Jeffery S. Nighbert


Creating Beautiful "Painted Relief" Using ArcInfo

ArcInfo is a great tool for creating beautiful quality maps. Since winning the "Best Cartographic Publication" at the 1995 user conference (see www.Esri.com user conference proceedings 1995) with an "attention getting" color relief map portraying the Interior Columbia Basin Ecosystem Management Project area, there have been hundreds of inquiries concerning techniques used in creating the colored terrain backdrop for this map. This presentation will cover the process of creating "painted relief" using ArcInfo software and the RGB color model in a number of different mapping situations. The discussion will progress through examples of creating painted relief beginning with the very simple and proceeding to the very complex: (1) gray scale and monochromatic shaded relief maps, (2) single theme painted relief, (3) multi-theme painted relief which highlights study areas, corridors, or other special zones, and (4) incorporation of landscape patterns from satellite imagery into painted relief images.


INTRODUCTION

Map makers have been creating beautiful relief maps for over a thousand years. Shaded relief has long been an essential part of the mapping process and to this day it remains one of the most effective ways to communicate the "lay of the land." From the earliest beginnings, when landforms were conveyed by mere pictures, to modern times, in which satellites transmit up-to-the-minute images for presentations on the evening news, the underlying intent of mapping has remained much the same. Map makers seek to record and communicate geographical information in an accurate and meaningful manner. A good map makes it easy for the reader to visualize the geography of an area. The indication of terrain features within a map context makes understanding the geography easier.

In the world of computers and geographic information systems (GIS), creation of tinted or "painted" relief is not as direct a process as it once was. In the past, relief maps were created by cartographers using artistic implements such as pen and pad, water colors, or air brush and ink to directly apply terrain information to the page. Today's map makers must create "painted relief" by manipulating digital data with computer programs which in turn command mechanical devices to paint the computer screen or plotter paper. Fortunately, ArcInfo provides an abundance of software tools which can be used to easily create beautiful renditions of the Earth's surface for this purpose and since there are ample digital elevation data universally available, painted relief could be created for nearly anywhere on Earth. The diagram below shows a simplified processing model for creating painted relief from digital elevation model data (DEM) utilizing the Arc/Grid System. This processing model was used for generating the examples in this paper.

Diagram 1:Process Model for creating Painted Relief.

Diagram 1. Process Model for creating Painted Relief.



CREATING GRAY-SCALE AND MONOCHROMATIC RELIEF MAPS

"Shaded relief" usually applies specifically to gray scale relief maps. The most basic form of "painted relief" is the shaded relief map. In gray scale form or monochromatic color, the shaded relief map serves as the basis for more advanced styles of relief portrayal. They often serve as a more subtle and toned down portrayal of terrain on a map, without overpowering other information on the map. Examples of gray scale and monochromatic shaded relief can be found in most World Atlases and in popular science interest magazines such as the National Geographic Magazine.

The first step in creating any shaded relief map is to render the areas of shadow and light in accordance to a hypothetical position of the sun in relation to the terrain of the map area. The values of darks and lights across the landscape are a function of the sun's lighting as it strikes the undulations and angular faces of the surface of the land. Recording these darks and lights carefully reveals the underlying morphology of the landscape. Whenever the patterns of shadow and light are displayed, the illusion of a "shaded relief" landscape is created.

In ancient cartography, the illusion of terrain was created by artists who actually drew the mountains in picture form where relief was believed to be. In more recent times, cartographers created relief information by interpreting contour lines and shading the relief with an airbrush. This was a very time consuming, tedious and expensive process, yet the results were impressive. In the digital world, sophisticated software and widely available off-the-shelf digital elevation data, such as shown in Figure 1, interact with powerful computers to create relief information automatically. Most major GIS systems have a special function to create shaded relief. These programs generate shaded relief based on values in a digital elevation file.

Figure 1: Grayscale elevation image of Crater Lake, Oregon that was
used to construct shaded relief examples in this paper.

