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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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27 views

Free GPS data (x, y, z) of an agricultural field

for a project at the university I need GPS coordinates of an agricultural field. I know, the longitude and latitude are trivial, but I'm especially interested in height values. Is there any source, ...
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1answer
38 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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32 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 ...
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3answers
108 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
90 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
424 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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0answers
59 views

Creating buffer using DEM in ArcMap?

I would like to create a buffer around a point taking into account the topography. From what I understood so far, I should use Path Distance tool with my point as source location, nothing in cost ...
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1answer
64 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
106 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
49 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 ...
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1answer
195 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
821 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
35 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
505 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
701 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
937 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
214 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
140 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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1answer
520 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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0answers
66 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 ...
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1answer
124 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
109 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 ...
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2answers
502 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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274 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 ...
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2answers
190 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
117 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
171 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
115 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
128 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 ...
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1answer
301 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
77 views

Automatic vectorization of toposheets

I have a survey of India toposheet in TIFF format. Is there a way to automatically vectorize it into feature classes? I'm using ArcGIS 10.3.1.
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0answers
228 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 ...
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1answer
101 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 ? ...
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1answer
81 views

Querying the National Resources Canada Toporama WMS

I have the server URL (http://ows.geobase.ca/wms/geobase_en) but no idea what is the query format for the tiles. As an example, this is the URL for the USA Topo maps served by ArcGIS, where [Z]/[Y]/[...
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41 views

Elevation from GPS Vs. Query Elevation from Static TOPO database like SRTM

As far as I understand the GPS determines Elevation by real time calculations. What I don't understand is how? For example let's assume perfect (errors free) Lat/Lon fix by GPS. So I can query static ...
3
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1answer
294 views

How big is the error of relative elevation between two points taken from GPS relative to taken from a topographic survey?

I am sufficiently familiar with the fact that a GPS is not supposed to be used to measure elevation of a point, since it gives the elevations relative to a reference ellipsoid, not relative to MSL of ...
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1answer
2k views

How to create a crisp topographical/terrain map with ggplot2?

I am trying to produce a high quality vector based map (in greyshades) in order to report locations. I tried this by getting maps from GADM and SRTM to make a raster as a base for plotting in ...
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0answers
92 views

Finding unnamed Antarctic peaks using QGIS? [duplicate]

I'm a complete novice at GIS. My project is to find the highest peaks in each Antarctic territory, and compare the results with the international gazetteer to find which peaks are and aren't named. I'...
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0answers
83 views

How to do regression analysis in SAGA for topographic correction

Currently I am trying to do the topographic correction using C-Correction. I would like to know if there is a way to do the regression analysis between L (uncorrected reflectance of each band from ...
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1answer
244 views

How to Find Local Lowest Point(s) on a Landform?

I am trying to write a code to find the local lowest points using Python. This approach will be applied to raster landform data such as digital elevation models. What approach can I take to find the ...
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0answers
56 views

Location of island “Trinidad”?

I was reading a travel diary of an ancestor of mine who describes a cruise from Hamburg to Natal (South Africa) in 1860. At one point a rock island named Trinidad (supposedly only inhabited by animals)...
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0answers
26 views

Infinite length lines coming off polygons in shapefile

I have been sent some OS MasterMap topography area shapefiles. (OS MasterMap is a national map product including pretty much every permanent structure and land parcel.) A few of the polygons in each ...
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1answer
92 views

Placing coordinates on a topographic map [closed]

I am using QGIS for the first time. I want a topographic map with coordinates of locations. I have the SRTM data for the area of my interest. Using the following link I am able to get the topographic ...
3
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1answer
150 views

Seamlessly merging USGS DEM data with higher resolution survey?

I have a 10m USGS DEM for my entire map extent (~100sq miles) Inside of that, I have specific regions of higher quality GPS point data. (From a rover using a OPUS corrected RTK base station) How do ...
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1answer
315 views

calculating volume

I need to calculate removed material volume on arcmap 10.2. I have a present-day dem and a very large and irregular polygonal shapefile that is the area in which I have to calculate volume. How can I ...
2
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0answers
316 views

How to calculate Fractal dimension from DEM [closed]

I have a digital elevation model of a sea floor topography, and I have already creat TIN, shp, ras of this zone (only X, Y, Z(depth)) To calculate the topography complexity, I think fractal dimension ...
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0answers
69 views

Plot GPX on topographic map with no labels

I am trying to plot a path from a GPX file on a topographic map with as few labels as possible. I've played around with a handful of both online and desktop solutions, but it seems that I either don't ...
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0answers
364 views

Negative reflectance values after topographic corrections (cosine correction and modified Minnaert correction)

I am trying to manually correct the surface reflectance values of some Landsat 7 and 8 images. I'm using Minnaert modified method, which uses the cosine correction as one of its inputs (see below the ...
2
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1answer
588 views

Positive Topographic Openness - do any FOSS tools (other than SAGA) provide this?

I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS) Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a ...
11
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3answers
768 views

Calculating sunrise/sunset time while considering topography

I want to calculate the sunrise and sunset times for a full year for a given location taking topography into account. Perhaps sunrise/sunset are not the right terms, but what I want is the time at ...