The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).

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76 views

MapServer & Raster picking / Elevation data

I have some GeoTIFFs with elevation data, displayed in OpenLayers or Leaflet via WMS from MapServer. I need to be able to request (from the client) the elevation at some point clicked by the user. ...
2
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0answers
69 views

High-level method for offline future road elevation data

I am new to GIS, so please do not hesitate to call me out in providing limited information. I have a .tiff Terrain (elevation) data file for the east coast of the US and a .osm.pbf OSM file for ...
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0answers
23 views

Export 3D data dxf file problems with elevation value

I have the problem that i can´t export a shp file into DXF and include the eleveation value I make all the procedure explane on "export 3D data dxf file 4" but each time I have the folow error: ...
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0answers
47 views

Getting Z values from source points to transfer to points digitized from them?

I have a set of points that I bring into ArcMap as a shapefile, these contain X/Y coordinate data as well as Z data (Elevation). I am using this to digitized from so when I make a new point file I ...
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1answer
172 views

QGIS elevation and relief shade

I am trying to generate a map with terrain and elevation in QGIS and as a beginner I have followed tutorials on how to generate contours and hill shades succesfully. However, I don't know what are the ...
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49 views

Terrain elevation in QGIS

How can I get started with creating a map with elevation just like this one: Basically I need a map that looks like the one above. Can someone tell me where can I get the data, and how do I process ...
2
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1answer
73 views

Adding elevation data to a network dataset

I am trying to add elevation data to my road network to more accurately calculate walking distance to and from schools. I have figured out how to do the network with out elevation, but for the life of ...
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1answer
291 views

SRTM vs Google Earth Pro elevation data

I am working on elevation data for an area in Sudan. Between Google Earth Pro and SRTM elevation data, which one is more reliable?
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45 views

Convert .adf file to grayscale heightmap

I have downloaded a zipped folder containing multiple .adf files with elevation data from http://viewer.nationalmap.gov/. I want to create a 16 bit grayscale heightmap (tif) from the downloaded files ...
2
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1answer
122 views

How to make slope map from elevation map in Lat/Long?

I have an elevation raster map of the world, in Lat/Long. When I make a slope map, the results of the raster cells will be either 0, or values close to 90. The problem seems to be that the Slope ...
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1answer
74 views

ASCII Raster format cellsize

I have a particular .asc file, with elevation data in it. I am wondering if somebody knows, what is the unit for the "cellsize" variable in the header of the .asc file? Here is how the header looks ...
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1answer
51 views

How to return elevation for point data in QGIS?

I have a dataset for the Western USA and want to get elevations for the point data added to the point attribute table. What is the best way to batch process this so the whole operation is done at one ...
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46 views

GPS point elevation vs Contours layer elevation

I have some survey grade GPS points whose elevation is approx 55 feet lower than my contours layer elevations. I am using 1 ft contours and comparing point elevations with contours in the same ...
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1answer
139 views

Find lakes on an elevation raster

I would like to know if there is a way to identify lakes based on an elevation raster (like SRTM or ASTER)? As far as I can understand, it would mean identifying any cell below the elevation of ...
2
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1answer
62 views

How do I find out the sea levels?

I have following elevation data of a region (the higher the altitude, the brigher the points): How can I find out, which areas are filled by water, and which not? Can I assume that if the ...
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1answer
136 views

QGIS - Level curves - Voronoi Polygons

I am facing a difficulty in QGIS (2.8.2): I have three layers: layer 1: layer with points layer 2: layer of level curves (contour lines) layer 3: layer of Voronoi polygons obtained from the points ...
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2answers
125 views

Suitable raster format for elevation data with sub-meter accuracy?

I've got some elevation data represented in ascii gridded xyz-files which I want to convert to a conventional raster format. What's a bit special is that the elevation values have sub-meter accuracy, ...
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1answer
70 views

GRASS 7 Cost surface and elevation points development

I'm a new to GIS and I need some help. At the moment, I'm trying to develop an optimal path across an area by using GRASS 7 features. It is very similar to the task given here. The problem is that I ...
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3answers
901 views

What is the meaning of “Elevation above the surface of the ellipsoid”?

I'm using implementation of Vincenty's algorithms, and I have their class called "position" that requires lat, lon, and elevation defined by: "Elevation above the surface of the ellipsoid". What is ...
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1answer
546 views

How to find all points with certain elevation difference between them in QGIS

I have a point layer (xyz) and want to find all points that have elevation difference of 200m or more. I would like to then draw a line between each pair with the largest elevation difference. The ...
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1answer
78 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 ...
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2answers
113 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 ...
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0answers
61 views

Which elevation data source has the highest precision for Russian Far East?

If I want to get data on the elevation around the city of Artyrom (region around 132.159633, 43.350116), which elevation data source has the data with the highest precision for that region? I found ...
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1answer
75 views

How can I determine elevation levels for a region in Java?

I need to find out the elevation levels for a certain region (center is located at 132.159633, 43.350116). For this purpose I went to the Elevation finder and downloaded there the relevant part of ...
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1answer
66 views

Determining length of roads that fall under low elevation using ArcGIS Desktop?

I am working on a project on sea level rise impacts of roads. Basically I need to determine length of roads that fall under low elevation (from 1m to 5 m elevation). I have a DEM file and road shape ...
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59 views

Raster map source for desktop, commercial application

We develop desktop, commercial application for Architects (c++). In a future update, we would like to provide our customers with the option to automatically create a 3D terrain with appropriate ...
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1answer
141 views

Ranking Elevation using QGIS?

