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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473 views

Find Average Elevation - ArcGIS Desktop

I am working with 2 shapefiles. One contains the boundaries of a city, the other contains polylines representing the topographic features of the area. Essentially, the polylines make a topographic ...
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1answer
121 views

How to insert “Topo North Arrow” using ArcObject

Does anyone know how to insert "Topo NorthArrow" using ArcObject C# SDK? There is no example or snippet. I am not sure if it is even available through SDK. Thanks in advance.
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1answer
3k views

Plotting elevation maps and shaded relief images from latitude, longitude, and elevation pairs

I have a set of latitude, longitude, and elevation pairs (roughly a grid of such values, though it is not uniform), and I'd like to be able to plot an elevation map and perhaps also a shaded relief ...
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1answer
92 views

Why do different USGS Topo maps show different elevations for the same control point?

So I have been investigating the area around Jerome and Clarkdale Arizona using different USGS Topographic map sources of the same scale, but different time periods, and find that in some cases, the ...
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0answers
99 views

Where do I find official summit elevations found on USGS topo maps?

I'm creating topo maps for my day hikes guides for national parks. I've already done one for Glacier National Park. When I was working on summits, I downloaded the data for Montana from GNIS and when ...
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1answer
598 views

Topographic Index - Why is upslope contributing area divided by downslope contour width and not upslope contour width?

In the Topographic Index calculation, a is the upslope contributing area per unit contour length. Is the "unit contour length" calculated from examining the contour widths of the downslope cells that ...
2
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1answer
670 views

Negative Topographic Index Values

I am getting negative topographic index wetness values in SAGA GIS - anyone else every get this? Not all negative values, but the minimum of the TWI range is negative for some steep watersheds we are ...
2
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1answer
140 views

How to disassociate roughness from slope

How to measure topographic roughness irrespective of slope in ArcGIS? I have used many methods to generate roughness layers, including TRI, VRM (which is supposed to be less correlated with slope), ...
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2answers
195 views

Why are poles missing from GIS topographic data?

Why are poles data missing from most topographic resources ? Data from 60⁰ to 90⁰ lat frequently missing from topographic GIS data. Example with SRTM4.1: Common sense or deduction lead me to think ...
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218 views

How to develop an elevation profile tool with high precision? [closed]

Similar to the Google Earth elevation profile tool, also similar to this: http://www.geocontext.org/publ/2010/04/profiler/en/?send_comment=success#comments I want to be able to use my own set of ...
3
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3answers
92 views

Ontario Topographic and Property Data

Looking for Ontario topographic data and property line data; willing to purchase the latter. Shapefiles or file geodatabase files would be optimal. In terms of topographic data, I am looking for: ...
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2answers
877 views

GDAL Conversion of US Topo GeoPDFs

I've used GDAL_translate with "--config GDAL_PDF_LAYERS" option to convert US Topo GeoPDFs to GeoTIFF and it works great for creating collarless topos based on the new format. However, I can't get it ...
3
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1answer
178 views

data source for worldwide cross-sections of topographic and bathymetric for woodworking art project?

i am a decent r programmer and statistician, i am able to work with data sets pretty well. i am less familiar with GIS tools, but if given a shapefile i can certainly plot political borders and ...
4
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1answer
477 views

How to create a buffer on a linestring with varying or increasing/decreasing width

I want to buffer rivers/streams for a topographic map. I'm using a PostgreSQL/PostGIS database. Usually, I create buffer with ST_Buffer with a constant width. For example, the width of a river buffer ...
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1answer
128 views

Is there a public CanTopo Web Map Tile Service (WMS / WMTS) available?

Does anyone know of a public CanTopo WMS / WMTS available anywhere? I'm assuming CanTopo is more modern / up-to-date than Toporama? Alternatively, what would be your suggestions for the most pain ...
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1answer
157 views

Overlap between Google Earth and Topographic OSM

First, I have Google Earth and Garmin BaseCamp with OSM maps. I would be satisfied if the solution is only available on one of these software. A third software that combine both view can be ...
2
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2answers
171 views

What USGS maps exist in the 7.5' × 15' metric 1:25,000 series?

