The study and mapping of land surfaces, including relief (relative positions and elevations) and the position of natural and constructed features.

learn more… | top users | synonyms (1)

4
votes
1answer
244 views

Calculating Topographic Exposure with Raster Calculator

I need you help trying to calculate Topographic Exposure (TOPEX) on a DEM in ArcGIS. I am trying to figure out wind exposure on a DEM with 25m cells. There is a great blog post where someone explains ...
3
votes
1answer
121 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 ...
4
votes
0answers
31 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 ...
3
votes
0answers
128 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 ...
3
votes
0answers
32 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 ...
2
votes
0answers
38 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
0answers
410 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 ...
1
vote
0answers
11 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
127 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 ...
1
vote
0answers
385 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 ...
1
vote
0answers
146 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. ...
0
votes
0answers
159 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?
0
votes
0answers
232 views

How can I calculate raster cell area for upslope contributing area

I am new to spatial analysis, and urgently trying to follow this tutorial to generate a topographic wetness index for my area of interest: ...