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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4
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3answers
156 views

Ways to determine winding topographic characteristics of a river

Are there any methods and/or technical guides on how to classify the degree of winding of river bodies? I have the following polygon layer of roughly 100,000 water bodies and would like to write an ...
2
votes
0answers
37 views

How do you merge overlapping .asc files in QGIS with topography and bathymetry?

Firstly, apologies for any incorrect terminology - this is my first time trying to manipulate GIS data. I have two files. The first is higher resolution (SRTM) topography data for a region of islands ...
2
votes
1answer
74 views

Why does the peak of a mountain appear bright on Radar images

Why does the top of a mountain appear bright on a SAR (radar) image. I know that the peak of a mountain is subject to a layover effect, thus appearing closer on the radar image than the bottom part of ...
1
vote
2answers
36 views

Topographical Elevations for Central Africa and Cameroon

I am using QGIS and I have been faced with the problem of topographical maps. From searching online I could only find data for the United States. Google maps offers elevation contours, however I am ...
0
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0answers
37 views

From DEM to Topographic Wetness Index in SAGA GIS

I have DEM in GeoTIFF format and I wish to calculate Topographic Wetness Index in SAGA GIS. TWI tool in SAGA GIS expects that user provides two values - 'slope' and 'catchment area'. Since there's ...
0
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0answers
13 views

lambertian - non lambertian methods

There is enough literature on the topographic correction of satellite images, but in what cases the non Lambertian methods are preferred (over Lampertian)? do we determine the appropriate method only ...
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0answers
42 views

Calculating “sun time” on areas with high mountains? Topography available

I'm wondering how to proceed if you want to calculate how a location on land will get direct sunshine at a given time on a given date (compared being in the shadow of the mountains)? The area is very ...
0
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0answers
41 views

How to make a map showing the slopes of the terrain

I am not too familiar with techniques, and was looking for ways to make a slope map for a given area. It ended with finding this site and posting the question. We are in the process of zoning a new ...
0
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0answers
35 views

Why does the “local maxima” module in SAGA GIS put so many “maxima” points on lakes and plains?

SAGA GIS puts too many maxima points on plains and lakes. Why does it happen? Is there a way to avoid this? It's not really a big problem (the value is correct) except for the size of the SHP files in ...
1
vote
1answer
264 views

Can we create topographical map of private land using GPS elevation data?

Is there a way to create a relatively precise topographical map of a private land using GPS elevation data? As the land is a little bit over 100,000 square meters, the available regional topographical ...
0
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1answer
63 views

How do I take a contour .shp file and create a separate layer for each elevation?

The end result is to have a .dxf file in which each different elevation resides in a different layer. If at all possible I would like to be able to do the organizing in tile mill, or through some ...
1
vote
1answer
50 views

raster topo map with gaps to DEM

I'm trying to create a DEM from this raster map: I managed to clean all the shapes and text. I tried to write a program which finds the curve pieces and connects them. But, I realized that it is ...
2
votes
0answers
29 views

3D topographic progress compensation by the least squares method

I'm looking for an explanation of the least squares method used in the case of a correction of 3D point network. We have reference points with known coordinates XYZ. We calculate intermediate points ...
1
vote
1answer
45 views

How to combine depth and topography .asc file?

I have a .asc file produced from a hydraulic model. The .asc file contains depth data of flood inundation. I want to superpose the depth asc file with my topography .asc file so I can identify where ...
1
vote
0answers
118 views

Finding Color Palettes?

Anybody can help me to find the three color palettes of the following map?
3
votes
1answer
132 views

Correcting for local topography in calculating TRI from DEM in ArcGIS

I'm currently investigating the use of different equipment in calculating TRI from elevation data using ArcGIS. From the methods available ...
0
votes
0answers
8 views

Finding ocean topography data for Burma?

I would like to find the ocean topography around Burma. I would like to have a detailed topography at a local scale such as the ocean depth next to Dawei and Thilawa. Where could i find these ...
1
vote
1answer
83 views

How to display steep slopes with the use of Contours?

