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Calculate Terrain Slope Using Surfer 10's Mapping Software

You can calculate the terrain slope of your grid based map (contour, 3D wireframe, or 3D surface map) from any grid node. The terrain slope is reported in degrees from zero (horizontal) to 90 (vertical), and is based on the direction of the steepest descent. Follow along as we display terrain slope using Demogrid.grd from the Samples folder in Surfer 10.

  1. In Surfer select Map | New | Contour Map and then navigate to the Surfer 10 Samples folder and select Demogrid.grd. Click Open.
  2. In the Object Manager right click on Contours and select Rename object. Type Elevation in as the new name and click OK.
  3. From the toolbar select Grid | Calculus and then select Demogrid.grd. Click Open.
  4. In the Grid Calculus dialog click the "+" icon next to Terrain Modeling and then select Terrain Slope. Name your output grid file and choose its location by clicking on the open file icon next to Output Grid File. Click OK and then OK again.Use Surfer 10 to calculate the terrain slope of any grid based map
  5. Go to Map | Add | Contour Layer and select the newly created grid file. Click Open.
  6. Repeat step 2, naming this new layer Terrain Slope.
  7. In the Object Manager select the Elevation contour layer and position it above the Terrain Slope contour layer.Reposition your elevation contour layer and your terrain slope contour layer
  8. Select your Terrain Slope contour layer in the Object Manager and then go to the General Tab in the Property Manager. In the Fill Contours section check the boxes next to Fill contours and Color scale.
  9. Next click on the Levels tab and in the General section select ChromaDepth for the Fill colors.
  10. In the Major Contours section expand the Line Properties subsection and change the Style to Invisible.
  11. Repeat step 10 for the Minor Contours section.

You have now overlain a terrain slope contour map with a corresponding color scale on top of an elevation contour map. Terrain slope contour layer overlaid on top of an elevation contour layer

 

Comments 8

Guest - Ashok on Friday, 04 September 2015 01:08

Hi Jenni,

Thanks. I want to find out maximum slope of an area at a particular distance with respect to a point.

For example, we have a tower at point "X", consider 250m radius from the tower point "X" . Now i want to find out the maximum slope around the tower point "X" in 250m radius
https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQX90QMPJ8fkB6ctt77GGpoRMgHpzyt-S3KVbeqe6Y-KuQ-68_tcW5RYZs

Hi Jenni, Thanks. I want to find out maximum slope of an area at a particular distance with respect to a point. For example, we have a tower at point "X", consider 250m radius from the tower point "X" . Now i want to find out the maximum slope around the tower point "X" in 250m radius [img]https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQX90QMPJ8fkB6ctt77GGpoRMgHpzyt-S3KVbeqe6Y-KuQ-68_tcW5RYZs[/img]
Jennifer Woodson on Friday, 04 September 2015 10:49

Hi Ashok,

Thank you for the explanation. To find the highest slope in an area, I recommend blanking the grid to the desired radius, and viewing the grid info.


    1. You'll need a BLN file that defines the radius as a polygon. Please see this article for instructions to create a BLN file: http://www.goldensoftware.com/knowledge-base/surfer/1095-how-can-i-create-a-bln-file. If you have Surfer 13, you can easily create the radius polygon with the Geoprocessing | Buffer command.

    2. Click the Grid | Blank command to blank the slope grid file with the BLN file defining the radius.

    3. Click the Grid | Grid Info command, and select the blanked grid file created above.

    4. In the Grid Information report, scroll down to the Univariate Grid Statistics section and view the maximum.


For additional statistics about the slope in this radius, you can convert the GRD file to a DAT file (Grid | Convert), open the DAT file in the worksheet (File | Open), sort on Column C (Data | Sort), remove the rows with blanking values, select the desired data, and click the Data | Statistics command.

I've added your vote to our suggestion list for an easier way to find grid statistics in a defined area.