Figure 1. Gray scale elevation image of Crater Lake, Oregon. This figure as drawn using the following Grid command:

Grid: GRIDPAINT elevation_map value linear nowrap gray


The capability to construct shaded relief is available in the ArcInfo Grid subsystem through the HILLSHADE function. Using this function on a digital elevation dataset, a user could specify the generation of illumination patterns for nearly any lighting situation. But for cartographic purposes, a typical terrain presentation may use a northwesterly azimuth value of 315 degrees and an afternoon solar altitude of 65 degrees. The vertical differences of the elevation values may be exaggerated as much as three or four hundred percent to make the terrain seem more dramatic.

What follows is a command line example of the HILLSHADE function:

Grid: hillshade_map = HILLSHADE(craterlake_elev,315,65,all,3.2)

As shown in Figure 2, most digital shaded relief backdrops use a simple gray scale to portray the relief and that has come to be a "defacto" standard coloration. However, Figure 3 shows that monochromatic displays can be created with equally dramatic results. Whether displayed in a gray scale or monochromatic color scheme, landform and relief patterns become strikingly apparent.

Figure 2: Gray scale shaded relief of Crater Lake, Oregon

Figure 2. Gray scale shaded relief image of Crater Lake, Oregon.
This figure was drawn using the following Grid command:

Grid: GRIDPAINT hillshade_map value linear nowrap gray


Figure 3: Monochromatic relief image of Crater Lake, Oregon

Figure 3. Monochromatic shaded relief image of Crater Lake, Oregon.
The figure was created by first setting a display color range using the Grid SHADECOLORRAMP command, then the Grid GRIDSHADES command.
Below is that command sequence:

Grid: SHADECOLORRAMP 0 255 brown bisque
Grid: GRIDSHADES hillshade_map


Development of the shaded relief (hillshade) model is critical to building relief displays because the pattern of shadows defined by this image reveal the shape and form of the landscape. Conceptually, painted relief techniques superimpose color, texture, and pattern upon the morphology of the land according to distribution of the thematic information being portrayed. Furthermore, the digital values contained in the shaded relief image are critical, mathematically speaking, to any additional processing needed to incorporate and manipulate color, value, and pattern in the development of "Painted Relief."

The product of the Arc/Grid HILLSHADE function is a new dataset with values ranging from 0 to 255. These values are indicative of an 8-bit scale computer programmers often use and are somewhat meaningless in a natural or conceptual model. A more native and useful measurement for hillshade would be "percent illumination." The results of HILLSHADE command can be converted to "percent illumination" by dividing values the HILLSHADE dataset by 255. This creates a new dataset where values range from zero to one. Fully illuminated terrain have pixel values of one or 100 percent, half illuminated pixels have a value of .5 or 50 percent illuminated and totally dark areas have a value of zero or zero percent illuminated. Thinking in terms of percent illuminated, is a more natural way of thinking about illumination in relation to color value. This also facilitates combining the relief information with other information to create dramatic and useful painted relief maps.


"PAINTED RELIEF" - ADDING MEANINGFUL COLORS TO THE TERRAIN

As stated, "shaded relief" commonly refers to a hillshade map portrayed in gray tones. Painted relief refers to the "colorizing" of shaded relief maps by adding additional information from a theme in a GIS, such as elevation categories, vegetation categories, or land ownership categories. That is how painted relief adds meaning and beauty to maps. If themes such as elevation categories were simply colored according to "artistic whim," the map would fall outside the bounds of allowable cartographic license and would no longer be an acceptable product, but by choosing meaningful map data and a tasteful coloring scheme, the map can demonstrate that cartography is truely composed of both art and science. The artistic element in cartography is to enhance map readability and user interest, and to communicate ideas to the map reader.

