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What is the step-by-step process to solve Angle = ArcCos(R / R+h)?

I'm attempting to calculate the angle to the horizon from various heights to determine how much of the Earth's curve should actually be observable; however, every example and website I've seen that ...
John Mathews's user avatar
0 votes
1 answer
198 views

Reclassifying a Curvature raster

I am trying to reclassify a profile curvature raster generated by the Curvature tool available in ArcGIS into three classes following the tool help where it is reported that; ...a negative value ...
Dave's user avatar
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0 answers
52 views

Creating large extruded polygon which follows Earth's curvature using ArcGIS Pro

I am trying to create a shapefile of a large ocean volume for manipulating some CMIP6 data. I am currently approaching this by defining a polygon in ArcGIS Pro, and then extruding this is a negative Z ...
RuthChapman's user avatar
-1 votes
1 answer
37 views

Vector line length vs. geographical distance (as a bird flies) [closed]

Is there a way to compare the length of a line (ESRI Shapefile in my case) to the actual distance it covers with freely available tools? I am developing an optional path algorithm. The image below ...
Kristjan Sander's user avatar
0 votes
0 answers
417 views

Plan curvature in QGIS

I am trying to obtain plan curvature from a DEM. So far I have tried two methods from SAGA and GrassGIS plugins, however both do not seem to work and give errors. Do you have a workaround suggestion? ...
mn5hk's user avatar
  • 31
3 votes
0 answers
183 views

How does grass r.viewshed take into account the Earth curvature?

Up to now I always had to do such analysis in a local Cartesian Coordinate System and on relatively small datasets, but today, I want to compute a viewshed analysis on a large raster DEM which is ...
swiss_knight's user avatar
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0 votes
0 answers
78 views

Squaring up photo into Google Earth using spatial adjustment

I have a photo such as: that I want to add into a Google Earth map. I know where the image must be: North: 44°16'48.00"N, South: 35°15'0.00"N, East: 4°42'0.00"E, West: 10°1'12.00&...
Joan Carles Montero Jiménez's user avatar
2 votes
0 answers
40 views

Converting river mile points into a polyline that closely matches the curvature of the stream

I have a dataset of river miles for all the rivers in Oregon. I am particularly interested in the estuaries on the west coast of Oregon, as I would like to compare sinuosity of the portions of the ...
kgardner's user avatar
1 vote
1 answer
1k views

Why does size of circle object drawn in Google Maps increase when moving it away from Equator

I'm building a web app that allows the user to search the database based on his Google Maps location and a customizable search area around the location. I've noticed that when I keep the radius of the ...
Maurice's user avatar
  • 213
0 votes
2 answers
1k views

QGIS visualisation of the flat earth

For a project, I try to visualize an image of the world map in QGIs print layout. However, in QGIS, the round earth is flattened in a 2-D flat map. How can I include the curving of the earth, so that ...
Shaun van Kersbergen's user avatar
2 votes
1 answer
96 views

How to warp 3D model to take into account horizon curvature?

I am using USGS Astrogeology data for the Moon's south pole. Here's the same dataset at half resolution: "LRO_LOLA_DEM_SPolar875_10m.tif (tif) 278 MB" on this page. I already have a process for ...
CourageousPotato's user avatar
0 votes
0 answers
477 views

Making grid files (minimum curvature) from point data in QGIS?

Is there any way to make a grid file from point data (shape file) in QGIS? I mean by grid a colored raster file like Geosoft .grd or ERMAPPER .ers file or like. Minimum curvature would be ...
Estiivan's user avatar
  • 397
3 votes
2 answers
778 views

Find radius of curve?

Using QGIS with GRASS I have found a route through r.drain but it has many sharp curve. the maximum radius of curve allowed to me is 176m. Is there any to reduce the curve sharpness to 176m or at ...
Bhupendra Singh's user avatar
-1 votes
1 answer
321 views

Seeking CSMapMaker (QGIS Plugin) equivalent for ArcGIS Desktop?

I'm looking for a tool or script or set of operations to mimic the output from a certain QGIS plugin called CSMapMaker, wherein curvature, slope, and a gaussian filtered DEM are overlain one another ...
Michael's user avatar
  • 405
0 votes
1 answer
877 views

R raster::terrain function curvature function missing (version 2.6-7)

I am trying to apply a predictive model based on terrain to a geographic area. I am trying to do this using R and the package raster. The model was developed using GRASS, but I have a limited ...
Smerla's user avatar
  • 390
1 vote
0 answers
416 views

In ArcMap, what are the units of curvature? Degrees/100m?

