper is inaccurate?

I have a LAS file that I assumed was based on LiDAR, but it is actually based on ADS (airborne digital sensor) imagery, according to the body that captured the data. I load the file in to Global ...
2
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2answers
171 views

Seeking for a solution to convert GeoTIFF to 3d WKT

I am trying to convert some DEM in .tif image to polygon geometries representing 3 dimensional triangles that is Well-known text (WKT) - 3D (x, y, z) I was able to use SAGA to convert my GeoTIFF ...
0
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1answer
41 views

DEM to bmp for cnc carving query

I'm importing grayscale elevation images (bmp and jpeg) into a program I use for 3d CNC terrain carving. I've been downloading Hi-Res terrain corrected DEM files from ALOS PALSAR. I bring them into ER ...
1
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1answer
110 views

Combing multiple LAS files with different vertical and horizontal accuracy?

The data set in question was made using .las and .zlas files from respectable sources. Data set 1 was collected in the Fall of 2014. The RAW flight line swath data was processed to create classified ...
0
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1answer
78 views

EU DEM in GRS80 EVRS2000 with geoid EGG08 --> Make it comparable to Black Sea 1975 for Romania

I got contour lines for western Romania in vertical system Black Sea 1975 which is based on elevation data with 100 m resolution. Now I would like to compare that to the EU DEM with higher resolution. ...
4
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1answer
54 views

Seeking algorithms for DEM generation? [closed]

What are the different algorithms employed for the generation of a Digital elevation model from images captured using an unmanned aerial vehicle ?
0
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2answers
112 views

Determining flood extents based on a daily flow? [closed]

I have a DEM raster and daily average flows (e.g., 50Ml/day). And I want to determine how far the water extent goes when the flow accumulates for 7 days based on 50 ml per day?
4
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1answer
155 views

Hack's law for river basins

The hacks law relates the longest stream length with the catchment area of the basin. How can one construct a hack's distribution for a basin and upto what scale the sub basins have to be taken as ...
0
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1answer
37 views

Error in change of projection from Lat/Long to UTM

Why does the the DEM when converted to UTM Zone 43N system give all values as 0 in QGIS? I followed the standard procedure of saving the parent layer and then assigning the CRS. When I open the same ...
2
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1answer
61 views

Working with NaN values in channel network in QGIS?

I have downloaded the conditioned 15s HYDROSHEDS dem of asia and after clipping the desired extent proceeded to evaluate the catchment area. However the next step of channel extraction renders NaN ...
1
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1answer
627 views

Converting GeoTIFF to USGS DEM or DTED using GDAL

I have been looking the documentation for gdal_translate and it doesn't list the -of format available options there. So I tried looking at the source and basically ended up read the SetFromUserInput ...
2
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0answers
58 views

Improving Sentinel 1 Interferometric DSM Accuracy - Removing Surface Anomalies

I have been working through the ASF's "Recipes" for the creation of a DSM from Sentinel 1 (A and B) imagery. I am able to produce a DSM, and am relatively happy with the results in terms of the ...
2
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1answer
106 views

Extracting Road Terrain Properties using DEM / LIDAR

I want to extract following road terrain data from DEM but I'm not sure if its possible. Can i extract these attributes using LIDAR if not DEM ? These are the data fields I need: Horizontal curve ...
-1
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1answer
149 views

SRTM/DEM 1m resolution (batymetri) to point [closed]

I have bathymetry data (1 huge data) = SRTM/DEM/FGDBRaster (0,9818m resolution pixel, floating, 32 bit, 45 GB size) and an alternative data (split into small pieces data) = same data but with 1m ...
0
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1answer
66 views

Origin of LandViewer DEMs?

does anyone know how DEMs that can be downloaded from LandViewer are generated? They have higher resolution than SRTM and other free sources.
1
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1answer
162 views

Determining elevation of a point from a DEM in QGIS?

