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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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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Planchon & Darboux depression filling algorithm - Meaning of epsilon

I hope this is the correct place to ask this, but while trying to understand (and implement) the Planchon & Darboux depression filling algorithm, I came across a bit in the pseudo code I do not ...
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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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35 views

Add elevation point data and lines to topography plot using ggplot2

Hopefully this is a simple query. 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,...
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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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1answer
50 views

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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Select Channel Network within QGIS

I have created a Channel Network polyline shapefile from the Channel Network tool in QGIS. I now need to select any channel routes which flow through the red polygon as shown below. The attribute ...
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OSM topographical tiles with no labels or human features?

I'm looking for Open Street Map topographical tiles with no labels. I've gone through all the Basemaps based on this: https://ipyleaflet.readthedocs.io/en/latest/api_reference/basemaps.html I need ...
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43 views

Why does no line appear when using Interpolate Line in ArcMap?

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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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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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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Interpolating Line in ArcGIS 3D Analyst

I am trying to make a 2D topographic profile using the Interpolate Line tool and a DEM. I've done this before on a different project; not sure why it's not working now. The 3D Analyst extension is ...
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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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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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1answer
107 views

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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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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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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1answer
100 views

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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83 views

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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1answer
99 views

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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Seeking contour (topo) lines for United States?

I can find five foot contours for most areas, where can I find 1 foot or 2 foot contour lines? Prefer ArcGIS or AutoCAD but will take anything I can get.
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405 views

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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1answer
124 views

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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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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4answers
1k 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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1answer
175 views

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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1answer
4k 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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172 views

Adding topography to base maps using Surfer?

I want to add the topography map with extension (BLN) to my the map which I create it using the Surfer prog, I put only the country board. How can I add the topography maps as a background using the ...
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223 views

Client-side 3D surface generation in ArcGIS JS API

Is there any way to create some sort of 3D surface (mesh, TIN, elevationLayer) from contour lines on the client side with ArcGIS JS API? Or alternatively edit a hosted 3D surface (any format)? In our ...
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Getting the area of a polygon from Google Earth or .xyz digital elevation model INCLUDING area due to topography

I'm doing some analysis for a study on geomorphology. For this I'm comparing the 'bumpiness' of lava fields to the 'bumpiness' of the surroundings. What I'm trying to do for this is measure the ratio ...
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1answer
442 views

Looking for topographic map of Bogota, Colombia, with elevation contour lines [closed]

I'm looking for a topographic map of Bogota, Colombia; specifically, we want to get the elevation contour lines, and export that layer to CAD. If anyone knows of any free places to find this data, we ...
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1answer
3k views

MGRS grid in QGIS

I'm trying to generate a Military Grid Reference System (MGRS) grid on QGIS (with polygons in scale of 100m), such a grid will be similar to when importing a grid made of shapefiles (such as http://...
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1answer
37 views

Historic Topo Sources

Middle of a project, wondering if there is a better historic topo source than TheNationalMap for finding historical maps for an area. Coring some lakes, would be nice to know that they've been there ...
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1answer
2k views

Finding height for a point in QGIS

How can I find the height in for a given topographic point in QGIS?
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1answer
2k views

Find the GPS coordinates where two boundary lines intersect

I have a detailed topo map for an irregular shaped property. It has boundary lines expressed like this, for example; S76˚45'08"W and S59˚38'24"W. The map also notes how long each boundary line is. I ...
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2answers
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Create a 3D topographic map with locations marked on the map using R

I am currently trying to create an interactive 3D surface plot using plotly in R. My dataset includes a matrix of Latitude and Longitude and I have a DEM for the region I would like to make this ...
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1answer
333 views

What is the meaning of this linear scale of angles on this 1951 map of Iceland from the U. S. Army Map Service (AMS C762)?

On the U.S. Army Map Service (AMS C762) 1:50,000 maps made of Iceland 1948–1951, there is a scale marking at the top which shows degrees, I suspect angles. In the image below it shows 25°–29°. It ...
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2answers
328 views

QGIS color polygon according to points

I have two layers. Layer 1 contains points (x,y) and layer 2 contains one polygon. All points in layer 1 are positioned within the polygon of layer 2. The points in layer 1 contain an attribute with ...
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1k views

Generate Height Above the Nearest Drainage (HAND) using QGIS

I have a DEM I want to generate a HAND for and want to do so in QGIS. Does anyone know of any plugins or the processing steps to be able to do this?
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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 ...
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342 views

Setting extent while interpolating in ArcGIS Desktop?

I have a set of lines representing level curves. I have also a polygon. I want to interpolate them for creating a hypsometric map. I use the Topo to Raster command but the problem is that even if I ...
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Solutions for generating grade/slope estimate heatmaps from a topography contour layer

Given a shapefile layer of 5-ft interval topography contour lines overlaid on google earth, I could, using the Ruler tool and some simple arithmetic, calculate average percentage grade numbers for a ...