Questions tagged [topography]

The study and mapping of land surfaces, including relief (relative positions and elevations) and the position of natural and constructed features.

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Creating a 3D polygon layered over a DEM

I have a polygon which I have draped over a DEM raster layer so that it has z values matching the terrain underneath it. I now want to turn this polygon into a 3d shape where it is 5 meters tall with ...
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D3.js globe view data visualization

I am using D3.js globe view as in the code penhttps://codepen.io/EleftheriaBatsou/pen/VQxdVY?editors=1000 India map that is in the globe view widget is not same as the one while verifying the globe in ...
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2 votes
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Searching for waterfalls / water drops within an area of interest, return location and height

Is there a system/service for finding or searching waterfalls or "water drop" (say 1.5m drop)? Or is there another (simply) way to gain this data? finding := Input a location and drop ...
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QGIS Print Layout doesn't show elevation labels

I'm trying to export a topographic map with elevation labels, but the Print Layout on QGIS is not showing the labels, only the lines. Why??? EDIT: I thought that was clear enough, but here are some ...
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Level curves in ArcGIS map - elevation - topography

I am using the ArcGIS web map and need to add a contour map (level curves for Uruguay) to perform a topography analysis. I have seen that in the ArcGIS Online search engine there are some maps of this ...
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Choosing Window Operator for 1-D Elevation Data

Have an interesting theoretical question here: Say you have a swath of elevation data that is essentially a line of densely spaced points. The data is noisy, so a simple median filter is something I ...
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Interpreting Ruggedness Index calculated from SRTM Tiles

I am looking for help interpreting the values from Ruggedness Index calculations. I downloaded SRTM tiles using the SRTM Downloader plugin in QGIS. Then I calculated ruggedness from SRTM tiles in QGIS ...
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Identifiying the levels for streams derived from DEM

I am using GRASS GIS and I have been able to identify the various water-flow channels / streams using the documentation from r.watershed. Now I wish to identify the levels of the streams. For example, ...
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Hillshade Settings to Replicate 7.5' Topo Maps (Preset Combinations) using QGIS

I really like the hillshade used in Caltopo 7.5' Topo Maps (Preset Combinations, see attached file for example). Does anyone know what QGIS hillshade settings would reproduce the hillshade used in the ...
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2 votes
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419 views

GeoTIFF height map banding/terracing

I'm getting pretty bad banding, terracing, low resolution appearance when importing height maps to QGIS. I've searched the forums and haven't found a solution to this. Attached are the original USGS (...
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Reproducing terrain ruggedness index from the original paper example [closed]

I am not able to reproduce the terrain ruggedness index for the example used in the original Riley et. al paper. The example is as follows: When I try to reproduce the numbers in MS Excel I get ...
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Where to find topographic basemap with no labels

I am new to QGIS and trying to find a simple topographical basemap for Britain and Ireland. It is a map of prehistoric sites, so I can't have any cities/streets/labels, just topography.
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Georeferencing historic airphotos along constantly-moving section of San Andreas fault?

I'm a geology graduate student working on a master's thesis project in which I'm measuring creep (movement) over time along a section of the San Andreas fault (in California, USA) using SfM derived ...
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1 answer
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Create a topography map base in QGIS

I am building an interactive web bike map and I would like three baselayers. Currently, I have an OpenStreetMap layer and I would like to add a topography layer. I am aiming for something shown on ...
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Elevation profile of earth [closed]

Where can I find elevation data for the entire earth so that for a given location (coordinate) on the earth, I can find out the elevation of that particular location? In particular, I am curious, what ...
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Topography - represent result in WKT as polygons with rings or multipolygon without rings?

