Dear Dr. Rodriguez,

I always look for the device and source which are most easily accessible at low cost and which you can use with little or no red tape.

In my publications submitted to intenational journals I make frequently use of Google Maps. In case of non-commercial pure scientific studies you are allowed to use these images. You only have to mention the source of the satellite images.

Should you want to see some examples you can browse my list of publications, paying attention mainly to those studies dealing with sedimentology and geomorphology in Latin America which are closest to your study sites. And upon request I can send you a copy of each of the publications.

Cordiales saludos de Alemania

H.G.Dill

Multispectral imaging and thematic mapping allows researchers to collect reflection data and absorption properties of soils, rock, and vegetation. This data could be utilized by trained photogeologists to interpret surface lithologies, identify clays, oxides, and soil types from satellite imagery.

ASTER (15m) Satellite Images

Dear Dr. Willy

I think if you are looking for geological application there are a lot of free sites that offer detailed Landsat images with high resolution. But, first, you should determine the coordinates and the exact area, then download the images. The main issue is not obtaining the images, the issue is how and who will treat and analyze the images to obtain the details you want. In this regard, if you want any help I'm ready to do it.

Areas without trees suggest sulphides may be present near surface.

CENTRAL PART OF THE OKHOTSK SEA BOTTOM RELIEF (VIEWING FROM SPACE) Terekhov Eugeny and Anatoly Viktorovich Mozherovsk(y)(ii)

At this sute. May be it will be helpfool for Your work.

Sincerely

Dear Dr Willy,

the use of satellite images is pivotal in the preliminary phases of the field works to obtain geo-morphological and geo-tectonic information and topographic bases (if necessary), but you are collaborating with an official project of geological mapping of Cuba, so I hope that the photo interpretation will be followed by a field-based detailed geological mapping. However, there are several GIS-based tools for analyzing satellite images, some of which are open source and appliable to QGIS.

Regards,

Angelo Cipriani

Dear Dr Rodriguez,

Interpretation of IR images (e.g. by LANDSAT 7 ETM) may be very helpful in geological mapping, but multispectral images can be used instead of/in association with topographic maps during the field works.

Harald G. Dill:

Sometimes we have used images from Google Maps, but for very regional scales. In this case, for 1:50 000, I don't think the traditional Landsat images contribute much, although if we use Landsat 8 and mix the panchromatic band we could have some results. Another issue, we are in a tropical region and therefore the visible images are greatly affected by the presence of clouds. Also, in our country, the presence of vegetation is very common and this is another problem for mapping rock types.

Thank you very much for your comments and I would like to continue in contact.

Subhash:

It is true, but in our case, the presence of clouds and abundant vegetation complicate the interpretation related to rock cover. ASTER images may be interesting, but they are not always available to us.

Thank you very much for your comments and I would like to continue in contact.

Wael Fathi Galal:

It is true that there are many places from which to download images, but it is not always possible for our national territory and, in addition, images in the visible spectrum are greatly affected by the presence of clouds and abundant vegetation to identify the lithology of rock formations.

Thank you very much for your comments and I would like to continue in contact.

Michael Issigonis:

It is an interesting consideration that is justified by the affectation of this type of minerals to the capacities of the soils.

Thank you very much for your comments and I would like to continue in contact.

Anatoly Viktorovich Mozherovsk:

I will review the material you recommend, although it did not appear directly on your ResearchGate profile.

Thank you very much for your comments and I would like to continue in contact.

Angelo Cipriani:

Of course, in Cuba there is a 1: 100 000 geological map of the entire national territory and numerous places have been studied on larger scales. For this reason, it is desired to move to a higher coverage stage and that is why we are working on the 1:50 000 geological map. Field work is carried out jointly on each sheet of the future map. Precisely we are using satellite images and the possibilities of GIS [QGIS] for interpretation and preliminary orientation.

Thank you very much for your comments and I would like to continue in contact.