Thanks,
Jennifer Woodson
jennifer@goldensoftware.com

Hi Ashok, Thank you for the explanation. To find the highest slope in an area, I recommend blanking the grid to the desired radius, and viewing the grid info. [list=1] 1. You'll need a BLN file that defines the radius as a polygon. Please see this article for instructions to create a BLN file: http://www.goldensoftware.com/knowledge-base/surfer/1095-how-can-i-create-a-bln-file. If you have Surfer 13, you can easily create the radius polygon with the [b]Geoprocessing | Buffer[/b] command. 2. Click the [b]Grid | Blank[/b] command to blank the slope grid file with the BLN file defining the radius. 3. Click the [b]Grid | Grid Info[/b] command, and select the blanked grid file created above. 4. In the Grid Information report, scroll down to the [i]Univariate Grid Statistics[/i] section and view the maximum. [/list] For additional statistics about the slope in this radius, you can convert the GRD file to a DAT file ([b]Grid | Convert[/b]), open the DAT file in the worksheet ([b]File | Open[/b]), sort on Column C ([b]Data | Sort[/b]), remove the rows with blanking values, select the desired data, and click the [b]Data | Statistics[/b] command. I've added your vote to our suggestion list for an easier way to find grid statistics in a defined area. Thanks, Jennifer Woodson jennifer@goldensoftware.com
Guest - gyeongil on Thursday, 27 August 2015 04:05

this was what I wanted to find.
I got it now.
but is it possible to make a converstion? i.e. degree of slope instead of 0(horizontal) - 90(vertical)?
I have no idea how I can do.

this was what I wanted to find. I got it now. but is it possible to make a converstion? i.e. degree of slope instead of 0(horizontal) - 90(vertical)? I have no idea how I can do.
Jennifer Woodson on Thursday, 27 August 2015 11:58

Hi Gyeongil,

Thank you for your comment. I'm not sure I understand your question. The slope is reported in degrees when using this process. 0 degrees is horizontal and 90 degrees is vertical. Please see the image below.

https://upload.wikimedia.org/wikipedia/commons/e/eb/Pente-Slope_--Degres-Ratio_V1.jpg

If you have further questions, please send them to surfersupport@goldensoftware.com or jennifer@goldensoftware.com.

Hi Gyeongil, Thank you for your comment. I'm not sure I understand your question. The slope is reported in degrees when using this process. 0 degrees is horizontal and 90 degrees is vertical. Please see the image below. [img]https://upload.wikimedia.org/wikipedia/commons/e/eb/Pente-Slope_--Degres-Ratio_V1.jpg[/img] If you have further questions, please send them to surfersupport@goldensoftware.com or jennifer@goldensoftware.com.
Guest - Ashok on Tuesday, 28 July 2015 04:17

Hi,

How to find out slope of a terrain with respect to a point?

Thanks,
Ashok

Hi, How to find out slope of a terrain with respect to a point? Thanks, Ashok
Jennifer Woodson on Thursday, 27 August 2015 11:35

Hi Ashok,

Thank you for your comment. I'm not sure I understand your question. Please send a detailed inquiry to surfersupport@goldensoftware.com or jennifer@goldensoftware.com.

Thanks,
Jennifer Woodson

Hi Ashok, Thank you for your comment. I'm not sure I understand your question. Please send a detailed inquiry to surfersupport@goldensoftware.com or jennifer@goldensoftware.com. Thanks, Jennifer Woodson
Guest - Michela on Thursday, 09 July 2015 13:47

Very helpful, thanks!

Very helpful, thanks!
Jennifer Woodson on Thursday, 09 July 2015 15:22

Hi Michela,

I'm glad you enjoyed the article! Please let me know if you have any questions or require any assistance with Surfer. Additionally, since this article is written for Surfer 10, you may be interested in checking out our latest version of Surfer: http://www.goldensoftware.com/products/surfer#what-s-new

Thanks,
Jennifer Woodson
jennifer@goldensoftware.com

Hi Michela, I'm glad you enjoyed the article! Please let me know if you have any questions or require any assistance with Surfer. Additionally, since this article is written for Surfer 10, you may be interested in checking out our latest version of Surfer: http://www.goldensoftware.com/products/surfer#what-s-new Thanks, Jennifer Woodson jennifer@goldensoftware.com
Guest
Tuesday, 17 January 2017

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