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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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1answer
43 views

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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28 views

Calculating Relative Position Index (RPI) using ArcMap

Does anyone know how to calculate RPI - Relative position index in ArcMap (similar to TPI - Topographic Position Index)? It's needed for calculation of improved TWI - Topographic Wetness Index.
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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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0answers
44 views

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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22 views

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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28 views

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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0answers
41 views

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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0answers
31 views

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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0answers
70 views

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/...
2
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1answer
63 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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0answers
91 views

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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0answers
32 views

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
71 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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1answer
68 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
60 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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37 views

Create rotated rectangular map excerpt with local coordinate system from GeoTIFF

I work with numerical boundary layer/weather prediction models and simulate flow over topography (Areas below 100sqkm). As an input it takes topography as raster data, e.g. 400 cells in y and 600 ...
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0answers
55 views

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 ...
2
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0answers
58 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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1answer
41 views

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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0answers
294 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
88 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 ...
2
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0answers
48 views

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 ...
3
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3answers
877 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....
2
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1answer
157 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 ...
3
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1answer
3k 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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1answer
140 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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2answers
185 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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0answers
85 views

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 ...
0
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1answer
386 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
2k 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://...
2
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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
1k 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
1k 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 ...
6
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2answers
2k views

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 ...
14
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1answer
297 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 ...
2
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2answers
249 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 ...
4
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2answers
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?
2
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0answers
80 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 ...
1
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1answer
286 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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0answers
185 views

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 ...
2
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2answers
887 views

Creating a map highlighting areas of potential visibility of a high structure

The end goal is to add a point which will represent a mast/pylon of x height and for QGIS to generate polygons for the surrounding area which will have direct visibility of the top of the structure ...
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0answers
355 views

How to do topographic correction of Landsat 8 image in ERDAS?

I am trying to perform a topographic correction of a Landsat 8 image using the C method described in the paper below. I am doing this in ERDAS IMAGINE Spatial Modeler. However, I am not sure how to ...
4
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2answers
293 views

Determining best neighbourhood search radius for Topographic Position Index (TPI) for predictive soil mapping?

I'm not sure how to determine the best input values for a search radius to create a TPI for the purpose of predictive soil mapping. Would this depend on the spatial extent of the area I wish to map?...
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1answer
241 views

How to fix unusual initial DEM input values and derivative raster output values in SAGA GIS without rescaling?

I am trying to run elevation derivative tools on a provincial DEM provided by the Ontario Government website (Ministry of Natural Resources and Forestry) and I am getting strange values when bringing ...
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1answer
336 views

Raster appears smooth when created but pixelated when opened again

I have a set of xyz points that I want to turn into a raster format for bathymetry. I am using the Topo to Raster (3D analyst) tool and using the depth as the Field and PointElevation as they Type. ...
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0answers
221 views

Buffering based on topography in ArcGIS Desktop?

I need to do a buffer based on the real terrain. Like 500 meters from a polyline on all sides. I have DEM (SRTM) of the terrain. Is there a way to do that?
2
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1answer
262 views

How would I determine my search radius when conducting a Topographic Position Index in SAGA GIS?

When running the TPI tool in SAGA, I get this parameter-entry window: Under the section highlighted in the red box, what do these parameters mean? Do the search/neighbourhood grouping parameters mean ...
0
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1answer
440 views

Creating Topographic Position Index in SAGA GIS?

I am trying to create a TPI from a DEM tiff file in SAGA but keep getting the following result: I'm just not sure what I'm doing wrong.
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0answers
381 views

Solar radiation analysis with ArcGIS Desktop 10.4 [closed]

I'm not an expert in GIS, I learnt it recently, and I'm trying to improve my skills. I'm trying to calculate the loss of solar radiation at a specific point due to surrounding topography. I'm ...
1
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1answer
222 views

Topographicmap.jpg convert to GPS readable [closed]

I have topographic map 1:25000 and I want that map to be GPS readable. So, is there any program for maps that can import this .jpg extension and to track my position in platform of this my topo map ? ...