Andrey V. Zhuravlev:

It is true and we are using them, but we have the drawback of scale, the presence of clouds and vegetation cover.

Thank you very much for your comments and I would like to continue in contact.

Colleagues, I very much appreciate the comments and suggestions that you have given me. Is it possible that you could send us examples where you have used satellite images for geological mapping? In this way we could assess which images and procedures would be more suitable for our particular case.

I would be happy to join your team. As a start or example of how to do it I would like to process a small sample of both materials. By both - what geological map you have, any scale might be good for my examplification. And the second - the so called satellite image. As for that, you may reply to my address

Roman, We have good geological coverage in the country and we are only improving the resolution of it. For this, we have numerous geologist-geophysical studies throughout the territory and we are interested in using the possibilities that satellite techniques offer today. All work is done here in the country and with available resources.

That wasn't my question. Please, read again what I wrote and find how I answered to get a solution on working with satellite images for geological maps. It's not so hard to understand that an example is an example and a sample is a sample. No one discussed about the coverage in my comment. It was only you. I gave you an answer. Can you reply strictly to what I wrote and not to something that is related but not even proved to be a part of discussion?

Dear Willy Rodriguez , it would be a pleasure to continue exchanging opinions with you.

Keep in touch,

Angelo

Horatiu Roman, I try to respond to you as you requested and even using your own original text.

R: I will be happy to join your team.

W: Your collaboration would be highly appreciated.

R: As a start or an example of how to do it, I would like to process a small sample of both materials.

W: The possibility of sending you materials for that example, which you mention, does not depend on my will, since the data belongs to a geological company and is not personal.

R: For both - what geological map do you have, any scale could be good for my example.

W: We have a national coverage at 1: 100 000, as I already mentioned, as well as numerous information at other more detailed scales.

R: And the second, the so-called satellite image. As for that, you can reply to my address

W: The images that we can use are those that appear free on the internet, since the others we are not in a position to acquire them, on those occasions that are available to us.

In my previous answer, I was just trying to tell you about our specific situation. Now I guess you are satisfied. However, on the Internet there are geological maps at different scales and if you wish, I could point you to a specific area that you could process, according to your own criteria and then exchange about it, using the images and tools that you want. I can indicate any area based on Google Earth.

We can keep in touch and we can interchange about this topic.

Colleagues, to continue our exchange, I would like to know:

- How you have been used Sentinel images for geological mapping?

- How the especialists are being useing Sentinel images for geological mapping?

These images have better resolution than Landsat's and we have very little experience with them.

Appreciating your collaboration,

.I would like to recommend this work done in Brazil by an instinct of renowned knowledge in this area

http://mtc-m12.sid.inpe.br/col/sid.inpe.br/sergio/2005/06.14.12.47/doc/CAP3B_PRMartini.pdf?metadatarepository=sid.inpe.br/sergio/2005/06.14.12.47.29&mirror=sid.inpe.br/banon/2001/04.06.10.52.39

Andre Luiz, o link dos colegas do INPE é muito interessante. É um resumo claro de como eles têm usado imagens de satélite para diferentes fins e com avaliações muito precisas.

Obrigado por sua colaboração e podemos continuar em contato

Dear Dr. Rodriguez,

You mentioned that the vegetation is hampering the utilization of satellite images in geological mapping in your area. I doesn't necessarily have to be so. During fieldwork, some of my older colleagues used particular plants do distinguish underlying lithology. I know that the spectral satellite imaging is used to distinguish vegetation types, so perhaps you could use this to your advantage.

Now, I am not a geobotanist, nor do I have a knowledge of the relevant literature, however a cursorial search showed that there are some papers which touch upon using satellite plant identification in geology, for example see these links: Chapter Geobotany: Vegetation Mapping for Earth Sciences

I am not sure, if such approach would be useful on scale 1:50 000 and if you have time/resources to study/harness an approach that could turn out to be a dead end, so please don't take it as a something warranted. I just wanted to let you know that there is a possible research venue which could partially mitigate the "vegetation problem".

