The vertical and horizontal dimension of land surface

learn more… | top users | synonyms

9
votes
5answers
29k views

Creating profile cross-sections in ArcGIS Desktop?

Because the default 'Profile Graph' tool was not sufficient, I wrote a custom VBA script that creates scaled and exaggerated profile cross-sections in ArcGIS but I need more features: Visualize more ...
2
votes
1answer
7k 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 = ...
9
votes
6answers
1k views

seeking “Available Sky” implementations

I'm looking for implementations of an algorithm called "Available Sky". ArcGIS (Spatial Analyst or GRID) is preferred, but solutions in GDAL, SAGA GIS or others are perfectly acceptable. The ...
19
votes
7answers
7k views

Are there open access terrain tiles with a permissive license like OSM?

Are there open access terrain pyramidal map tiles with a permissive usage license like OpenStreetMap's? I'm building aviation-related maps with Polymaps and need a good raster basemap. The Google ...
6
votes
2answers
365 views

Auto Balancing in EarthWork

I am not sure whether this question belongs here. I think it belongs more to Geo-technical, but anyway, I just give it a shot. During earthwork development, earth terrain has to be cut ( if the ...
2
votes
1answer
180 views

How to get mean geographic direction of a polygon in QGIS?

I have a raster height model and would like to calculate the horizontal geographic direction (north, east, etc. - orientation) of each cell, then calculate then the mean value of all these cells in ...
1
vote
1answer
1k views

OpenLayers & Google Maps: TERRAIN not showing as baseMap

I have a problem with OpenLayers and Google maps: on this page: http://46.37.22.75:8085/public/ I'm loading Google maps TERRAIN with Openlayers.js, everything worked well for about 1 year, but now ...
23
votes
8answers
2k views

How to generate a random but believable digital elevation model?

Is there a way to generate a DEM, programatically or otherwise (arcpy or R?), that will feed into ArcGIS for further spatial analysis? Perhaps this needs to be broken down into smaller incremental ...
18
votes
5answers
5k views

Given a terrain, how to draw the stream flow path?

Assuming I have a terrain, as usual the terrain has ridges, creeks and all the characteristics that you can find on a real life map. Water flows from the top of the mountain into lower area, the path ...
8
votes
2answers
2k views

Floodplain generation given river section polylines, flood level elevation points and a DEM of the land surface [closed]

I am looking to generate flood plain polygons to represent 20 and 100 year flood zones, in the most accurate and efficient way possible, given the following datasets: 1) River cross section polylines ...
4
votes
6answers
3k views

shadow simulation from buildings [duplicate]

is it possible to use hillshade function in ArcMap to calculate shadow areas of buildings or simulate shadows of buildings, using DSM of the buildings and the sun angle and azimuth?
3
votes
2answers
2k views

Is it possible to give 2d contours a Z-height from their attribute table in QGIS? (Or ArcGIS?)

I have a contour data file downloaded from UK Ordnance Survey, which gives 2d contours of an area in gml format (also supplied in .shp format) with the heights of each contour attached to the ...
3
votes
4answers
6k views

Can I convert ESRI Grid (DEM) raster to USGS DEM?

There is a tool for DEM to Raster in ArcGIS but I need to convert my ArcGIS DEM rasters (mostly LiDAR) into USGS DEM. The idea is to import this DEM into Sketchup and create a "sandbox" TIN surface ...
5
votes
3answers
519 views

How do I use the Terrain with Labels basemap in the Map constructor

Seems like all the other basemaps can be used in the esri.Map() constructor, but this one doesn't have a corresponding entry in the list of acceptable values. I've tried just "terrain", and it didn't ...
2
votes
0answers
36 views

Line Layer seems to be floating and shifted after adding terrain effect in Cesium

I had made add a line layer using cesium. In which i had added a terrain effect using the standard cesium terrain provider as below var dataSource1 = new Cesium.GeoJsonDataSource(); var roads = ...
1
vote
1answer
59 views

Basic instructions for loading OS Terrain 50 data

Are there any basic instructions for using the OS Terrain data available online? I do not have an issue extracting - it is all sat in a folder ready to go. What I cannot work out how to do is to ...
0
votes
1answer
1k views

3D Analyst Line of Sight: what am I doing wrong?

As a relatively new user to GIS trying out 3D Analyst tools, I'm trying to run a Line of Sight which is not working the way I'd expect. Note I'm running the tool straight from the toolbox, no python ...
0
votes
1answer
355 views

Why do I get these bands on my Height/Dem/Raster

I can't seem to get rid of them, and I've no idea (ok scrap that, I have a vauge idea) whats causing them. First an apology, yes this is quite a large pic apologies, but here goes: How to ...