I am using Arc Map 10.1. I have downloaded contour data as a shapefile. Is there any way to use the contours to display steep slopes so 15%-25% or 25% and greater.
1
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0answers
90 views

How can I enhance a topo map I am making as a Christmas gift? [closed]

I am using ArcGIS for Desktop 10.2. I am making a topo map for my girlfriend's brother as a Christmas gift. He is one who will appreciate a good map that was "drawn" in 1958. I know you can ...
5
votes
0answers
76 views

FLAG - fuzzy landscape analysis in GIS

I am trying to identify wetlands using different topographic indexes, e.g. TWI/CTI. And I would like to try out a method called FLAG (fuzzy landscape analysis in GIS), but I don't really understand ...
2
votes
0answers
42 views

Creating QGIS multi-layer Topo Map of Lorraine Region of France?

I have a project I'm working on where I need a QGIS multi-layer Topo Map go the Lorraine Region of France between Metz and Nancy as a starting point, but I don't know where to start. What I need is a ...
2
votes
1answer
137 views

What is Google's source for topographic data?

I'm looking for as detailed as possible topographic data for a certain area and have found information displayed by Google Maps to be far more detailed than what is provided by 7.5 minute maps (from ...
1
vote
1answer
116 views

Learning about bathymetry?

Besides reading about bathymetry, I would like to work on some hands-on training that I can learn about bathymetry. Is there any good bathymetry out there that I can get some training with the ...
4
votes
2answers
123 views

Software for amateur topographic surveys

I'm interested in doing rough topographic surveys using my tripod-mounted Brunton transit compass for azimuth readings and laser rangefinder (and maybe an optical level), so obviously going to be much ...
2
votes
1answer
557 views

Detailed topographical map of Istanbul

I need to acquire a very detailed topographic map of Istanbul, Turkey without any markers. Do you know such sources who provides these kind of maps? I tried to Google it, but the results were far ...
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vote
2answers
202 views

Mercator vs. Web Mercator for Large Scale Topographic Maps

I have 8 terabytes of imagery that is in either lon/lat or UTM projection that I will be using for the basis of large scale topographic maps. I have been studying the differences between Mercator and ...
2
votes
1answer
67 views

How can I properly clip a shape file to get the section I want using QGIS?

I've tried the other "how to clip" instructions here, but consistently get an empty shapefile from the clip. QGIS Version: 2.4.0-Chugiak OS: MacOS 10.10 Input File: San Diego (South Map) 1999 Topo ...
3
votes
1answer
47 views

Looking for detailed relief tiles

A few days ago I stumbled over a map which had beautifully rendered, detailed topographic tiles of the whole world. It was similar to google-physical with a strong contrast (shadow/light) and ...
2
votes
0answers
221 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 ...
2
votes
1answer
2k 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 ...
2
votes
1answer
41 views

basic understanding of ArcGIS for Flex not clear on the concept

I am a complete newbie to GIS so please excuse the simple question. I am looking for someone to point me in the right direction to get some answers and/or maybe provide links to where I can find some ...
3
votes
0answers
78 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 ...
1
vote
1answer
74 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 ...
0
votes
1answer
95 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.
3
votes
1answer
446 views

Recommendations for creating contour map from depth points

I am trying to put together a safe routes map for a local lake. I have an old paper map that has a grid of various depths as points. I would like to draw contour lines through these points and create ...
2
votes
1answer
109 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), ...
2
votes
0answers
167 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 ...
2
votes
3answers
82 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: ...
3
votes
1answer
144 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 ...
5
votes
2answers
329 views

Is there a difference between the Planchon & Darboux and Wang and Liu depression filling algorithms? Other than speed?

Can anyone tell me, based on actual analytical experience, if there is a difference between these two depression filling algorithms, other than the speed at which they process and fill depressions ...
2
votes
1answer
454 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 ...
4
votes
1answer
430 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 ...
0
votes
1answer
96 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 ...
0
votes
0answers
224 views

How do I use the new USGS topo WM(T)S in QGIS?

The WMS link for "Scanned Topo Maps from USA Topo" in http://viewer.nationalmap.gov/example/services/serviceList.html no longer works (HTTP 400). ...
2
votes
2answers
137 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 ...
1
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0answers
12 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 ...
1
vote
0answers
201 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
votes
1answer
76 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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vote
3answers
821 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
votes
3answers
327 views

Gdal: how to get the max and min altitudes of my topographic raster?

Given a .tiff topographic raster image. How to get the altitudes of the highest and lowest point/pixel ?