I'm new to GIS vector, especially for GIS tools like ArcGIS, QGIS,... My question is, for this image below with poylgon 1 and polygon 2, typically how a WKT (Well-known text) is represented in GIS ...
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Topographic Correction Method for a Single Image SCS+C

I am trying to code the SCS+C topographic correction method for a single image and a I get this error: "Image (Error) Image.constant: Parameter 'value' is required." I have seen a similar ...
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Summarizing flatness of county with statistic Elevation variance per square mile

I need to classify every county in the US as either hilly, moderately hilly, or flat. Accuracy is not critical, just a rough classification. I used R and followed the advice in this answer to import ...
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How could I classify every county in this US as flat, hilly, or moderate? [duplicate]

I'm looking for a VERY rough label for every county, so low-res data is fine here. Is there data on existing elevation change per county? Or should I get an elevation layer of the US and do a zonal ...
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How do we georeference a toposheet using GCS or PCS?

I am new to the GIS domain. I need to georeference a toposheet, Datum - WGS84, 1:50,000 scale map. I have done the georeferencing using WGS for GCP's and then projected to WGS_94_UTM Zone 43N, using ...
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How is Topographic Position Index calculated?

My understanding of how topographic position index is calculated is: TPI = cell value - (mean of cell values within defined neighborhood) But, I see that Weiss' original poster (http://www.jennessent....
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Sentinel-2 topographic artifacts: How to fix?

I'm working with Sentinel-2 (Level2A) false color composite images. A few of them present artifacts in alpine terrain. See highlighted area on the image below, in the Swiss Alps. These artifacts are ...
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Raster not showing on Orthographic projection when zooming out

I am trying to put together Topographic .Tif rasters (from GMTED data) on an ortographic globe on Qgis 3.4.1, for exemple these 8 layers: However when I change the projection and one of the various ...
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Adding elevation point data and lines to topography plot using ggplot2

I have pieced together some code to make a topography plot using elevation data and ggplot2. However, now I would like to overlay onto this plot the country outlines, along with points to show the ...
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How do I assign a height to each individual contour line using QGIS. Raster > Extraction > Contour

What I'm essentially asking is, is there a way to, when making contour lines using extraction in QGIS, assign heights to each line? For example instead of 1000, 2000, 4000, 6000 etc. etc. you have 500,...
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2 votes
1 answer
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Getting from a USGS historical topographic map to a Unity terrain heightmap

Is it possible to start from a USGS historical topographic map and get to a Unity terrain heightmap? To see an example of the kind of historical topo map I am talking about: Go to: https://ngmdb....
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Why does no line appear when using Interpolate Line in ArcMap? [closed]

I'm attempting to make an elevation profile from a DEM in ArcMap using the Interpolate Line tool. I've done this before, and it has worked great--basically I just draw a line with Interpolate Line, ...
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2 votes
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Landsat L1GS product processing to change detection analysis ready state

At high latitude area of Svalbard Norway, one can find Landsat 8 data processed to L1TP level. With previous Landsat missions, this is not the case. Landsat 7 data are processed to L1Gt level and ...
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How to convert DHHN2016 to mean sea level?

I am new to GIS. How can I convert DHHN2016 to mean sea level? I am using this dataset https://www.opengeodata.nrw.de/produkte/geobasis/hm/dgm1_xyz/dgm1_05314000_Bonn_EPSG4647_XYZ.zip which I stiched ...
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What happened to buildings on USGS topo maps?

I have been using the National Map website to download some topographic maps and I can't help noticing a big difference between the old and new. Historical USGS topographic maps have building outlines ...
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Analyzing Sonoma County's topography/slope in 2017 fires

I am looking to create a map of sonoma county's topography. I am looking at one of the components of a fire: slope. I want to first isolate sonoma county, which is easy enough to do, after that ...
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3 votes
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Effectively applying cpt-city colour ramps to elevation in QGIS3

There are lots of nice topography and bathymetry colour ramps provided by cpt-city in QGIS. However, I cannot find a straightforward way of specifying the transition from blue (below sea level) to ...
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Creating seamless/uniform topography with multiple raster tiles?