While browsing through the library, I discovered that USGS has, in fact, produced some metric maps at 1:25,000. One example is Thendara (NY), 43075-F1-TM-025. As far as I can tell, those maps are ...
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0answers
16 views

Are there any NTS index maps showing the most recent update?

For the Canadian National Topographic System, are there any index maps available that do not only show map numbers throughout the country, but also the most recently available update for each map? As ...
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0answers
242 views

What steps does SAGA GIS take when calculating Topographic Wetness, specifically when handling depression filled (by ArcMap) DEM

I am a grad student involved with hydrological modeling. In the model I work on, we are calculating the Topographic Index (TI; without transmissivity - or set to 1) using Quinn's MFD algorithm. We do ...
2
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1answer
5k views

Can Compound Topographic Index (CTI) / Topographic Wetness Index (TWI) produce negative values?

I am calculating Topographic Wetness Index for a study area using SRTM DEM (90 and 30m). I've seen several versions of TWI (CTI). I have been using: TWI = ln(As +1 / tanB) where As = ...
2
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1answer
78 views

Tiling ArcGIS Desktop Historic Maps

I'm using ArcGIS 10.2 Desktop on a Windows platform. I have georeferenced about a dozen USGS topographic raster maps from around 1900. Each georeferenced map is an now an .mxd file. To the best ...
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3answers
976 views

Topography: How to get the x,y,z coordinates of highest or lowest point/pixel of a raster GIS?

Given a .tiff topographic raster image with mountains and deep sea, I am looking for the x,y,z specifics of the highest or lowest point. The x,y,z values being: altitude (z-coordinate) latitude ...
3
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1answer
855 views

Mapping points from total station data in Angle, Horizontal Distance, Vertical Distance

I am working on creating a contour map from total station topo points in ArcGIS 10. The points were collected using H angle, HD, VD instead of XYZ points. I need to create points from these ...
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2answers
2k views

how do you identify ridges on an elevation raster?

I was wondering whether anyone might be able to tell me in layman's terms how to extract or differentiate between ridges and hilltops from 10m elevation data using ArcGIS 10.1? Any advice would be ...
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0answers
157 views

How to compute surface of raster or any point using ARCGIS?

I have a raster image whose values are a digital elevation model of terrain. I need to know the surface type (topographic characterization) of particular points along transects of this DEM. How to ...
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576 views

Why does Topo to raster tool stall in ArcMap 10.1?

I'm having the following problem - An 8 mile by 4 mile set of 2 foot contours. Whenever I start the topo to raster tool, I get a constant loop of the tool running. And running, and running, and ...
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2answers
479 views

Where can I programmatically download SRTM_V4.1 data?

SRTM v4 is an effort by the folks at CIAT-CSI to scrub, polish, and remove gaps in the raw SRTM data released by NASA (SRTM 3). One userfriendly interface : http://dwtkns.com/srtm/ provides ...
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1answer
55 views

Rough edges on tiles in QGIS

I'm loading four .ASC files into QGIS, each containing topographical data about a tile of 10 x 10 km. On the map, this data is displayed as black/white and different shades of gray. My problem is that ...
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1answer
45 views

file type needed to add layer containing contour lines

What file format is usable/recognized by qgis to add contour lines to a map? I'm working with Linux Mint 15, and qgis 1.7.5
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3answers
340 views

What does this style of line on Topographic maps indicate

If I was reading the purpose of this stackexchange site right, I could also ask general map questions. Not necessarily regarding software. Anyways, I was wondering if someone could inform me what ...
2
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1answer
2k views

Polygonize.py outputs into a single file or simple merge?

Given an unique raster topographic file at start, I want to get vector polygons for elevations thresholds 1m, 200m, 500m, 1000m, 2000m into a single shp file. I first slice my raster into 5 (or more) ...
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1answer
403 views

Gdal_polygonize: How to filter pixels above a given value (elevation)?

Given a topographic GIS raster of one country: Given an elevation threshold n = 50 (meters) How to polygonize pixels when z >= n ? gdal_polygonize.py is not clear on this point. It states This ...
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1answer
1k views

How to conditionnally assign a new value to pixels of a raster image?