Juraj

Juraj Littva,

I greatly appreciate your collaboration. Precisely this dependence of vegetation-soil was something that we consulted with some specialists here. We have seen some publications about it, but we have no experience in this area. We asked our soil specialists to propose a variant, but we have not had any answers yet. In reality, the rock-soil-vegetation relationship does not seem to have been discussed much here.

The material you recommended to me is very interesting and I think it could serve as a starting point for further study.

I thank you again and we can keep in touch,

Dear Juraj Littva,

No need to thank it is always a pleasure to help a colleague from science

Dear Willy Rodriguez

I think the next article the same can help you:

Article Geology, geochemistry and tectonic setting of Pan-African se...

Congratulations to Andre Luiz Carneiro Luiz Carneiro da Cunha for good work: I do not know the Portuguese language... I read it with a translator... I would like to read it again if it has an English version!

It is interesting that I did not found a satellite map of Cuba which can be used well... Did not have proper contrast.

My question of how you will do good work if you do not have acceptable satellite maps?

Regards,

Laszlo

Laszlo

Precisely that is our biggest problem, because although there are good quality satellite images for our region, in general, they are not available for download and free use.

In our case, most of the available images have the drawback of cloud cover, as well as the presence of vegetation. For all of the above, we established this forum. We are interested in learning about usage experiences for cartography 1:50 000 and more detailed. Based on the accumulated experiences, then, we will try to find the best solution for us.

Thank you very much for your collaboration and we can continue to contact,

Willy Rodríguez

Willy Rodriguez, it is amazing how much you can get from a satellite image!

You need an imagery and a DEM which can be derived it from the imagery( https://www.satimagingcorp.com/services/dem/). Once your have the map you would probably need to plan and conduct a survey for both training and calibration points, to make the process easier make sure to use the same coordinate type as the imagery. Then depending the type of map you prefer (object-based vs pixel-based) you would use the program to create your outputs and then calibrate and validate your output. You may need to correct your imagery to enhance the accuracy of your map.

I'm more than happy to help if you need any further suggestions.

Hi. I will prefer to use freely available sentinel-2B L2A format which is easily available and do not need much preprocessing as it is already processed by ESA using Sen2Cor. For mapping, you can try different algorithm and see which one gives you best results in your area depending on the type of rocks. I have used sentinel 1 & 2, sentinel-1 for radar interferometry and 2 for mapping. All the best Willy Rodriguez

Dear Willy,

Based on the spatial and spectral characteristics proposed for Sentinel-2 and its similarity to Landsat ETM, SPOT, and to a lesser extent ASTER, there seems to be the great potential for developing products that can be used for the geology community. The capabilities of Sentinel-2 for geological mapping are assessed in various studies by simulating a dataset from a reflectance-at-surface airborne hyperspectral image, using Sentinel-2 band specifications.

Cheers

Ankur

Ruqaiya Yousif, very grateful for your comments and we can keep in touch, Willy Rodríguez

Kamil, we are precisely evaluating the use of Sentinel and if possible, could you tell us about your experiences with this sensor for geological mapping. What differences have you found between S-1 and S-2? Keep in touch, Willy Rodríguez

Ankur, very grateful for your comments. Could you tell me about any of the studies you comment on related to the use of S-2 in geological mapping? We keep in touch, Willy Rodríguez

Hi Willy,

Here I have attached the links for the use of S-2 in geological mapping you may find it useful:

Article Potential of ESA's Sentinel-2 for geological applications

https://www.mdpi.com/2072-4292/8/11/883/htm

Article Targeting rare earth element bearing mine tailings on Bangka...

Thanks

Ankur

Ankur, thank you and i will revise the materials that you show me.