I have created a series of DEMs that layercake on top of each other. I would like to be able to lookup a coordinate and get the elevation that has already been interpolated. The goal is to ...
0
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4answers
207 views

Have DEM, need polygon outlining region above a certain elevation

I have a DEM in HGT format. I need to isolate all areas above a certain elevation and view them as polygons. Something like this (let's say the pink polygon is everything above 1000m): Seems like ...
1
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1answer
39 views

'Regular Points' vector layer in Bonn

I've downloaded the bonn version of QGIS. Using the 'regular points' vector analysis tool, I've set some 5m regular points over a field so that I can use the x,y coordinates to plot them and measure ...
0
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1answer
60 views

Converting DEM units using Map Algebra and Python

I am trying to write a bit of code that combines a bunch of DEMs that match up perfectly and convert the elevation values of the pixel cells from meters to feet. This is all using Pyscripter and ...
0
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1answer
41 views

Extracting DEM from PRISM data?

I have PRISM data which is in the following format. Are there any ways (software and methods) to extract the DEM or elevation information from these data files?
7
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1answer
488 views

Setting the same min/max for multiple raster layers QGIS

I have 268 hgt-files from Viewfinder Panorama that I'm using to create an elevation model, but each of the files has its own min and max-value in Layer Properties - Symbology - Band Rendering. ...
0
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0answers
44 views

ImageMosaic plugin for DEM rasters on Geoserver

I'm using 30m DEM rasters from the NRCS Data Gateway. I use image mosaic to merge them. But when i preview i see black gaps between rasters. Coverager Parameters: How can i remove that black gaps?
0
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2answers
221 views

DEM from Vector to Raster in GRASS GIS

I am using GRASS GIS 7.4 and I have a DEM as points in a vector format and want to turn it into a raster. I tried using v.to.rast and v.to.rast3, but the elevation is not one of the attributes so am ...
3
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2answers
59 views

QGIS Python Discrete ColorBand Classification

I'm trying to automate a process where we bring in a DEM, extract the contours as a new vector layer, then set the dem to render the band between each contour line a separate colour. I want to do is ...
0
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2answers
54 views

DEM's from Baja, Mexico [closed]

I need to extend my digital elevation map (10m or 30m will do) into Baja from southern CA.
1
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1answer
362 views

Efficient downsampling with GDAL?

I have a 350go GeoTIFF file with DEM data for the entire world. (a mix of SRTM, EUDEM, etc. ...) This TIFF file is tiled with a block size of 256*256. I would like to downsample this file to a lower ...
1
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2answers
109 views

Strange Pattern in LIDAR derived DSM raster

I produced a DSM raster from LIDAR data for eastern Kentucky. There are strange lines from southwest to northeast. Do you have any idea what those might be? I generated the DSM raster with both first ...
7
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1answer
224 views

Can LINESTRING “contain” POINT?

According to Wikipedia, The predicates Contains and Within have subtle aspects to their definition which are contrary to intuition. For example,[10] a line L which is completely contained in the ...
1
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1answer
171 views

QGIS Issue with 3D view altitude binding

I'm running into an issue with the 3D view in QGIS. I have a DEM, which is displaying correctly and a building footprints polygon layer from OSM. It is draping correctly as a 2d polygon on the DEM in ...
2
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0answers
53 views

World DEM speckled outcome solution

I have a world digital elevation model which has been classified into 5 showing the different heights. My issue is that viewing and printing this image as it is results in a speckled look due to the ...
4
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2answers
627 views

Interpolate smoothly nodata values in QGIS

I have a DEM raster where all the buildings have been extruded and now contain "nodata" values. I'd like fill the holes and get a nice and continuous surface (which would approximately correspond to ...
1
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0answers
91 views

Edit a raster (DEM) to create a constant slope angle

I'm trying to edit a raster (DEM) that has square sides (90 degrees) to create a surface with a constant slope angle of 18 degrees. I'm working in QGIS and have not been able to find any help for ...
0
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3answers
75 views

Changing coordinate of point shapefile in ArcGIS using ArcPy? [closed]

I'm working on coding a function in ArcGIS trying to measure the number of pixels between a point (feature class) and its nearest building horizontally within a UDEM raster, then return the number. ...