Can QGIS automatically find the lowest land-point in a country and when you would like to, find the second lowest, third lowest land-point and so on? And on that same coin, a software that could find ...
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1answer
58 views

Calculating ground cover along a path

I'm trying to figure out an efficient way of pulling data about ground cover along a specific path, where I know the starting lat/long and the end lat/long. I've found that the USGS has ground cover ...
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0answers
61 views

calculate Z~F from polygon and raster

I have a polygon shapefile and raster layer. How I can calculate the elevation and area (Z~F) relationship for each polygon by using QGIS or ArcMap?
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1answer
229 views

Generate 3D elevation points grid from 3D contour lines!

I have a shape file with 3D contour lines. I want that based on this information to generate for all this area a 3D grid of points with certain distance from each-other like every 50cm. I use ...
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0answers
63 views

From track+waypoints to elevation profile with waypoints

I have a track and waypoints (1) imported in QGIS. I want to calculate the closest point from every waypoint to the track (2). Then, I want a table with data that allows me to draw an elevation ...
3
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1answer
330 views

Performing viewshed analysis with Dutch AHN files in QGIS?

i downloaded the new (dutch hight data) AHN files, and was trying to perform a viewshed analysis at some point near UTRECHT. The plugin (grass plugin) works ok, i tried it before with a dem map. ...
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1answer
146 views

How can I create polygons for a 3D map from a DEM in grass/qgis

I have a SRTM 30m DEM of my area. I want to create a physical 3D terrain map from it (from felt, 3D printer, you name it). I have two questions about this process: With grass r.contour I created ...
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1answer
130 views

Generating elevation 'database' from NED IMG data

I'm starting to work with the NED 1/3 and 1/9 arc-second data. I've been using gdal in Python and QGIS to do some basic conversions of the raw .IMG data from USGS. My goal is to get elevation data of ...
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1answer
35 views

How to input Shapefile point data into a raster and have the raster adjust to the new data?

I have a shapefile with elevation data at specific points. I also have a raster that has incorrect elevation values, but the transition between pixals is what I need. Is there a way to put the values ...
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1answer
38 views

ArcGIS elevation? [duplicate]

I would like to get the elevation of different point in the digital elevation model means around 4000 points would any one please tell me how can it be possible.
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1answer
165 views

Is it better to take the elevation of a GPS unit or that of a Digital Elevation Model?

When searching of gps routes in wikiloc, for the trailrunning race "Transvulcania" I have several routes to look. I downloaded a lot, but every route has a distance between 71 kilometers and 74 ...
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0answers
91 views

Using Raster Calculator with Elevation Data from Contour Map

I am following this tutorial to attempt to determine flooding in the Gulf region based on estimated rises in sea level. I have taken topographic maps from the USGS and used to contouring tool to turn ...
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2answers
137 views

Seeking web service that returns elevation profile between two points and can process 5000 requests per second

I need a web service that provides elevation profile data between two coordinates with request rates at a minimum of 2000 requests per second but preferably at 5000 per second. The distance between ...
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2answers
213 views

Kriging values greater than the most extreme value of the input layer?

I'll admit I don't understand kriging to the fullest. Yet, I've read that the weights should add up to 1 as in IDW and Natural Neighbors. However, surrounding the biggest elevation points of my ...
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0answers
80 views

How to get the elevation of the complete sea floor?

I am not a cartographer, I am an analyst-programmer, I know nothing about SRTM, DXF, PostGIS, QGIS... I just saw those names in other questions... Is there a quick guide where I can learn about this? ...
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0answers
128 views

Modifying DEM elevation data in QGIS using a polygon

I've tried searching through the existing questions but am struggling to find a succinct answer to what I am trying to achieve. For background, I am running a flood model in TUFLOW to help support a ...
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0answers
38 views

Extract value from Raster data by elevation

I have one raster data (AVHRR NDVI value) and one dtm data (elevation value). Is there anyway to know the NDVI value by 50m interval elevation? For example, I wanna know what is the NDVI value for ...
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0answers
54 views

Trajectory / ballistics

I'm trying to calculate if a canon will be able to shoot over a height in the terrain. lets saytThe canon have to be 15'000-18'000m from the target, and the impact degrees have to be over 30 ...
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0answers
38 views

Where can I obtain data on flood sites, land sewage systems, and property value?

I am a college student trying to obtain this data for a class project. If anyone can help that would be great. Basically, my hypothesis for this project is that land sewage systems that have not been ...
2
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2answers
120 views

find elevation for series of (lat,lon) combinations to make 3d model of earth with relief

I would like to say I am a complete novice to the world of GIS, so if I ask stupid questions or make strange assumptions, please point it out and I will try to clarify myself. I would like to make a ...
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1answer
135 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 ...
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0answers
65 views

cutting contour lines over raster (building) areas

I am looking to cut the contours in ArcMap and /or AutoCAD so they don't pass through buildings or roads. Is there a process or code to do this, so it doesn't have to be done manually? Also, looking ...
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2answers
186 views

Where do I get Elevation Data for Scotland?

So I am new here and I arrived here because I have been searching for quality elevation data for the entire Scotland but I have not succeeded yet. Kindly help if you know where to get the data Raster ...
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191 views

How to get elevation of a coordinate given a dtm file out of a PostGIS?

What would be the best way to get elevation of a coordinate out of a PostGIS database (SQL/plpgsql) given a GeoTIFF dtm file? Importing as PostGIS Raster (which seems more costly) and calling ...