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Geographic Information Systems

Questions tagged [dem]

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

1,335 questions
info Newest Frequent Votes Active Unanswered
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7 views

Converting IMG to BIL/HRD/BLW?

I'm trying to convert IMG data from USGS's 1/9 arc second DEM to something that Pathloss 5 can read. Is there a way to do so?
0
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1answer
32 views

Can I make a visibility analysis with mask for non visible areas?

I have LIDAR data and I've made a digital elevation model (with all the vàlues). I've made a visibility analysis for 3 buildings with this model: But as you can see in the orthophoto, there are a ...
0
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1answer
27 views

Extract height from DTM into attribute table of point layer [duplicate]

I am using ArcGIS Desktop 10.4 I have an empty point layer (100 random points) and a dtm. I was wondering how I would go about to get the height from the dtm underneath each point into the points ...
0
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0answers
15 views

Whitebox GAT branch depression big raster

I'm trying to run the tool Brunch depression form Whitebox GAT but the process doesn't work probably because the DEM is oversize For generate that raster i converted the single quadrant in the ...
1
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1answer
47 views

Highest point from DEM

I generated the next DEM abd Orthomosaic and I am interested in extract the highest point of each building, is there any workwflow that I could implement in QGIS or SAGAGIS
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0answers
22 views

Filling NoData around bridges in DEM

Is it possible to fill no data around bridges without pixels blurriness (see picture). I use Elevation Void fill function, also tried in qgis No data filling and Grassgis r.fillnulls. I know, that I ...
2
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1answer
48 views

Translating vector by raster DEM data in QGIS?

I'm trying to follow the set of instructions here: https://twitter.com/imhere_asia/status/1023055838787690496 [EDIT] Pasting the instructions here for reference so people can avoid twitter. ...
1
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0answers
28 views

Channel network from high resolution DEM for flat areas

I'm working on channel network extraction from a LiDAR DEM (square grid max resolution 0,25 cm), and my area of study is vary flat with some part below the sea level. I applied the classical valley ...
-3
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0answers
33 views

Delete details from DEM [closed]

I have a DEM or hillshade and I want delete some details from it or delete some pixel value without reducing the resolution. I used reclassify and details disappeared but with 2 classifications. I ...
1
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0answers
52 views

Difference between DEM raster in QGIS 2.18 and 3.4.4 [duplicate]

I came across a really strange problem. Untill today i always worked in QGIS 2.18. Now i wanted to upgraded to 3.4.4 ( it was already downloaded but hadn't used it yet) When opening my QGIS ...
0
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0answers
6 views

Creating 3D Local Scene using pointcloud, DSM, and orthomosaic from Drone in ArcGIS Pro?

I am trying to create a local 3D scene in ArcGIS Pro and display data fro drone flights. I have the orthomosaic from the flight as a .tif, the Digital Surface Model as a .tif, and my pointcloud from ...
2
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0answers
32 views

Problems with DEM exporting after Elevation Void Fill function use

I filled nodata values in DEM by Elevation Void Fill function, everything was ok, but when I exported it, the raster looks different (see picture above), how can I solve this problem? I also tried r....
2
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0answers
43 views

Importing several LiDAR (.las) files in GRASS using v.in.lidar?

I'm building a DEM of a terrain in GRASS and have 48 LiDAR (.las) files. I know I can do this by using r.in.lidar (including the list of files as a .txt) and then r.fillnulls However, I want to ...
0
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0answers
15 views

Assessing mapping accuracy of a DEM with different resolutions

I am mapping conical shaped depressions on the seafloor and would like to know at what resolution of the DEM is my mapping accuracy affected by. For example if I have a DEM of 7 metres, what does the ...
0
votes
1answer
27 views

Clip tool in ArcGIS Pro not working?

I'm trying to clip "Terrain" raster I downloaded from the portal (https://www.arcgis.com/home/item.html?id=58a541efc59545e6b7137f961d7de883) in the shape of a polygon (a country's boundaries) by using ...
1
vote
1answer
52 views

QGIS 3.4 and DEMto3D 2.3 Scaling Error

I'm having a scaling problem when using DEMto3D and extracting STL's for later manipulation. I have a merged TIFF file for Australia and am attempting to extract models of each state so I can print ...
0
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0answers
18 views

QGIS Display Attributes as Z Value for Point Shapefile?

I would like to create a state map that displays a 3D bar chart for each of 20 colleges (mapped as points) showing the percent share of engineering degrees earned by award level (i.e., assoc, ...
3
votes
1answer
135 views

Calculating shadow of trees with DEM in QGIS?

I have a DEM with a good precision (0,5 x 0,5 m/pix LiDAR) and I´m looking for the way to obtain a raster (or shapefile) with the shadow of the trees located in that place for a whole day (ideally ...
0
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0answers
23 views

Change detection using DEMs of difference and error quantification

Im currently working on a project in one of my seminars at university ("Advanced methods in natural hazard research"). We are modelling DEMs with Agisoft Photoscan using pictures from flume ...
1
vote
1answer
38 views

SAGA hydrology toolbox errors

Hi I am having trouble getting the SAGA hydrology toolbox running. Here when I try to fill sinks in the DEM a series of errors are flagged in the log file. This includes for 'select a library', 'DEM' ...
0
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0answers
12 views

DEM colour themes add-in for QGIS [duplicate]

