Question

Asked 11 February 2019

University of Applied and Environmental Sciences

How to make a substraction between two DEM's to obtain heights differences?

Hi everybody. I am trying to use two DEMs derived from Alos PALSAR to identify height differences between them and define possible landslides, using the Fill process and the Raster Calculator in ArcGis 10.3 but the results aren't satisfactory.

What's the height error in a DEM from Alos PASAR with a horizontal resolution of 12,5 m?

Is necesary to do any other process at the DEM's before make the substraction to reduce the inherent height error?

Digital Elevation Models

Landslides

Paramathmuni srinivas Kumar

Jawaharlal Nehru Technological University Anantapur

We have a program to calculate the difference in heights between two Dem files. It not only finds out the quantity but it also idenfies whether there is cutting or filling and also the quantity of cutting and filling. Please let me know if you have the requirement we are happy to help you by giving you the details.

Cite

Wisam Mohammed Abed Alqaraghuli

Ministry of Education in iraq

James Varghese

City of Edmonton

Michael John Patrick

University of Washington

Heidi J Kristenson

University of Alaska Fairbanks

Firoz Ahmad

World Agroforestry Centre

Giuseppe Cosentino

Italian National Research Council

Methodo with QGIS:

Raster Menu => Format Conversion => choose "Ascii Gridded XYZ" and you will get the complete list of pixel coordinates.

The volume subtended to the Dem can also be calculated with the appropriate Grass command, which can be found under Menu => Processing => r.volume

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Gáspár Albert

Eötvös Loránd University

Use QGIS Raster calculator (see this link for description: https://docs.qgis.org/2.8/en/docs/user_manual/working_with_raster/raster_calculator.html).

Or:

Use SAGA GIS (comes with QGIS when installing) for DEM raster processing instead of the QGIS commands.

Either way it is recommended to prepare the two DEMs to be in the same coordinate system, and to have the same extent and resolution (resample).

In SAGA you can do this with the Tools panel ->Grid->Tools and then the ->Calculus submenu commands.

For the vertical error I recommend you to search the Google Scholar for published papers using the "Alos PASAR" keyword!

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Paramathmuni srinivas Kumar

Jawaharlal Nehru Technological University Anantapur

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Shaima Saeed

I need to delete the no data values completely from a crop map and I tried the raster calculator method but it didn't work.

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I have DEM derived from UAV mainly using Photogrammetry and another DEM derived using the Ames Stereo Pipeline: NASA's open source software for deriving and processing terrain data. I would like to compare these DEMs . Please suggest some ideas on which statistical approaches could be used.

How can I extract sand dune crests automatically from a 0.1m resolution DEM? I need polylines for historical comparison.

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Asked 1 March 2016

Nicolas Pucino

I am currently extracting cells with zero accumulation value from a Flow Accumulation raster, and I am manually setting a threshold to a Profile Curvature raster in order to extract very high/low values that approximate a dune crest (highly convex/concave). A logical expression is then used for binding the two outcomes together but still, the results aren't satisfactory.

I need the crests to infer dune lateral rates of movement. I am using ArcMap 10.2 with DEM generated by UAV photogrammetry (0.1m) and LiDAR (1m). I am keen on using any other software.

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CFP: IEEE 2025 6th International Conference on Geology, Mapping and Remote Sensing (ICGMRS 2025)

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2 replies

Asked 25 March 2025

Li Yuan

IEEE 2025 6th International Conference on Geology, Mapping and Remote Sensing (ICGMRS 2025) is hosted by School of Remote Sensing and Information Engineering, Wuhan University and organized by Computer Vision & Remote Sensing (CVRS) Lab, Wuhan University, supported by Suzhou University of Science and Technology. ICGMRS 2025 will be held in Wuhan, Hubei, on April 25-27, 2025.

Conference Website: https://ais.cn/u/EzqA3u

---Call for papers---

The topics of interest for submission include, but are not limited to:

◕ Surveying & Mapping

· Photogrammetry

· Aerial Photogrammetry

· Cartography

· City Brains, Smart Oceans and Digital Earth

· Computer Graphics

......

◕ Remote Sensing

· Optical Remote Sensing

· Microwave Remote Sensing

· Remote Sensing of Atmospheric Environment

· Planetary Remote Sensing and Mapping

· Remote Sensing Information Engineering

......

◕ Application of Remote Sensing Technology

· Remote Sensing Monitoring of Carbon Neutrality and Emissions

· Remote Sensing Monitoring of Key Climate Factors of Global Change

· Remote Sensing, GIS and Navigation and Positioning System (3S) Integration and Application

· Meteorological Application

· Marine Applications

......

◕ Maritime Communications

· 6G Maritime Remote Sensing Information Transmission Technology and Related Applications

· Intelligent Maritime Communications

· 5G for Marine Applications

· Maritime Satellite Communications

· Underwater Acoustic Communications

......

---Publication---

The accepted papers will be published by IEEE (ISBN: 979-8-3315-3731-9), which will be submitted for IEEE Xplore, EI Compendex, Inspec and Scopus.

---Important Dates---

Full Paper Submission Date: March 31, 2025

Registration Deadline: April 20, 2025

Final Paper Submission Date: April 20, 2025

Conference Dates: April 25-27, 2025

--- Paper Submission---

Please send the Full paper(word+pdf) to Submission System:

https://ais.cn/u/EzqA3u

Need help: Searching for data for my thesis on groundwater modelling

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2 replies

Asked 13 November 2024

Indrick Abara a Biabak

Hello everyone,

I am a PhD student in Hydraulic Engineering at the School of Environmental Studies at China University of Geosciences (Wuhan), currently working on groundwater modeling. This research is essential for understanding and predicting aquifer behavior to contribute to sustainable water resource management, a crucial challenge in light of current climatic and human pressures.

To advance my work, I am looking for various types of hydrogeological data. Any information, regardless of location or format, would be incredibly helpful! Here are some examples of the data I particularly need:

Aquifer characteristics: Information on depth, porosity, transmissivity, etc.
Precipitation data: Historical precipitation records at regional or local scales.
Water extraction data: Amounts of water used across different sectors (agriculture, industry, domestic) to assess human pressures.
Fluctuations in water table levels: Temporal variations to better understand resource dynamics.

I am open to any proposals or suggestions that could help me in this endeavor. Any contribution, even partial, would be invaluable for my research. Thank you in advance to those who may offer support or share this post.

Best regards,

ABARA A BIABAK INDRICK

Call for conference 2024?

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