The help function for ArcGIS' curvature tool just says the units are per 100 z units (which in my case is meters). I am not sure what unit per 100 meters it is though.
Evangeline Eldridge's user avatar
2 votes
1 answer
355 views

Planning a roadbed in QGIS

I am just starting to look into the QGIS project. I wish to plan a roadbed on my property. I would like to start with a map with topographic information (height, direction, distance) and draw the ...
Oystein Skjaeveland's user avatar
4 votes
2 answers
7k views

What are the main drawbacks of the AuthaGraph projection?

The AuthaGraph projection has recently been hyped as the "perfect projection" for a world map, since it (approximately) conserves area, shape and distances. It also tessellates, so that any point can ...
DK2AX's user avatar
  • 183
2 votes
1 answer
688 views

Calculating curvature in SAGA?

I have calculated curvature using ArcGIS (curvature) and SAGA (Slope, Aspect, Curvature; based on 9 parameter 2nd order polynom (Zevenbergen & Thorne 1987) method), however, the output rasters are ...
ami's user avatar
  • 767
3 votes
1 answer
270 views

Information about algorithm used by Terrain models

I have calculated slope and aspect using the DEM (Terrain models) GUI in QGIS Essen. I was also able to calculate the profile and tangential curvature using the toolbox r.slope.aspect. I was wondering ...
Alex's user avatar
  • 53
1 vote
0 answers
39 views

Batch create curved polyline in ArcGIS [duplicate]

How can I batch create curved linear features i.e. using 3 points in ArcPY? The real question is, whether we can create curved linear feature through arcpy or we have to use ArcObjects! Because, to ...
Farid Cheraghi's user avatar
2 votes
0 answers
609 views

Raster terrain curvature analysis in QGIS

When QGIS performs a curvature analysis of the terrain raster, which curvature analysis does this represent i.e. the Gaussian curvature analysis, or Mean curvature analysis? Understanding curvature ...
marco's user avatar
  • 1,147
2 votes
3 answers
2k views

calculating sinuosity of each road segment

I want to calculate the sinuocity of each road segment of a vector shapefile which contains roads. I have downloaded the python script from enter link description here but I don't know what to do ...
Ilias Machairas's user avatar
1 vote
1 answer
2k views

Finding angle between vertices to estimate curvature in the same feature class using python script?

Background info What I'm attempting to create is an estimation of curvature, by finding the angle between vertices. The vertices layer was created from using the "Split line at vertices tool" on a ...
Sam Dotson's user avatar
3 votes
4 answers
5k views

Determining curvature of polylines

I'm dealing with several thousand polylines of Geologic data with mixed degrees of curvature. I'm attempting to quantify just "how curved" these lines are and was curious if there was a means to do ...
morrismc's user avatar
0 votes
1 answer
1k views

Google Earth: Circular polygons that follow earth curvature

I'd like to draw filled circles in Google Earth which follow the curvature of the earth, i.e. for 1000ft altitude, not only the circle's edge but also the center is required to be 1000ft above ...
Cpt Reynolds's user avatar
8 votes
2 answers
383 views

Tool that modifies number of vertices but not the feature itself

Do you know the reason, why some ArcGIS tools (like Clip and Intersect) modifies number of vertices, even if the feature is not modified itself? Like on the picture, I use Clip and Intersect on line ...
david_p's user avatar
  • 1,783
0 votes
1 answer
360 views

Regarding ARCGIS Curvature values [closed]

I originally had a DEM .tif raster in Decimal degrees. I projected it into a PCS with the spatial reference in ArcGIS as: WGS_1984_UTM_ZONE_44N Then, I took the Curvature tool and with a Z-factor of ...
Corse's user avatar
  • 446
4 votes
2 answers
2k views

Using cubiccurve in OpenLayers 2?

I want to use cubiccurve in openlayers 2.13, And I have added the necessary files, But when drawing the line is drawn instead of the curve. Files are available on the website: http://trac.osgeo.org/...
Samane's user avatar
  • 989
3 votes
1 answer
574 views

A point due east of me is closer to the equator? [duplicate]

This footnote: East-west directions can be misleading. Point B, which appears due East from A, will be closer to the equator than A. Thus the curvature found this way is smaller than the curvature ...
Dave's user avatar
  • 266
0 votes
0 answers
591 views

Slope and Curvature values

From an SRTM DEM I have calculated the slope of the terrain with values that range from 0 to 77 (degrees). I have also calculated the curvature of the terrain and the statistical characteristics of ...
Maria Karypidou's user avatar
2 votes
1 answer
4k views

How can I calculate the radius or curvature of a meandering river?