We get in contact,

Willy

In the 1980s, our group used pattern recognition for a group of applications in applied geophysics. Since 2018 we have been venturing into the use of data mining for geological mapping with our Geophysical Engineering students. Although there are some published results we would like to know if anyone has had experiences in this direction and if they have used satellite images for it.

Dr. Zhuravlev

Thank you very much for your help. In our case we have used images of the LANDSAT type, but with great difficulties due to the presence of clouds, and so we are trying to use SENTINEL images that could be more useful. Of course, the combined use of these images with digital elevation models greatly improves the results.

If you have an example of use, we would appreciate it if you did not send them to study it.

Greetings and we continue in contact,

Willy Rodríguez

Hi Mr. Welly

My experience for geological mapping, early stage of remote sensing interpretate. Contour topographic based on scale, such as 1:50.000, you must be processing this datas become to hillshade with azimuth, which is 0, 45, 90, 315, so that you will gate DEM based on scale. For compelete DEM, you will overlay to Landsat imagery 8. You can interpretate geological condition in the research area. Apoligize for any shortcoming and thank you very mucah

Hari:

The joint use of the images with the DEM will always be an interesting variant when working on geological mapping.

Thank you so much for your opinion.

Willy Rodríguez

Dear colleague,

In my experience to have made many geological maps in Colombia that have complex geology like Cuba, I recommended use shaded relief images with an appropriate resolution to the scale of 1:50 000 instead of satellite images. Like Cuba is oriented E-W you should select an adequate Azimut to created it. In Colombia, we use a combination of 45 (50% transparency) with 315. We used the same methodology to the Geological Map of South America at a scale of 1:5M. You can see how we made this map at https://youtu.be/RJiR9XhnNn8

Kind regards,

JGT

Hola Doctor Willy.

Si no tienen insumos propios como curvas de nivel a escala 1:50.000 o mayor, modelos digitales de terreno o elevación a resolución de 25 metros o menor. Les recomiendo utilizar la información abierta de satelites como Aster Dem o Sentinel 1A o 2A. Para fotointerpretación a partir de un MDT o MDE utilizo el software abierto o libre de Quantum GIS, donde hay un complemento o plug-in que genera un mapa de sombras con la configuración recomendada por Gantenbein et al 2012, que se llama Batch Hillshader.

Saludos desde los Andes.

Colleagues:

I appreciate the interventions of Hari Wiki Utama, Jorge Gómez Tapias and David Llano in relation to the combined use of satellite images with the DEM, using the possibilities of shading. This combination, without a doubt, has offered interesting results in multiple cartography works and we are using it.

In the country we have topographic maps up to very detailed scales and, in addition, we have also downloaded high resolution satellite information available free on the internet. The information of images of the Lansat and Sentinel type can also be obtained from the sites where they are offered freely.

In response to your appreciated interventions, I would like to share the following questions that, in our case, hinder the work of geological mapping:

1- Do you have experience in using these techniques when there are no abundant outcrops and if there is a considerable thickness of soil?

2- Do you have experience in using these techniques when in addition to the soil there is vegetation covering the area?

3- Could you recommend examples of the use of these techniques in geological mapping when these elements are present?

Greetings and I look forward to your collaboration,

Willy Rodríguez

This will be the part of your Large Scale Mapping

Cartosat 1 data you can use and analyse with the use of image interpretation software ,Ground truthing will be essential

Vibhash chandra jha

The information provided by Cartosat would be interesting, but could inform me about the availability for its use freely. From what I have observed on the mission site, the data is available for certain projects and since there is no catalog, it is impossible for me to verify their existence in the case of Cuba.

Do you know if there is a site for the free download of existing information?

Regards,

Willy Rodríguez

NRSC, Government of India is having the site. Satellite Data details are iavailable on this site. You can place your order as per your requirement.

Vibhash chandra jha

Based on your recommendation, I reviewed the NRSC site, but for our country there are several limitations, in addition the possibility of having free images is scarce and at the moment the existing prices are not very accessible due to the situation created by COVID-19.

