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Generalized land cover techniques? yours and Tom Patterson's?

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#1
johnnyh

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Hi all, :D
I've been starting to think about developing a stylistic generalized land cover for use in a variety of maps. I would use this layer at scales of 1:100,000, 1:24,000 and even below for project area use...
I've read everything related to land cover on here, and reliefshading. I very much like the Tom Patterson's texturized forests, as most of the area I deal with is forested.
I have available recent 1m color aerial photography (.sid) and NLCD92. I could find probably any other data that would be useful in the creating of land cover.

So, my question being :), can anyone offer any tips and techniques as to how to create land cover? This knowledge would be most appreciated. TP's paper "Getting real..." provides an overview, but lacks any specifics. I'm messing around in Photoshop round the clock, but if anyone could point me in the right direction (to achieve this textured land cover) I would really appreciate it!
thanks to all,
JohnnyH

#2
Martin Gamache

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Hi all, :D
I've been starting to think about developing a stylistic generalized land cover for use in a variety of maps. I would use this layer at scales of 1:100,000, 1:24,000 and even below for project area use...
.... I could find probably any other data that would be useful in the creating of land cover.

So, my question being :), can anyone offer any tips and techniques as to how to create land cover? This knowledge would be most appreciated. TP's paper "Getting real..." provides an overview, but lacks any specifics. I'm messing around in Photoshop round the clock, but if anyone could point me in the right direction (to achieve this textured land cover) I would really appreciate it!
thanks to all,
JohnnyH



You should check out the canopy cover dataset being generated by the USGS for the continental US for MRLC and NLCD 2000. It would be a good start for the 1:100,000 scale. I've used this data with some other satelite derived data such as NDVI masks to map forests on maps at 1:100k very nicely and written about how to do this.
see:
http://www.mrlc.gov/ for the data.

As for your question...it is a little vague. There is a huge body of literature avaialble on how to create land cover spanning over 3 decades for the satelitte imaging aspect of that question and much longer for other technologies.

Do you mean how to depict Land Cover in maps? I will assume you do since the above question is something that people dedicate their entire career to and not easily answered. Next question is do you want to depict it in an abstract way or in a photo realistic/stylized way. Second the scale of your map and it's intended audience/purpose as well as your data sources will dictate what you can or should do.

It sounds like you want a generalized depiction for use at a wide range of scales. This may be very difficult to achieve if I read you right. Keep in mind that texture has alot of different meanings and varies with scale. Depicting canopy texture on a 100k map is probably innapropriate, but you may want to depict landscape level texture at that scale, i.e clearing, meadows, avalanche paths. The patterns of texture vary with scale as do the techniques to depict them. So it is unlikely that one depiction will work at all scales.

Tom's work does this quite successfully at a variety of scales but he uses widely different data to achieve that. His methods are well documented on his website and are the audience for each of his maps and what he is trying to achieve. I'm not sure there is too much more to add unless you have specific techniques you did not understand. I'd also recomend checking out Pat Dunlavey's work at PD Carto...he incorporates very subtle bump mapping to show canopy texture at some scales and landscape patterns at smaller scales. Well worth it is studying his work young Jedi.... On that same note there was a nice piece of work for a large scale map somewhere in Utah that Brandon Plewe(sp...sorry) showed in a recent issue of Cartographic Perspectives also using bump mapping in a really nice, subtle way. Well worth trying to find.

Lui (from Slovenia) who use to hang out here has done some very nice stuff with VNS software using three dimensional tree models. Maybe you can contact him directly if that is of interest to you.

#3
Lui

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Well as Martin said I'm playing a lot with natural looking mapping. It is my spare time obsession (one of many :) ). Here I can show you some of my work in that area. It's a natural content of map of Lake Bohinj here in Slovenia. The land cover, part of hillshading was made in VNS. First I have to create so called ecosystem map. It was done in Photoshop where I was manually classifing an orthophoto image. Long an painfull job. I was simply drawing bounds of areas with the same cover and filled them with class color. Simple but efective way.

I will continue later. I'm in a hurry.

Lui

Attached Files

  • Attached File  detail.jpg   511.78KB   354 downloads
  • Attached File  map.jpg   426.02KB   396 downloads


#4
johnnyh

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Many thanks, Martin. Sorry for the vague request, I'll try to clear it up.

Mostly, I am interested in steps taken in Photoshop to derive attractive, photo-realistic, stylistic land cover for various scales. I agree, that 1:100k and 1:24k would most likely be two different projects. For source data I have 1m res color aerial photography, and anything else available [for free] on USGS.

The land cover will be used for a variety of audiences and purposes. For example, now I would like to use it for a wilderness area map.

I'm following TP's instructions as close as I can, and doing some experimenting on my own. I will get there eventually, but thought it would be a good idea to check with you pros first, and maybe learn some shortcuts. For example, what technique do you all use to select areas? Magic wand (contiguous or non?) or simply hand select polygon regions? <see next post..>

You mentioned you've written on land cover creation? Is that online, if so could I get a linky? I live on TP's reliefshading, (I will also study PD's) but any other tutorials or posts (anything!) related to land cover you (or anyone) could point me to would be very appreciated! :)

#5
johnnyh

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Well as Martin said I'm playing a lot with natural looking mapping. It is my spare time obsession (one of many :) ). Here I can show you some of my work in that area. It's a natural content of map of Lake Bohinj here in Slovenia. The land cover, part of hillshading was made in VNS. First I have to create so called ecosystem map. It was done in Photoshop where I was manually classifing an orthophoto image. Long an painfull job. I was simply drawing bounds of areas with the same cover and filled them with class color. Simple but efective way.

