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Questions tagged [dem]

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

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3
votes
1answer
83 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 ...
1
vote
2answers
128 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 ...
3
votes
3answers
221 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 ...
0
votes
0answers
43 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 ...
4
votes
1answer
73 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 ...
2
votes
1answer
95 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
vote
1answer
94 views

Creating Slope from DEM in ArcGIS Desktop so that information is in feet per mile?

I'm trying to get the Time concentration for the ModClark method in Hec-HMS, and one of the variables is Slope in feet per mile. I have a DEM for the sub basin that I've download, the elevation was ...
3
votes
1answer
3k views

Creating DEM from vector contours using GRASS and R?

I want to convert vector contours to a DEM. From other posts, I wanted to use the Grass r.surf.contours tool. Initially, I converted the vector contour layer to a rasterized contours using the ...
1
vote
0answers
39 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 ...
1
vote
1answer
116 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
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
vote
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 ...
4
votes
3answers
609 views

Merging one DEM into another to fill in missing data using QGIS?

I have a LiDAR dataset with some missing data right in the middle of my map. I would like to use a 5m DEM to fill in the missing areas. Is there a way in QGIS to merge the two but only use the 5m ...
0
votes
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
vote
1answer
408 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 ...
6
votes
3answers
2k views

Burning road network into DEM?

Does anyone have any suggestions for burning a road network into a DEM? I have a Python script written up for this executing this in ArcMap, but I would love to hear if anyone knows of any freely ...
-2
votes
2answers
309 views

Calculating canopy height in ArcGIS Desktop without LiDAR data?

I am currently trying to assess vegetation height for my study area. I am trying to use this guide: http://desktop.arcgis.com/en/arcmap/10.3/manage-data/las-dataset/lidar-solutions-estimating-forest-...
0
votes
1answer
53 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 ...
0
votes
0answers
35 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 ...
0
votes
1answer
65 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 ...
1
vote
1answer
508 views

Error Message Orthorectifying ASTER Imagery in ArcMap 10 with DEM

I am trying to orthorectify ASTER imagery (VNIR, 15m resolution) in ArcMap using an ASTER DEM that I have downloaded from the GDEM website. The area is in the Andes, there are very high elevation ...
4
votes
1answer
10k views

Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?
1
vote
1answer
119 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 ...
2
votes
1answer
174 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 ...
5
votes
1answer
196 views

Calculating limits of visible horizon of location in QGIS?

I am an amateur at GIS. I installed QGIS Las Palmas version in Windows, I searched YouTube and also in Google but I didn't find this question. There is a website that one can input the coordinates of ...
2
votes
2answers
187 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
votes
1answer
45 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 ...
5
votes
1answer
25k views

How to find the number of raster bands?

I have downloaded a 7.5 min DEM . Now while I am trying to mosaic them it gives me an error saying "Input and target dataset should have the same number of bands" . How can I figure out the number of ...
1
vote
1answer
98 views

Counting number of cells which can see each cell in QGIS?

For each cell in a DEM I'd like to count the number of cells which can see it (i.e. direct line of sight). Can anyone explain how to do this in QGIS?
0
votes
1answer
440 views

Data for depth contours/DEM for Mediterranean sea

I am searching for data for depth contours for the Mediterranean sea, especially the Aegean sea in any format (raster, shp). Does anyone know if there are any free available data?
5
votes
2answers
4k views

How to fill holes/missing values in XYZ data / a DEM with QGIS?

I have equidistant XYZ point (text) data that I used to create a point grid. However, it's not perfect - there are some holes. I then created a DSM raster from it, which obviously has the holes too. ...
0
votes
2answers
117 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
votes
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 ?
2
votes
2answers
412 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: ...
4
votes
1answer
158 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 ...
2
votes
1answer
63 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 ...
0
votes
1answer
87 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?
1
vote
1answer
58 views

Importing DEM on MAPublisher?

We exported DEM, point, line and polygon data as .mdb or .gdb formats from ArcGIS. When we import these data to MapInfo, present database and when choosing the data from feature class there is only ...
0
votes
1answer
39 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 ...
1
vote
1answer
715 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
votes
1answer
91 views

Intersecting to vector layers when there is no common attribute [duplicate]

I am trying to join two vector layers into one, the first is a road noise barrier shapefile, the second is a vectorised DEM. The road barriers have a relative height attribute for each section of ...
2
votes
1answer
114 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 ...
2
votes
0answers
64 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 ...
18
votes
5answers
7k views

Splitting raster into smaller chunks using GDAL?

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
1
vote
1answer
184 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 ...
1
vote
3answers
1k views

Exporting slope raster for entire country in GEE

I have loaded SRTM (30m resolution) DEM data through Google Earth Engine and have determined the slope for the entire country of Peru. When I export the image out into Google Drive, I get the ...
0
votes
4answers
216 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
vote
1answer
574 views

Wrong values when merging raster files

I am trying to merge several (70 at least) raster files (a digital elevation model, ASTER DEM v2). I am using QGIS and I use the tool "Raster > Miscellaneous > Merge". I works well and I get the new ...
-1
votes
1answer
154 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
votes
1answer
67 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.