Creating the colorful terrain backdrops for a map is easy, once the basic relationship between color and shadow is understood. Color behavior on the landscape appears is a function of the sun's relationship to the shape of the land. Changes in a color's value exhibit a linear relationship to the distribution of highlights and shadows as they drape across the land's many folds and undulations. This hypothesis agrees with common sense: a color's value diminishes as shadows darken (green is green in full light but becomes darker green in less light and black in no light). This phenomena is the essential kernel in the processing model for creating "painted relief." A relationship model which resembles these principles is expressed by the simple formula:

P = A * I

where
P is the shaded color value
A is the color
I is the landscape illumination value

The Assignment of Color to Theme Categories

The next step in creating painted relief is to select an additional theme for display and use it's categories or reclass it into usable categories, such as with elevation data. To use elevation data in the painted relief process, values must be categorized into a reasonable number of groups so that distinct colors can be assigned. The elevation category map used in this example is based on a look-up table which classifies elevations by 500 foot increments and creates 22 categories of elevation if the full range of elevation values were present in the map area. This assignment was performed in the Arc/Grid system using the RECLASS function and a look-up table. This elevation look-up table has a file name of elev.lut and is shown below:


/* file name: elev.lut
/* elevation range : reclass value
-10000 0000 : 1
0000 0500 : 2
0500 1000 : 3
1000 1500 : 4
1500 2000 : 5
2000 2500 : 6
2500 3000 : 7
3000 3500 : 8
3500 4000 : 9
4000 4500 : 10
4500 5000 : 11
5000 5500 : 12
5500 6000 : 13
6000 6500 : 14
6500 7000 : 15
7000 7500 : 16
7500 8000 : 17
8000 8500 : 18
8500 9000 : 19
9000 9500 : 20
9500 10000 : 21
10000 20000 : 22

The elevation category map for this example was created with the following command line:

Elev_cat_map = reclass(elev_map * 3.28089,elev.lut)

A scale factor of 3.28089 was applied to the elevation map to convert meters to feet. The resulting grid is displayed in Figure 4.


Figure 4: Gray scale category image of Crater Lake, Oregon

Figure 4. Gray scale elevation category image of Crater Lake, Oregon.
This figure was drawn using the following Grid command:
Grid: GRIDPAINT elev_cat_map value identity nowrap gray


The RGB Color Model

Unlike an artist who can buy paint in the desired color, computers create color through numerical representations, and you must specify those numbers to obtain the desired color. Computer programs utilize color "models" to organize this process. Three popular color models in wide use are the RGB (red, green, and blue) model, the HSV (hue, saturation, and value) model, and the CMY(cyan, magenta, and yellow) model. There is no particular advantage of one over the other. The color model one chooses to use is based on experiences with software, hardware, and other intangibles. In the RGB color model, any given color is composed of red, green, and blue values each with a numerical range of 0 to 255. This model provides a palette of more than sixteen million colors to choose from, although the number of simultaneous colors you can display depends on the color capabilities of the device you are using.

Figure 4 shows a gray scale rendition of the classified elevation map. To assign color to the same elevation dataset, another look-up table is used to relate the reclass value to the RGB value for the desired color. These values are stored in a file called color.lut (shown below). The resulting display is shown in Figure 5.


/* file name: color.lut
/* reclass value red green blue
1 8 129 242
2 113 153 89
3 117 170 101
4 149 190 113
5 178 214 117
6 202 226 149
7 222 238 161
8 242 238 161
9 238 222 153
10 242 206 133
11 234 182 129
12 218 157 121
13 194 141 125
14 214 157 145
15 226 174 165
16 222 186 182
17 238 198 210
18 255 206 226
19 250 218 234
20 255 222 230
21 255 230 242
22 255 242 255
23 255 255 255


Colors are assigned to each reclass value at the time the dataset is plotted or used in analysis.

Figure 5: Color category image of Crater Lake, Oregon

Figure 5. Color elevation category image of Crater Lake, Oregon.
This figure was drawn using the following Grid command:

Grid: GRIDPAINT elev_cat_map value identity nowrap color.lut


Creating the Painted Relief Backdrop

The final steps in creating the painted relief backdrop is to run the Color Behavior Formula for creating painted relief using the classified elevation map and the shaded relief map. In the Arc/Grid system there is no way to run the formula using alpha definitions of color such as green or blue, instead the capability to do this is available in the Arc/Grid system through the use of three related commands: color2red, color2green, and color2blue. The color2(X) commands allow new datasets to be created based on red, green and blue values found in the color look-up table. These color2(X) datasets are then multiplied by the hillshade illumination data and the final red, green, and blue datasets are created. The actual painted relief is created by the GRIDCOMPOSITE RGB command in Arc/Plot where the three final red, green, and blue datasets are displayed simultaneously.