I will continue later. I'm in a hurry.

Lui


Wow, Lui! Those are amazing, and about exactly what I am trying to create for my area. Unfortunately, I don't have VNS, which looks like a great program, and would have many applications for Forestry. Just so expensive!

What steps do you take to classify in Photoshop? Do you slice out polygon regions piece by piece, or do you use the magic wand tool? Once they are selected, how do you fill them? I've been using the texturizer, with mixed results so far.

Again, very nice land cover. Are the lighter parcels farmed plots?

Attached is a section of Tom Patterson's Kenai Wilderness map. Note the scale. A lot of ground is portrayed, yet I think the textures add value. Also, notice the very small tree stands (above "Clearwater Slough"). This implies to me that TP uses a non-contiguous magic wand to select his forested areas. Could anyone offer insight into what settings or techniques he might be using? So far my magic wand selections haven't been great.

Attached File  TPlandcovr.jpg   94.77KB   353 downloads

#6
Martin Gamache

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I'm pretty sure this kenai Fjords map is done from landcover raster data derived from Landsat imagery by the national park. With this data you have discrete land cover classes of single colors and all you have to do is select non contiguous pixels and you'll select an entire class at once. Or in index mode you can manipulate the colors without doing selections.

But the satellite image has already been processed and classified into disctinct land cover classes. So you are selecting from something like NLCD rather than the source Landsat images.

Does that make sense?

#7
Lui

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Wow, Lui! Those are amazing, and about exactly what I am trying to create for my area. Unfortunately, I don't have VNS, which looks like a great program, and would have many applications for Forestry. Just so expensive!

Well there are another ways to achive that kind of natural looking maps. One is instancing of trees by quasi-random noise creation in ArcGIS. Jeffery S. Nighbert way. The other way could be tree instancing by Image hoze tool in Corel Painter. This is more artistic way. The third and last way to my knowledge is using Photoshop (probably it is not the most optimized way):
You should have a landcover image of forests in solid black color. Convert image to grayscale.
Create duplicate layer. Select nonforest areas (white) in duplicate layer (Select -> Color range: tolerance 0) and delete them.
Use Filter->Texture->Grain: Grain type: soft, Intensity 100%, Contrast 50-75%
Again select remaining black areas with Color range and small tolerance
Invert select and delete
Change image colorspace to CMYK or RGB
Create new Solid Color layer with desired green
Copy/Paste forest texture layer to the Solid Color layer
Add Layer Style to that layer: Bevel&Emboss-> Style:Inner Bevel, Technique: Chisel soft, Depth: as you wish, Size 1-2px
The image is usually to sharp so apply small amount of Gaussian blur to layer (0.5 - 1)
And that it!
My result of this process is shown in attachment. This can be usefull for maps in smaller scales (from 1:10000 downward)

What steps do you take to classify in Photoshop? Do you slice out polygon regions piece by piece, or do you use the magic wand tool? Once they are selected, how do you fill them? I've been using the texturizer, with mixed results so far.

Piece by piece approach. Bottom layer was grayscale orthophoto, upper layer a classification result layer. First I contour polygon of same class with Pencil tool in color of the class then I filled it with Paint bucket tool. Tablet suggested!

Again, very nice land cover. Are the lighter parcels farmed plots?
Thank you! Yes they are. The most demanding landcover type in natural looking mapping is vineyard. But it can be done with some GIS tools.

Bye

Lui

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#8
johnnyh

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I'm pretty sure this kenai Fjords map is done from landcover raster data derived from Landsat imagery by the national park. With this data you have discrete land cover classes of single colors and all you have to do is select non contiguous pixels and you'll select an entire class at once. Or in index mode you can manipulate the colors without doing selections.

But the satellite image has already been processed and classified into disctinct land cover classes. So you are selecting from something like NLCD rather than the source Landsat images.

Does that make sense?


Thanks, Martin. That makes perfect sense and really supplies me with a starting point. Again, many thanks! :)

Great, Lui. Thank you very much. All your tips will greatly help. I will experiment with what I learned and hopefully come up with something acceptable.

Then I'll post in the gallery and try to get more advice. :)

Thanks again!

#9
ravells

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Dear Lui,

I hope you don't mind but I have copied and pasted your post about making the woodland cover into a thread in our fantasy map making forum together with a picture. The link is here .It was such a great tutorial and gives exactly the effects that we strive for in fantasy mapping.

Obviously if you are unhappy with your tutorial being posted there I will remove it.

All the best

Ravi.

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#10
Lui

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Dear Lui,

I hope you don't mind but I have copied and pasted your post about making the woodland cover into a thread in our fantasy map making forum together with a picture. The link is here .It was such a great tutorial and gives exactly the effects that we strive for in fantasy mapping.

Obviously if you are unhappy with your tutorial being posted there I will remove it.

All the best

Ravi.


No, problem. You have linked to original post here and I think that this is fair use. I also hope that this method will serve you well. If you find some improvments, please don't hasitate to upgrade it and post your findings.
I was also doing fantasy maps some years ago. Well those were the times when I own my time. I think that fantasy mapping was perfect for learning and trying out some new cartography approaches. And it is also fun for someone with god complex :D !
Have fun!
Lui

#11
ravells

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Thank you!

It's nice to see that you started with the humble craft of fantasy mapping! By way of reciprocation, here is a tutorial from our GIMP guru, RobA, about creating heightfields using GIMP and POV ray (easily replicated in photoshop). Not suitable if you have exact DEM heights that you want to replicate but maybe quite good if you want a rough and ready heightfield!

I will have a play around with your method this weekend and come back to you with any findings.

All the best

Ravi

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