Questions tagged [elevation]

The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).

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153 views

Use DEM elevation attributes in vector polygon?

I am modeling glacier retreat scatching polygons on DEM surface trying to come out with 3D scatch. Is it possible to adjust "height" of polygon to follow elevation of DEM surface (eg. glacier height ...
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52 views

Checking and enforcing downstream Z constraint for synthetic streams?

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data. The stream features are in a Z and M enabled polyline ...
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Which STRM resolution Srtm2Osm.exe uses?

The piece of program Srtm2Osm uses SRTM elevation model from NASA to produce countour lines in OSM format. Does it use the SRTM1 at 30m or SRTM3 at 90m?
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225 views

Elevation statistics for a given Area

I am attempting to determine the best way to calculate the Minimum and Maximum elevation for a defined area. The area is defined by an IPolygon The elevation is defined as an ISurface Possible ...
2
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0answers
63 views

Elevation Profiles Using QGIS vs. Google Earth

I have several routes I am calculating elevation stats for. What I want is Total Ascent/Cumulative Gain, where all ascents and descents are accounted for. As opposed to solely the difference between ...
2
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0answers
21 views

HGT Elevation vs Calculated Elevation

I wondering how to interpret the elevation calculation. Per example. We are in Canada and I use SRTM3 files. I use the GDAL library to extract my elevation, everyting is ok, except: Why (or how) the ...
2
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0answers
51 views

Converting .gri to topojson

I am making client-end javascript-powered maps in the context of web development. I am not using gdal, which I gather is a special kind of rendering software. Data source site: http://www.diva-gis....
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0answers
93 views

Complex 3D/elevation profiles in ArcMap 10.6

I'm looking to create a more informative 3D Profile than appears possible with vanilla Arc tools. Honestly I'm kinda surprised that this doesn't exist, maybe I'm searching the wrong terms. Situation: ...
2
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0answers
81 views

Selecting raster pixels based on dem range

I have two raster layers that are equal extent and resolution: one that is qualified as nonforest tree cover that is made up of pixels with either the value of 1 or NA, and one DEM. What I am hoping ...
2
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0answers
57 views

Converting Surface Model to Elevation Model?

Is there a way to convert a digital surface model (DSM) to a digital elevation model (DEM) in QGIS? Surface models contain lots of noise (e.g. trees, buildings) when I only want to show the ground. ...
2
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0answers
216 views

How to change the vertical datum of a geotiff DEM

I am trying to do some change detection between SFM derived DEM products, but the DEM i would like to use as my base elevation (and one other) is in NAD83, the remainder are WGS84. I would like to ...
2
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0answers
208 views

GDAL merge of DEM data resulting in large black tiles, elevation min/max problem?

I am new to QGIS (former Arc user) and having trouble with the raster merge tool. I am merging 7 tiles of SRTM arc 1 data to cover a province in eastern Ecuador. Data is resulting in large areas of ...
2
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1answer
197 views

Georeferencing X Y (AND Z) with GCPs in QGIS

I have GCPs recorded to centimeter precision in lat, long, and elevation. I want to georeference my UAV-photogrammetry-generated GeoTIFF and DEM with these GCPs (since the GPS on my UAV is only ...
2
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0answers
77 views

Align approximately colocated vector points for comparison

I have a more general, methodological question and do not have much knowledge about GIS techniques. I have 6 topographic survey ([x,y,z] point clouds), each representing the same dune/beach system ...
2
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0answers
761 views

Correcting incorrect altitudes of points recorded by my Android or how to calculate Geoid Height in QGIS

I tried to edit my question with more details and I also think that lot of people can benefit from this question! I was recording a track with my Android and later I found out that I end up having ...
2
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0answers
549 views

How to calculate elevation of the point?

I have two points: A ( x1 ( latitude ), y1 ( longitude ), z1 ( elevation ) ) and B ( x2, y2, z2 ). x1,y1,z1 and x2,y2 are known, also I know the distance between A and B. How can I calculate z2 ...
2
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0answers
313 views

Postgis Geo Elevation Raster: Get average Elevation

I am running Postgresql 9.5.5 with Postgis 2.2.1 on Ubuntu. I have imported ASTER GDEM elevation information as a raster and query it for elevation using geo coordinates. Currently I use ...
2
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0answers
277 views

DSM and buildings height

How can I create a Digital Surface Model in order to collect the height of buildings and what's exactly needed to create a Digital Surface Model? Any software provide creating it (ENVI or PCI ...
2
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0answers
336 views

How to show a 2.5D surface of raster above terrain layer in Cesium?