Thanks in any way and I appreciate your feedback,

Willy Rodríguez

You can see BHUVAN satellite data of NRSC

Vibhash Chandra Jha I really appreciate your comments but even on the BHUVAN site it is not possible to enter if the user comes from Cuba. It seems that even in India there are limitations similar to those in the USA for us. Although there are many sites where it is said that it is possible to download satellite images from anywhere in the world, in the case of looking for images for Cuba, in most cases it is unlikely. Regards,

At the end of July, during an exchange with some colleagues, I asked them some questions. On this occasion I would like to extend it to other colleagues who can contribute some results:

1- How to proceed when there are no abundant outcrops and there are a considerable thickness of soil?

2- Is there experience when, in addition to the soil, there is vegetation covering the area?

3- Could you recommend examples of the use of these techniques in geological mapping when these elements are present?

Greetings and I hope for your collaboration,

Willy Rodríguez

Identification of Geomorphic signatures using topographic expression and weathering regolith analysis. It results

Yes Patch Dynamics can be used even area is covered by vegetation. Such characteristics reflect different types of vegetation and Geomorphic signatures.

Spectral signature of high resolution satellite data is very useful in such conditions. You can use FCC

¡Hola!

Ah, yes, the no-outcrop dilemma. You're just wandering around beautiful fields, the birds are flying, the flowers are blooming full of color... But there's no apparent way of telling what lies underneath all that. There is only so much we can do with our human eyes and not-so-human hammers.

The key is remote sensing, just as your question suggests. You take your satellite images, aerial photos, gamma-spectrometric maps, etc and match them with your target location. A "pre-made map" based on the different textures/aspects you can divise on the images helps a lot. Really. It is not just for when you know you won't find many outcrops. This is always great help in any mapping campaign.

So, after a few hours seeing cows, birds, grass, flowers and some farmers ("Buenos días, mi amigo!"), you finally find that outcrop you have been looking for.

First of all, you have to take notes, measures, and maybe a few samples. The big picture matters, but you still have to know as much as you can about the single point you're at. Finally, stop and think.

"So we've got ourselves some..." what do you have in Cuba? Limestone? Basalts (you're an island, after all...)? I'm going with limestone and basalts. I hope you don't mind.

"So we've got ourselves some limestone here, now what?"

You throw your point on the "pre-map" you made. "So, this point falls inside this big salt-and-peppery green-red area on the satellite image, and inside this smaller, smooth and gray area on the photo"

What you could draw from it is that the rock you have found in the outcrop (a limestone in this example) should extend throughout the correspondind areas on the images. Maybe the same kind of limestone occurs in that smaller area around it on the photo and a maybe it changes a bit outside it (but still inside the salt-peppery-green-red area of the satellite image).

And so on.

If you have nothing else to go with, this is a good way of doing your mapping.

Of course, pedological changes are also good indicators of what's underneath, so you should always pay attention to colors, grain size, minerals, etc, because maybe your "pre-map" won't be so spot-on (it won't).

So if you're on the field and find a beautiful basalt outcrop, but are standing on a lot of quartz/sand, you can't just say that the whole area of the pre-map is basalt. Maybe it is just a relic, maybe it came from somewhere else.

Maybe you're walking on clayey, iron-rich grounds, but their texture and composition change a little, so you can be more adventurous and say there are compositional variations in the rock.

But remember, these are assumptions, and you can, yes, use your (or someone else's) knowledge of pedology to make them more trustworthy, but you can't be adamant. Maybe you'll say "everything here is basalt, but this, this and that suggest otherwise, but it requires more detail"

As for vegetation, different soils have different nutrients and support different kinds of biomas, so you can use that as a guide.

