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Extracting Points Elevations using ArcMap

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#1
missam

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Hello Community,

I am a new user in this forum and also not very experienced with ArcGIS software.

My question is: I am working on road projects with data in .dgn, dwg, dxf, shp formats.

I digitize the points of road lines in ArcMap, and can get the X,Y elevation by coding and also using the relevant tool in ArcTool Box. The file created is a 2D shape file. I also have a topographic map usually in dgn or dwg format, and can load it as a layer in ArcMap either in dgn format or in shape format.

For calculating the elevation or Z coordinate of the road points, I use the join command and join the 2D shape file to the topo file. And can get the elevation of the points and see them in the attribute table of the new 3D file created using the join command. BUT, in this method, the elevation of the points are selected as the elevation of the closest line, NOT the exact elevation.

I also tried to create a tin file from the contour lines of the topo and then use it as the 3D reference, but I couldn't succeed in this method because I couldn't figure it out how to do it? Do I really need to have the Production Line Tool Set (PLTS) for this method? If yes, which one? Foundation, Defense... there are four types, I think.

The reason that I don't want to use the join command, is because I want to extract the exact elevation of the points with the decimal points.

I am using ArcGIS 9.3 (ArcInfo). I hope I have explained my question well. Can you help me, please?

Thank you,
missam

#2
s hubbard

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Hello Community,

I am a new user in this forum and also not very experienced with ArcGIS software.

My question is: I am working on road projects with data in .dgn, dwg, dxf, shp formats.

I digitize the points of road lines in ArcMap, and can get the X,Y elevation by coding and also using the relevant tool in ArcTool Box. The file created is a 2D shape file. I also have a topographic map usually in dgn or dwg format, and can load it as a layer in ArcMap either in dgn format or in shape format.

For calculating the elevation or Z coordinate of the road points, I use the join command and join the 2D shape file to the topo file. And can get the elevation of the points and see them in the attribute table of the new 3D file created using the join command. BUT, in this method, the elevation of the points are selected as the elevation of the closest line, NOT the exact elevation.

I also tried to create a tin file from the contour lines of the topo and then use it as the 3D reference, but I couldn't succeed in this method because I couldn't figure it out how to do it? Do I really need to have the Production Line Tool Set (PLTS) for this method? If yes, which one? Foundation, Defense... there are four types, I think.

The reason that I don't want to use the join command, is because I want to extract the exact elevation of the points with the decimal points.

I am using ArcGIS 9.3 (ArcInfo). I hope I have explained my question well. Can you help me, please?

Thank you,
missam

are you trying to make a 3-D map, or a 2-D map? you may need to clarify a little bit...it sounds like you may be wanting to derive elevation for the road points you digitized? and then maybe label them?
using a topo will not give you z, or elevation values like what you are looking for.
it sounds like you need a DEM (digital elevation model), or some Lidar, that will have elevation (z) values in the data.
i would immediately try to find and download a DEM that covers your map : USGS; use ArcToolbox to create a hillshade from that, and then create your contours from the hillshade, again with ArcToolbox.
use these new layers in your map (adjust them), and i bet it will look alot more like what you want. you could then clip your digitzed layer with the contour layer, and hopefully produce elevation..
little confused as to your digitzed (points) roads >> they should have received x,y when you made them? are you bringing different coordinate system layers together also?
if your wanting a 3-D map, better start checking out ArcScene. :unsure:
s hubbard
www.hubbardmapworks.com
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#3
missam

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Hello Community,

I am a new user in this forum and also not very experienced with ArcGIS software.

My question is: I am working on road projects with data in .dgn, dwg, dxf, shp formats.

I digitize the points of road lines in ArcMap, and can get the X,Y elevation by coding and also using the relevant tool in ArcTool Box. The file created is a 2D shape file. I also have a topographic map usually in dgn or dwg format, and can load it as a layer in ArcMap either in dgn format or in shape format.

For calculating the elevation or Z coordinate of the road points, I use the join command and join the 2D shape file to the topo file. And can get the elevation of the points and see them in the attribute table of the new 3D file created using the join command. BUT, in this method, the elevation of the points are selected as the elevation of the closest line, NOT the exact elevation.

I also tried to create a tin file from the contour lines of the topo and then use it as the 3D reference, but I couldn't succeed in this method because I couldn't figure it out how to do it? Do I really need to have the Production Line Tool Set (PLTS) for this method? If yes, which one? Foundation, Defense... there are four types, I think.

The reason that I don't want to use the join command, is because I want to extract the exact elevation of the points with the decimal points.

I am using ArcGIS 9.3 (ArcInfo). I hope I have explained my question well. Can you help me, please?

Thank you,
missam

are you trying to make a 3-D map, or a 2-D map? you may need to clarify a little bit...it sounds like you may be wanting to derive elevation for the road points you digitized? and then maybe label them?
using a topo will not give you z, or elevation values like what you are looking for.
it sounds like you need a DEM (digital elevation model), or some Lidar, that will have elevation (z) values in the data.
i would immediately try to find and download a DEM that covers your map : USGS; use ArcToolbox to create a hillshade from that, and then create your contours from the hillshade, again with ArcToolbox.
use these new layers in your map (adjust them), and i bet it will look alot more like what you want. you could then clip your digitzed layer with the contour layer, and hopefully produce elevation..
little confused as to your digitzed (points) roads >> they should have received x,y when you made them? are you bringing different coordinate system layers together also?
if your wanting a 3-D map, better start checking out ArcScene. :unsure:



Thank you for your help. I will follow the method you mentioned (using DEM).

Regarding your question whether I try to make a 3-D map; no, I transfer the x,y, and z coordinates of the points in another software that is used for analysis of the roads. Yes, I want to derive the elevation of the road points that I digitize. I also use the elevations as labels for verifying the calculated elevations vs. relevant elevations in topo map. Regarding the X,Y coordinates, for digitizing of the roadway points I create a point shape file and then digitize the points along the 2-D road lines that are in a dgn, or dwg format or over the aerial image of the area, in another layer. In this case, the x, y coordinates are not shown in the attribute table of the newly created shape file and all the records show zero (0), therefore, I run the (Add X,Y) command, then the x,y coordinates are shown in the attribute table of the road points. Regarding your last question, no I do not bring different coordinate system as another layer, just want to add z coordinate for the digitized points, then I copy them to excel and use the coordinates in a another program.

I don't have any experience using the DEM method, but I would be able to figure it out to some extend, if needed, I will again ask you for help. Thank you!

#4
Sv_BG

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I think that if you are using Arcmap and have an appropriate DEM, you can use this tool from the arctoolbox to extract the Z values of your points -

Extract Values to Points (http://webhelp.esri....alues_to_Points).

The tool will create a new point layer, which will have an additional filed with the elevation values extracted from the DEM.

Good luck,
Svetoslav

#5
johnnyh

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Or you can get Hawths tools, one of the best extensions available.

the intersect points tool, here the description:
http://www.spatialec...tools/isect.php

If can do rasters and vector polygons, including layers of both at one time.

#6
missam

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Thank you all, for your helpful comments.

missam




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