Slope map

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01-30-2014 09:05 AM
JuanIrarrazaval
New Contributor
Hello people
I put this thread in this category because I don't know anything about how its done or where it should be. Cartography seemed cool.

Here is the thing. I have isolines every 25 m wich I exported from a CAD shape (I don't know if its relevant), and now i wish to make a slope map (and an elevation one if its relationed ;)) setting my own "intervals" in %.

Hope you can help me and hope I'm in the correct category

;)
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7 Replies
DanPatterson_Retired
MVP Esteemed Contributor
you need the Spatial analyst extension (read...Not Free)
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JuanIrarrazaval
New Contributor
I have that tool I think... when I click on it it apears to me in the frame... but in grey, I mean, I can't input no layer, I can't click.


NNNNNNNNOOOOOOWWW

I convertED the layer into raster, now it let me use it... i don't know how to proceed from now on.....
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RobertBorchert
Frequent Contributor III
Almost all the slope tools require 3D/Spatial Analyst. 

Here is a poor mans idea.

Generate Line length between your points and embed them with elevation at their point.

then export them to a table which you can bring into Excel and generate a graph based on elevation and length.  it is crude but effective.

Hello people
I put this thread in this category because I don't know anything about how its done or where it should be. Cartography seemed cool.

Here is the thing. I have isolines every 25 m wich I exported from a CAD shape (I don't know if its relevant), and now i wish to make a slope map (and an elevation one if its relationed ;)) setting my own "intervals" in %.

Hope you can help me and hope I'm in the correct category

;)
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JuanIrarrazaval
New Contributor
Almost all the slope tools require 3D/Spatial Analyst. 

Here is a poor mans idea.

Generate Line length between your points and embed them with elevation at their point.

then export them to a table which you can bring into Excel and generate a graph based on elevation and length.  it is crude but effective.


Hey rborchert

i think that will generate an slope GRAPH. I need a map with diferent colors that indicate the slope in %, with intervals, like this:

[ATTACH=CONFIG]31012[/ATTACH]

Thanks anyway!!!!!!
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RobertBorchert
Frequent Contributor III
Without spatial analyst it would be very time consuming to do this.  It is doable but will take a lot of work and mathematics

Slope is essentially 2 points on different contours and you calculate the Angle from one point to the other.

The math is simple use of SOH CAH TOA and you could actually calculate en mass in Excel provided you do the leg work.

Going back to my Map Fundamentals class in college.  You place 2 points.  Draw a line to connect them.  Determine the length of the line (hypotenuse) and determine height based on the differences in which contour each point is on.  You will always know one angle is 90 degrees.  However, you won't end up with the nice color map.  But you can have resulting lines with the slope as an attribute.

Now to get complicated you can manually make TINs and create polygons from them that you can color based on slope.  But that would take a lot of work


Hey rborchert

i think that will generate an slope GRAPH. I need a map with diferent colors that indicate the slope in %, with intervals, like this:

[ATTACH=CONFIG]31012[/ATTACH]

Thanks anyway!!!!!!
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JuanIrarrazaval
New Contributor
Without spatial analyst it would be very time consuming to do this.  It is doable but will take a lot of work and mathematics

Slope is essentially 2 points on different contours and you calculate the Angle from one point to the other.

The math is simple use of SOH CAH TOA and you could actually calculate en mass in Excel provided you do the leg work.

Going back to my Map Fundamentals class in college.  You place 2 points.  Draw a line to connect them.  Determine the length of the line (hypotenuse) and determine height based on the differences in which contour each point is on.  You will always know one angle is 90 degrees.  However, you won't end up with the nice color map.  But you can have resulting lines with the slope as an attribute.

Now to get complicated you can manually make TINs and create polygons from them that you can color based on slope.  But that would take a lot of work




I HAVE SPATIAL ANALYST INSTALLED!!

Anyway...........I'd rather die than doing it the other way!!
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RobertBorchert
Frequent Contributor III
Oh well then.  sorry I read in the beginning you were not sure you had it.

First you need to create a TIN from your contours.  You should assign a projection to them. 

use the Search in an ArcGIS session and look for TIN EDGE that will create the TIN from your polyline contours.

Then search for SURFACE SLOPE and it will create a polygon layer for you from the TIN that displays Slope

IF you could find a pre-existing DEM of your location in question it would be a little easier.

I HAVE SPATIAL ANALYST INSTALLED!!

Anyway...........I'd rather die than doing it the other way!!
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