Is there any plugins / add-ins for QGIS that give more of a variety than the default colour ramps?
0
votes
1answer
26 views

Viewshed Analysis for Custom DEM file [closed]

I am new to qgis and trying to do 2 things. My objective is to have an accurate viewshed analysis at the end. But my DEM file is of poor resolution. I do have a shapefile with building height ...
0
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0answers
10 views

Delineated streams not following the Burned streams in ArcSwat delineation

I am using ArcMap 10.2 and ArcSWAT 12.102.19. Even after burning the streams onto the DEM(tried 3 DEMs,CartoSAT 10m,SRTM 90 m,ALOS 30 m), the created reach doesn't follow the burned streams.Why could ...
0
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0answers
16 views

Calculate average slope values for a point using 50ft vector perpendicular to contour

I am trying to calculate the average percent slope of a hillside on either site of a data point. I tried extracting info from a DEM using a radius around the point, but I believe a more accurate ...
0
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0answers
24 views

Creating DEM in GRASS?

I need to create DSM and DEM with resolution 0.4 m. I tried to create DSM with resolution of 1m, everything was ok, but when I set higher resolution, then raster have a stripes with No Data values. ...
0
votes
1answer
57 views

Merging 1m DEM to 30m DEM?

I have a base 30 m.Dem . However, i also have 1m Dem for an area of interest only. I would like to overlay the 1m Dem on the 30 m Dem meaning the area of interest will have 1m and the rest 30m. Is ...
1
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0answers
17 views

Creating Left and Right Image pair to view with 3D goggles in stereo from DEM or Hillshade?

How does one create the stereo pair for viewing in a program such as StereoPhoto Maker? I have processed lidar that I'd like to turn into hillshades and then view in this kind of software, with 3D ...
0
votes
1answer
26 views

Line of Sight Analysis using Points and DEM

I have a DEM and a point feature class with the elevation value from the DEM as an attribute plus with x number of feet added to it representing a tower location. I would like to do a line of sight ...
1
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1answer
60 views

Resampling 0.7 m LiDAR (in raster already) to 10 m DEM in R?

How do I resample the 0.7 m LiDAR to 10 m DEM in R? What are the basic rules for checking the consistency?
0
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0answers
25 views

How to retrieve GIS data in Multiple Orthophoto at point level

I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok. I have different Orthophotos with ...
1
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0answers
41 views

Why is my watershed delineation different- burned DEM vs non burned DEM?

Using ArcMap 10.4, I am trying to capture potential overland flow of farm ponds in a small watershedu. I've followed the typical steps for preparing a DEM for watershed delineation (pit removal, flow ...
1
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0answers
33 views

ALOS/PALSAR High Q DEM 12.5 Accuracy

Does anyone know the XYZ accuracy for the Phased Array L-band Synthetic Aperture Radar (PALSAR) DEMs (12.5 x 12.5 px)? Is there a document for reference?
0
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0answers
10 views

AW3D30: DSM file is grayscale 32 bits?

I downloaded multiple areas in AW3D30, but each time, the DSM file is 32 bit (instead of 16 as indicated in the specs), and the 32 bits are grayscale with the alpha channel always to 255. (I'll be ...
0
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0answers
27 views

How can I change the elevation of a lake on a DEM so I show the lake bottom contours?

I'm studying the drainage of a lake and I have a DEM of the lake and the surrounding area. I already identified the shorelines of ancient lake levels at higher elevations, but I would like to keep ...
0
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0answers
36 views

Erroneous contour polygons in QGIS 3

I have a global DEM and try to calculate contour polygons for 4 different heights in QGIS. In the first image below, you can see the colored DEM (white = lowest; yellow = higher; orange = highest) as ...
0
votes
1answer
75 views

Reclassify and combine rasters in QGIS?

I have a vector layer containing watercourse location which I have rasterized. I also have a DEM containing elevation data for the region in which the watercourses are located. I would like to ...
2
votes
1answer
82 views

QGIS: Edit elevation in DTM to get correct slope of a river

I am new to QGIS and just need it to do a hydrolocic analysis of an area of which I later make a flow model with HEC-RAS 2D. I made it according to this tutorial: https://www.youtube.com/watch?v=Ro-...
0
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0answers
10 views

Creating terrain polygon buffer from line using ArcMap? [duplicate]

I have a line in a steep hill, and need a 400 meter buffer on each side of the line. I know (roughly) how to create buffer on a point, but not a line. Can someone help me here?
2
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2answers
54 views

Mapping coastline geometry with SRTM raster?

Working on a map that includes a bathymetry layer, SRTM data for hillshade, and an accurate coastline boundary edge. I noticed though that the pixel resolution of SRTM 90m resolution creates visible ...
0
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0answers
37 views

Smoothing/denoising DEM to prep for 3D printing?

My DEM was generated from contour lines (as well as break lines and point height data), and the contours persist in the DEM despite doing some basic denoising (although i may not have used the optimal ...
6
votes
0answers
50 views

Coarse Woody Debris extraction

I created very high dense point cloud of some forest plots using terrestrial laser scanner. Then removed points above 1.3 meter to see the coarse woody debris (Fallen dead trees). Attached is the ...
3
votes
3answers
98 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
34 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
votes
1answer
62 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 ...
0
votes
1answer
35 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
vote
2answers
55 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
vote
1answer
67 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
vote
1answer
71 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
votes
0answers
78 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 ...
0
votes
2answers
50 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 ...

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