I have multiple elevation raster tiles of an archaeological site and it would be extremely useful for me to visualize the topography as one 'uniform' image/layer. I have attempted to merge the rasters,...
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Expand features in shapefile

I have a shapefile with 634k features that when I open in QGIS is filtered to 6 squares. How can I expand it to get all the points, I need to make a topo map from it.
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Analysing local features on rasters using ArcGIS Pro?

I have several raster datasets representing the elevation on a beach (See Picture). The beach topography include beach cusps (which represent local max on the beach). I want to extract some ...
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1 vote
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How to make a topographic map with a Digital Terrain Model shapefile?

I'm 2 weeks in self-learning QGIS so I don't know if my question is the same with the suggested similar ones. I'm making a map like this. A map of a mountain with a "mountain-like" texture. By u/...
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Creating a 3D TIN or similar 3D Delaunay triangulation in R

Background: I have topographical datasets with height information as a starting point. The endgame is to create a dataset of triangulations which I can use to import into Parasolid to be used further ...
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6 votes
1 answer
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Finding easiest path to walk on topographic map?

I want to make the shortest path between two points, but the thing is that there's a hill in the middle. I used Naismith's rule to calculate how the slope interfers in the walking time and I did the ...
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2 votes
0 answers
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Seeking method for determining survey points?

I'm trying to write software to create a topographic map, my goal is to select several points of interest and create a minimal mapping that is inclusive of the points and interpolates the topography. ...
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2 votes
1 answer
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Showing Outline of Island on Topographical Contour Map using QGIS?

I am fairly new to GIS. I have been reading through this site and have not quite been able to figure out what I am doing wrong. I am trying to create a contoured topographical map that I can cut ...
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1 vote
1 answer
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Identifying flat-ish hilltops in a DEM?

I am working on a project where I need to identify the area of a hilltop that is relatively flat within which stone structures could be built before the slope becomes too great to build without having ...
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Using GDAL Warp results in odd pixel sizes and gaps

I am mosaicking one meter and three meter rasters to two meters in Python with GDAL Warp using the following code: cl_string = "-of GTiff -co COMPRESS=LZW -tr 2 2 -tap -r near -overwrite \ -multi -wo ...
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QGIS Line between two points based on topography

Is it possible in QGIS to draw a line between two points and take the topography into account? For Example when there's a mountain or a lake between the two points, the line goes around that mountain ...
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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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Calculating Surface Roughness from Land Cover Data/Land Elevation

I'm trying to create a surface roughness file over the continental United States in NetCDF format. I've surface elevation file of 200 meters resolution and land cover data of 30meters resolution. I'm ...
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1 answer
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Locating Basemaps in QGIS?

I've been attempting to download a usable basemap for USGS Topography for quite some time. Going through the USGS procedure to acquire the map has not worked to date. Quickmapservices and Openlayer ...
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2 votes
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Assessing impact of spatial scale on derivative calculations and associated kernel size?

Full question: What is the most appropriate way to assess the impact of spatial scale on derivative calculations associated with typical 3x3 moving window kernel operations? This relates to a couple ...
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3 votes
4 answers
3k views

Combine multiple USGS topo quads into a single seamless raster?

I'm quite new to GIS (so please be patient with my incorrect terminology) but I'm teaching myself as much as I can in order to create my own map of the Boundary Waters Canoe Area in northern Minnesota....
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2 votes
1 answer
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Correctly scale topographic SRTM data in OSM

I am trying to create contour maps in OSM with scales of 1:50,000 and 1:250,000 using 30-meter NASA SRTM data from here. Examples of what I'm trying to achieve can be seen on LINZ NZ Contours 1:50k ...
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5 votes
1 answer
10k views

Assign z values to depth curves in QGIS

I'm new to QGIS and working with GIS in general (student of architecture), so please bear with me. I have obtained shapefiles with topographic curves of an ocean floor. My intention is to export ...
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