I'm developing an web application that will show surfaces of rasters and terrain. These rasters are on GeoTiff format. I learned from example cesium can show image overlays earth surface. The ...
2
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0answers
48 views

Does USGS 3DEP data use a hash or checksum?

I'm downloading some USGS 3DEP elevation data, e.g., the file at the following URL: https://www.sciencebase.gov/catalog/item/563afea8e4b0d6133fe7357b The "ID" of this file is given in both the URL ...
2
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1answer
411 views

QGIS estimate height of feature vertices from TIN

I have a TIN representing a digital terrain model, and another polygon layer representing features (e.g. building outlines) which is assumed to 'sit' on top of the DTM. How do I calculate the ...
2
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0answers
189 views

How to get the most accurate elevation reading for the ground floor of a building?

I am looking into a way to calculate the elevation of the ground floor of many buildings in a study area. My plan is to run the building centroids against an elevation grid to get an elevation ...
2
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0answers
168 views

How to create buffers having regard to topography with QGIS

I want to create buffers of 25 kilometers around points in a point-shapefile with QGIS. My problem is that I don't need an air-line distance of 25 km around the points, but a "real distance" having ...
2
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0answers
376 views

High-level method for offline future road elevation data

I am new to GIS, so please do not hesitate to call me out in providing limited information. I have a .tiff Terrain (elevation) data file for the east coast of the US and a .osm.pbf OSM file for ...
2
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0answers
313 views

From track+waypoints to elevation profile with waypoints

I have a track and waypoints (1) imported in QGIS. I want to calculate the closest point from every waypoint to the track (2). Then, I want a table with data that allows me to draw an elevation ...
2
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0answers
535 views

Generate contour lines for big DEMs and import into PostGis

I've downloaded the SRTM DEM files for most of Europe, from both 3arc_v4.1 and 1arc_v3 versions. The first comes in 5x5 degrees tiles, the latter in 1x1. I can stitch them together with gdalbuildvrt ...
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0answers
48 views

infer the altitude from a DTM & finally provide it to point / evincere la altitudine da un DTM & finalmente fornirla a dei punti

I would like to complete a point vector's table with Z data. I am not able to take Z coordinate from a dtm (downloaded from http://www.regione.piemonte.it/geoscaweb/index.php?pgs2=0&pgs3=DTM10&...
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0answers
3k views

Find Average Elevation - ArcGIS Desktop

I am working with 2 shapefiles. One contains the boundaries of a city, the other contains polylines representing the topographic features of the area. Essentially, the polylines make a topographic map....
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0answers
214 views

Where do I find official summit elevations found on USGS topo maps?

I'm creating topo maps for my day hikes guides for national parks. I've already done one for Glacier National Park. When I was working on summits, I downloaded the data for Montana from GNIS and when ...
2
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0answers
306 views

Inverting color ramp in legend

I have inverted the color ramp to display land surface elevation, now when I add a legend in print composer it shows the lowest value at the top and the highest at the bottom. See below: It is more ...
2
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0answers
1k views

DTM Extraction/Smoothing in ArcGIS

I have an .las file, intended to be a DTM (bare earth) that I generated from a photogrammetry software package that has come out just a bit too lumpy. I now have the license for that software tied up ...
2
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0answers
457 views

Global height data as polygons — Natural Earth doesn't have it?

I love the bathymetry data from Natural Earth. I've been looking for the last few days for the same basic data but for land. I'm trying to find general elevation shapefiles, as polygons. I don't need ...
2
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0answers
374 views

Read negative elevation data from NASA png tiles

I query NASA JPL service using query string. Response is a unsigned 16 bit per pixel png image and the values are elevation values in meters. Same is described in the capabilty xml of the layer as can ...
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0answers
32 views

Cross section profile distance not providing accurate distances?