I want to calculate the radius of curvature of a meandering river with ArcGIS 10.1. I have used the Planform Statistic Tool, developed by the National Center for Earth-surface Dynamics, to calculate ...
Krahsin's user avatar
  • 105
6 votes
1 answer
318 views

Curvature computation for different scales

I would like to assess terrain curvature, i.e. the 2nd derivative of a DEM, on different scales. The most common approach to curvature seems to be the one suggested by Zevenberg (1987) where a ...
Leo's user avatar
  • 61
3 votes
0 answers
3k views

Is there simple way to calculate radius of curvature along polyline?

I am digitizing a sinuous linear alignment (in this case a water pipe) and would like to get the radius of curvature of the various bends along the alignment. The main reason is that the minimum ...
Oliver's user avatar
  • 31
1 vote
1 answer
159 views

Profile curvature and soil moisture correlation: issue in interpretation

I have a question related to the profile curvature values. In an article I was reading (reference provided at the bottom of this question), scholars have found a negative correlation between profile ...
NewAtGis's user avatar
  • 1,536
1 vote
0 answers
407 views

interpreting the negative and positive values of profile curvature map in GIS [closed]

I would like to have help in interpreting the values returned by ArcGIS for profile curvature. By reading this Esri's webpage (http://blogs.esri.com/esri/arcgis/2010/10/27/understanding-curvature-...
NewAtGis's user avatar
  • 1,536
7 votes
1 answer
8k views

Radius of curvature for curves in road segments for entire road network

I have a road network shapefile for a US state and I am trying to derive the radius of curvature for road segments in this shapefile. I need to be able to perform this task within just a few functions ...
VT2's user avatar
  • 71
8 votes
1 answer
9k views

Is there a QGIS bezier curve tool?

I'm a recent convert to QGIS but have been confused about the lack of support for drawing curved shapefiles, especially when Arc has almost too many. A lot of the work that our consultancy do is based ...
aheigins's user avatar
  • 213
3 votes
0 answers
571 views

Finding coordinates of tangent points and intersection of curved line? [closed]

I have a line with curves in it. Is there an easy way to extract the X Y values for the tangent points and intersection points in ArcMap 10.2.1? Hopefully my simple paint diagram clarifies what ...
DMusketeer's user avatar
3 votes
1 answer
1k views

Grid-like lines appearing after using Curvature tool

I have been attempting to use the Spatial Analyst Curvature tool with mixed results. I originally tried to use it with a raster that was projected using a 1983 Teale Albers projection and the results ...
Scott's user avatar
  • 31
2 votes
1 answer
614 views

Raster terrain analysis on QGIS 2.0.1 - No curvature analysis?

I need to perform a curvature analysis on a DEM. I've found this tutorial http://www.gistutor.com/quantum-gis/20-intermediate-quantum-gis-tutorials/48-quantum-gis-qgis-raster-based-terrain-analysis-...
joaofm's user avatar
  • 63
0 votes
1 answer
625 views

What Z-factor to set in Curvature (spatial analyst)?

I'm making a slope curvature map, my DTM is 5*5 meters cells, in a meter grid projection. The elevation is in meters asl. When using the Curvature tool for different units of measure, the Z-factor has ...
HDunn's user avatar
  • 8,666
30 votes
6 answers
16k views

Calculating terrain Curvature in QGIS

I have an elevation raster and I would like to get some basic terrain variables, such as slope, ruggedness, aspect or curvature. The problem is that I don't seem to have the possibility to calculate ...
Damien's user avatar
  • 411
12 votes
1 answer
1k views

Understanding curvature filter of QGIS raster terrain analysis?

I have read the source code of several QGis-1.7.4 raster filters computing slope, aspect and curvature. There is a formula in the filter computing the total curvature that puzzles me. The source ...
Tapadi's user avatar
  • 123
3 votes
1 answer
5k views

How to curve lines between points on a map?

I'm trying to curve the lines between points on a RaphaelJS map like Tata Communications - but how did they do it? What sort of mathematics lie behind these curves - unless ofcourse they're all ...
Mark Boulder's user avatar
59 votes
6 answers
41k views

Why is the 'straight line' path across continent so curved?

This is the result of mapping the straight line path from a point in US to Poland using Distance Measurement Tool. Also, planes from Asia to US would travel almost over North Pole. Why is the path ...
Lazer's user avatar
  • 701
2 votes
1 answer
472 views

How do I calculate curvature using GIS co-ordinates [closed]

I have GIS data for which I would like to calculate where curvature is present. Anyone has done this before, please help.
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