There are works, as some of our friends here said, about how different materials reflect/emit radiation and interact with light. I should have more, but I can only mention Borengasser et al (2008) and Moreira (2007, in Portuguese) right now. I also don't know what kind of access you have, living in Cuba.

In the end, it all depends on how much you can:

1. gather from image/photo databases, like SRTM, ALOS PALSAR, LANDSAT, spectrometric maps;

2. gather from previous works;

3. can gather from other sciences (spectral analyses of rocks, soils, vegetation);

4. apply on the field (you have to be confident to make;

5. walk. If your area is large (1:50000 is not exactly detail), maybe some variations won't be significant at your scale.

5. stay! If you have 5 days you can't expect to be as accurate as you'd be if you'd had 5 weeks or 5 months;

6. pay! Maybe you can drill some holes, maybe you can send samples to labs.

I hope I've had some kind of use. If you need anything, just ask.

Que vaya bien

Henrique Joncew,

Geophysics does not create "ready-made maps", at least if it is applied creatively and with the necessary knowledge. When using the possibilities of remote sensors, the known responses of the objects of interest are used, that is, their digital signatures. In addition, geophysicists have always correctly used numerous processing techniques that allow obtaining multiple variants and then selecting the best one according to existing geological knowledge.

Of course, the location of the existing outcrops in the studied area is mandatory, because if we do not have the real answer on each lithological type, the task becomes much more difficult. In this sense, his analysis is basic, since it is evident that geology is not a total chaos and certain rules are followed. Also the idea of ​​relating the type of soil and even the vegetation are essential elements, since the soil depends, in general, on the type of rock that underlies it and the vegetation is selective, that is, everything does not grow anywhere.

Precisely, the idea of ​​the question goes in the direction of seeking and exchanging experiences, since knowledge is the result of "trial and error" on many occasions.

Regarding the type of access, this is the most difficult problem to overcome, since we, unlike Brazil, do not have access to all the information currently available. Even the one that is said to be "free and free". For that reason we are exploring what others, in different places, have achieved and then charting our own route.

In relation to your proposal of stages:

1- We have access to many medium and low resolution images, but little access to high resolution ones.

2- Previous work if: geological, soil, tectonic and other maps up to scales 1: 50000/1: 25000, then, we do not start from zero.

3- There are results from other sciences that collaborate in this task.

4- Field work is planned and executed according to the needs, as there are geologist-geophysical units throughout the national territory.

5- The area includes the entire national territory, but works by topographic sheets and in collaboration with territorial companies.

6- Wells, there are a large number in the national territory: oil, mining, hydrogeological, engineering-geological and agricultural. Of course others are provided when necessary.

Finally, it was very interesting to read your comments, some nice and all, although not shared, if listened carefully.

Thank you very much,

Vibhash Chandra Jha, thank you for your recommendations. We have used some of these variants, but we have yet to work with them.

Thanks repeated,

This is my email: [email protected]

You can send me a mail. We can work together on International collaboration.

There are issues relating to Land degradation and desertification also.

Vibhash Chandra Jha

It would be very interesting to be able to achieve some kind of collaboration. The issue of degradation and desertification are also within our lines of work.

I will contact you to try to find common points where we can collaborate.

Greetings and we continue in contact,

Please send me your email ID

Vibhash Chandra Jha About two weeks ago I sent you my contact via email, but it seems you did not receive it. I attach here my mailbox again: [email protected] I hope we can find some common point for a future exchange. Greetings,

Anybody has some experience in procedures used to:

1- Attenuate / eliminate the presence of vegetation?

2- Attenuate / eliminate the presence of soils?

3- Use of data mining in geological cartography?

I have observed some experiences in Asian research. Could anyone comment on that?

I hope some participate.

It could be better if you used ASTER and Hyperspectral Data for Lithological mapping , both have better spectra and spatial resolution.

I recommend to use of multi-look SAR data for mapping of lineaments.

For more details: Article Performance evaluation of multi-parametric synthetic apertur...