Questions tagged [dem]

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

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34 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
58 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 ...
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1answer
501 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
50 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
92 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 ...
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1answer
140 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 ...
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1answer
64 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
134 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 ...
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4answers
180 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
37 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 ...
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1answer
59 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 ...
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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
437 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. ...
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0answers
42 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?
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2answers
187 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 ...
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2answers
53 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 ...
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2answers
50 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.
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1answer
293 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 ...
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2answers
104 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
212 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 ...
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1answer
151 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
51 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
529 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 ...
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0answers
83 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 ...
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3answers
74 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. ...
3
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1answer
416 views

Alternatives to cesium terrain builder?

Looks like cesium-terrain-builder still have this issue and can't be used for large projects, so I wonder if there any alternatives to cesium-terrain-builder that can produce DEM tiles, can work with ...
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1answer
555 views

DEM reconditioning?

I'm using ArcGIS Desktop 10.5 Arc Hydro Toolbox & encountered a problem while trying to delineate watersheds respectively drainage lines. The red lines indicate my obtained drainage lines, which ...
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0answers
354 views

Rasterio Raster merge - horrible result

I am merging .DEM files from CUGIR NY repository, and need to merge files into one larger image for the whole of NY city. I use python 3.6 + rasterio; It works perfectly for all but one file - "The ...
2
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2answers
50 views

Flatten broad area through road fill connecting upstream and downstream

What are some recommended approaches for flattening a broad area through a road, as a means of connecting the upstream and downstream parts of a stream bed? I am not trying to connect these areas for ...
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0answers
79 views

How can I merge a DEM mosaic with an overlapping bathymetry raster (while keeping only the portions of each that I want)?

I am tasked with merging a bathymetry raster with a mosaic raster I created from ArcGrid DEM Tiles downloaded from the National Map, for an areal extent spanning the Coastal Lowlands Aquifer System. ...
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0answers
161 views

Shapefile with data into Unity?

So far I have imported my GeoTIFF as a height map (raw) into unity. The simplest solution to getting the road map shapefile on was to set it up as a PNG texture and layer it on. This worked well, BUT ...
2
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2answers
302 views

Usage of interpolation methods with DEMs: Linear vs. natural neighbors

Using the ArcGIS tool "TIN to Raster" (3D Analyst Tools --> Conversion --> From TIN) to work on my Digital Elevation Model I was wondering about the interpolation methods. I can choose either or: ...
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0answers
16 views

Points on the opposing side of a breakline

If you have a breakline or even a single line segment within a DEM, how can you tell if two points lie on the opposing side of that breakline or line segment? From a computational geometry standpoint ...
1
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1answer
372 views

GeoTiff import appears to be flat in BlenderGIS

I an very new to GIS and I am trying to import a GeoTiff file into Blender to view it as a model before importing into unity. For some reason when I import the file into blender as a raw DEM it ...
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1answer
359 views

How to open .hgts file from NASADEM data

I have the NASA SRTM1 data as .hgt files from their ftp website, but I would have these elevation data in respect to WGS84. I found by NASA's ftp site a folder named srtmOnly that contains what I want,...
1
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1answer
88 views

Find intersection of multiple DSM's using Python and GDAL

I am quite a beginner in respect to GIS and hopefully someone can help me out with the problem I have. I have multiple digital surface models [DSMs] of the same area with all necessary geo-...
2
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0answers
53 views

Adaptive raster to points sampling based on change of slope in QGIS?

I have a high resolution elevation map and need to convert it to XYZ points. Simple conversion generates a lot of points in flat / constant slope areas which are redundant for 3D terrain generation. ...
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1answer
543 views

Using Color Ramp Manager Plugin in QGIS?

I followed instructions mentioned here and installed the Color Ramp Manager by choosing install experimental plugins as well. Now, when I go to Properties > Style > Single Band PsuedoColor and I ...
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1answer
75 views

Saving NDVI TIFF file as txt file in ArcGIS Desktop?

I have to use elevation data (dem.tif) and NDVI data (ndvi.tif) as covariates for regression kriging and I want both these files as txt files. How do I do this?
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0answers
13 views

Mosaic multiple slope files

I am trying to mosaic multiple slope files into one large slope file. What is the best tool to use? I have tried mosaic to new raster but the values change from multiple decimal points to whole ...
1
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1answer
78 views

Generalizing slope raster in Mapinfo?

I am working on calculating a slope raster in Mapinfo using a 15cm DEM derived from a LiDAR point cloud and the output data will have 3 predefined breaks displayed so I need to blur those relatively ...
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0answers
574 views

Openlayers in QGIS - Errors in opening google satellite/

End goal: To put contour lines with lat&long layers from a google earth location (Rock Piles beach, HI) in QGIS. I plan to use CRS: EPSG:3760 Does the Plug in (Openlayers / QuickMapServices) ...
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0answers
25 views

Reduce or heighten a DTM with overlaying polygons

I am using QGIS 3.01. I have a DTM over a historic area. There has been done archaeological surveys there, which suggest that the ground was several meteres below todays surface many hundred years ...
1
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1answer
331 views

cesium quantized mesh generator

We are trying to develop pur own quantized mesh generator and visualize these terrain tiles on CesiumJS. As an input we use SRTM data that belongs to north parth of TURKEY. We generate contours on DEM,...
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1answer
139 views

Changing DEM resolution when creating a slope raster? [duplicate]

I want to create a slope map using a LiDAR DEM. I think that I should use the slope tool; but I need a slope map with a 2m resolution and I'm not sure how to do that. How can I have a slope map with ...
1
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1answer
138 views

Blocky Raster from TIN. How to increase resolution?

So i am trying to create a seamless DEM using a DTM created in pix4d with a 5cm resolution (Raster). I have then collected RTK bathymetric data which i have turned into a TIN below To create a ...
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1answer
75 views

Elevation shading of linear feature compared to surrounding ground level in QGIS

I have a digital elevation model (DEM - geoTIFF) in QGIS 3.2. There is a linear feature (earth bund/wall) in the DEM that I would like to shade/colour based on its elevation above the surrounding ...
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0answers
18 views

Adding small-extent rasters to DEM

My goal: create viewsheds for observers which also incorporate the heights of buildings which could block observer view. This is using archaeological data, and is representing time change -- so I need ...
0
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0answers
148 views

Generate XYZ coordinates of DEM mesh/grid

Is there a way to generate a wire grid of plain text XYZ coordinates starting and ending points for each wire segment? I want to generate them from a digital elevation model. Preferably with gdal/qgis ...
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0answers
37 views

Obtaining a smoothed DTM?

I am use AcGIS 10.1 and have a DTM with an 8 m grid resolution. Which tool could I apply to smooth the surface?