I have created a DEM file, which I am using to draw a cross section along a line to see the variation of height from point A to point B along land seen below. When it use the Profile tool on the ...
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0answers
51 views

Filling in holes in heightmap with lower resolution heightmaps?

I have this elevation map of the Verdal area in Norway, from the Norwegian mapping authority. The first one has a 1m resolution, but has some holes in the data. I'd like to fill in those holes with ...
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0answers
38 views

Combining Bathymetric and Elevation Data using R?

Here is some elevation data of some islands. I wish to add depth info to the water. With the generous help of @Spacedman at Overlaying elevation data and bathymetry data in R? I get: To resolve the ...
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0answers
24 views

New York buildings - XYZ altitude map

I am looking for a source of buildings elevation, preferably stored as 2D images (for each pixel, the intensity corresponds to the altitude in that XY). Considering the case of NY, it would be a XY ...
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0answers
197 views

Band 1: Access window out of range in RasterIO()

I'm trying to implement a mouse_move event handler to display the elevation based on the mouse location. I'm using the ThinkGeo API to display the raster map (.tif) and gdal C# to get the elevation ...
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0answers
75 views

Extracting raster values to point feature class failing in ArcMap?

I need to extract values to point features from Mosaic dataset made out of DEMs (Whole world SRTM) . My feature class has 18,000,00 points. When I ran the below tools, only <20K points receive ...
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0answers
175 views

QGIS - Lookup elevation or slope from geoTIFF from a series of lat/lon values

I have a geoTIFF file (pretty large) covering a good chunk of Spain around Almeria. I got it from the EU-DEM v1.1 data (25m resolution), freely available in which I have a route in lat/long and I want ...
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0answers
156 views

Locate roads that are close to steep slopes which risks landslides

I've a query, I'm trying to locate all the roads which are basically at risk of erosion (landslide?) when it's raining heavily for a municipality. What I have to work with is this: A shape layer ...
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0answers
92 views

QGIS .adf file saved as GTiff changes elevations

I have got two .adf DEMs which I need in GTiff format so they can be merged. When I 'Save As' the layer as a GTiff, the resulting output has elevations which are inconsistent with the original .adf ...
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0answers
64 views

Creating a polygon that shows the specific elevation above a river using a DEM

My goal is to determine the possible area covered by interpreted Tertiary drainages. To keep my example simple, I have a DEM and a River polyline. I would like to see the area a polygon (or raster) ...
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0answers
54 views

ArcGIS Elevation and Z Coordinate

I have standalone application (ArcObjects C# 10.3) uses axSceneControl, I'm trying to get a mouse click point: private void M_axSceneControl_MouseDown(object sender, ...
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0answers
542 views

DWG/DXF conversion to DEM file

I have got a detailed CAD drawing (DWG format) showing a house plan and topographic survey. I want to use the heights from the topo survey to create a digital elevation map in QGIS. I have tried a ...
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0answers
198 views

Co-registration of two DEM raster

I have 2 different elevation files, a ALOS GDSM elevation set & a DSM extracted from Corona imagery. Since the Corona file has some inevitable offsets (mainly in z, non-systematic across the area ...
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0answers
107 views

AGOL “Elevation Layer (Hosted)” is not displaying outside of a narrow scale range

28/08/17 Edit: Solved. None of the errors or tools will specify this, but you need to manually generate pyramid layers on the input raster to have it display correctly as an elevation surface. ...
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0answers
395 views

Reading SRTM30 Plus data with Python

From How to extract elevation from .HGT file? I know how to get the elevation from SRTM1 and SRTM3 files. But how to get elevation from SRTM30 Plus ftp://topex.ucsd.edu/pub/srtm30_plus/srtm30/data/ ? ...
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0answers
63 views

Deriving Topographic Information from Geotagged Photos?

I wish to extract elevation data from geotagged photos? I have worked with DEM's and the open source CLI program: GMT for my graduate studies. I own a DJI Phantom 3 and used the trial version of ...
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0answers
235 views

Obtain elevation from a request lat,long with a map .tif

I am trying to get the elevation between two points in a route of Spain using APIs with HTTP request. I am using OpenStreetMap to get the routes, but I don't know how extract elevation with other tool....