Given a topographic GIS raster of one country crop.tif: Given a know pixel value such as elevation (z) is +73 : $ gdallocationinfo crop.tif 1 1 -valonly > 73 Given an elevation threshold n = 50 ...
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2answers
545 views

Gdal: How iterate through all pixels of a raster image?

Given a topographic raster image. How to iterate through all pixels of this raster image ? Solution preferably with gdal, in console. Some other libraries/script could be installed. Related: ...
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1answer
707 views

Gdal: How to get a pixel's value from raster image?

Given a topographic raster image. Given a pixel's coordinate in pixel/lines or geocoordinate. How to get it's pixel value ?
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773 views

Topography: How to convert raster into vector layers?

(nb:This project is part of the #Wikipedia #wikimaps project) 1. Question: How to create vector topographic maps from raster image ? How to convert raster topographic image into closed vector ...
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0answers
734 views

How to limit a specific area in order to have a topographic 3D map using MatLab?

I am using MatLab, I want to build a topographic 3D map, I am following this guide, I have been doing the steps listed on the section Draping Geoid Heights over Topography, and I do not have any ...
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0answers
232 views

cut/fill calculation tool to investigate if there is enough material to achieve a 30 degree slope

This is a cut/fill problem. We have pits that have been dug in the ground, usually rectangular. They have a bund wall around them. They are being rehabilitated by pushing the bund back into the pit. ...
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0answers
294 views

How to calculate Gradient from DEM?

I have a digital elevation model for a catchment area and I would like to calculate the gradient by cells. Is that possible and does anybody know the steps?
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3answers
141 views

Is there anywhere I can download the new USGS Topo TIFS?

Is there anywhere I can download USGS Topo TIFS? The new ones? The USGS site just gives me GeoPDF and their web service restricts the scale you can see them at. Edit : I am looking for the the new ...
2
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2answers
490 views

A library/software to create DEM from a topographic map

In one of my projects I need to digitize video clips showing some natural landscape. Specifically I need to know distances between different areas and elevation levels. I have a topographic map of ...
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2answers
135 views

viewshed analysis for observers wearing visors?

I'm starting with a DEM, and looking to identify every point that can be directly "seen" from any point in a particular polygon on an overlaid layer defining an area on that DEM - like any other ...
3
votes
1answer
100 views

What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?

I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to ...
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1answer
706 views

What are Bands, Dimensions, and Histograms in QGIS?

First; I can see a band as synonymous with a channel in an image editing program like GIMP, is this correct? If so then bands play the role of color mixing and masking. Are there any other ...
3
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0answers
36 views

Library for parsing scientific PDS files?

Does a library exist for parsing the PDS files that scientific planetary data gets shipped as? For example, here's a link to to the lunar topographic data from the Lunar Reconnaisance spacecraft ...
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1answer
197 views

I want to create my own topographic map

I need to create topographic maps for scales between 1:100,000 and 1:500,000. This is due to the fact that the official topographic maps in my country are offered in 5k, 10k, 25k, 50k, 100k and 500k. ...
3
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2answers
187 views

Displaying rectified raster (topos) in Google Earth

Looking for tool or an easy way (limited programming skills here) to display geotiffs in Google Earth. Specifically Canadian topos like this This Geogratis site has the same topos in regular tif and ...
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1answer
502 views

ArcGIS Online Topo Maps

ArcView 10.1 does not have this kind of topo map to "Add Data". Where do I find this type of topo map, preferably free. ArcGIS online does not seem to offer this type of topo, unless I am not seeing ...
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3answers
1k views

What are common methods for converting raster digital elevation data to vector contours?

In researching this I have found many references to the opposite, creating elevation data from contours, but nothing regarding contour creation. Preferably, I am looking for open source solutions like ...
4
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1answer
1k views

Terraserver replacment - source for US Topo maps?

Now that Terraserver has been shut down (or at least that's how it appears), is there an alternative WMS server for US topo maps? Probably too much to hope to find one that provides vector layers ...