The above process from creating the shaded relief, reclassing the elevation map, and running the color2(x) commands has been captured in an AML program shown below:


/* relief.aml
/* by
/* jeffery s. nighbert
/* bureau of land management
/* 1515sw 5th ave
/* portland oregon 97208
/* phone 503-952-6399
/* email: jnighber@or.blm.gov
/*
/* aml creates "painted relief"
/*
/* assumptions:
/* you're in grid and your window and mapextent are set
/*
/* needs two look-up tables

/* elev.lut - classifies elevation every 500 feet
/* color.lut - green to brown to white color ramp 23 categories water is blue
/*
/* to run:
/* &r relief
/*
/* arg definitions
/* elev_map -- an elevation map with Z values in meters
/*
&echo &on
&args elev_map
/* kill off some maps

&if [exists hill -grid] &then; kill hill
&if [exists illum -grid] &then; kill illum
&if [exists slice -grid] &then; kill slice
&if [exists red -grid] &then;kill red
&if [exists green -grid] &then;kill green
&if [exists blue -grid] then;kill blue

/* The creation of illumination values
/* create a hillshade map then divide by 255

hill = hillshade(%elev_map%,345,65,#,3.28089)

illum = float(hill) / 255

/*The assignment of color to elevation values
/* reclassify elevation using elev.lut

slice = reclass(%elev_map% * 3.28089,elev.lut)

/* Creating the painted relief backdrop
/* use color2(X) commands at the same time use other functions
/* int reduces the size of final grids
/* con(isnull(),255 takes care of nulls in the map and assigns them
"white"

red = int(con(isnull(color2red(slice,color.lut,nowrap) *
illum),255,(color2red(slice,color.lut,nowrap)~
* illum)))

green = int(con(isnull(color2green(slice,color.lut,nowrap) *
illum),255,(color2green(slice,color.lut,nowrap)~
* illum)))

blue = int(con(isnull(color2blue(slice,color.lut,nowrap,nowrap) *
illum),255,(color2blue(slice,color.lut,nowrap)~
* illum)))


/* use "gridcomposite rgb red green blue" to display the results

gridcomposite rgb red green blue


The image in Figure 6 below was generated using the RELIEF.AML given above. This figure shows "painted relief" as most people have come to recognize it.

Figure 6: Painted relief image of Crater Lake, Oregon

Figure 6. "Painted relief" image of Crater Lake, Oregon.
This image was drawn using the following Grid command:

Grid: GRIDCOMPOSITE RGB red green blue


HIGHLIGHTING CORRIDORS AND SPECIAL AREAS - ADDING MORE THEMES TO THE PAINTED RELIEF

The painted relief techniques as discussed above, only consider the combination of a single theme with the terrain. However, thematic maps may require many themes and cartographic features to be displayed. Adding additional themes to the landscape creates some new possibilites and complexities for manipulating the painted relief image. The Cartographer now has to decide what happens when two or more themes overlap. Which theme should get priority? Which theme is more important visually? Should the colors be opaque or transparent? All of these questions now must be addressed by answering the most important question: What is the real purpose of the map and how do these themes contribute to satisfying the overall customer requirements?

Once this question has been addressed, manipulating color can be present a whole set of technical problems to solve. I have prepared two hypothetical examples to explore some of the possibilities.

(1) Suppose the hypothetical requirement is for a painted relief map of elevation categories (like those in the single theme example), but the client wants road corridors and a visitor center highlighted in different colors to illustrate different categories of access. Hypothetical road corridors can be created by buffering roads to a 600 meter width to illustrate traffic types. Each type of access can be assigned a simple color, such as magenta for major road access, cyan for paved access, and orange for other access. Once this theme has been developed, several possible display regimes can be tried. Figure 7 shows what this hypothetical_access theme looks like:

Figure 7: Color category image of Crater Lake, Oregon

Figure 7. Hypothetical Road Access Corridors of Crater Lake, Oregon.
This figure was drawn using the following Grid command:

Grid: GRIDPAINT Hypothetical_access_map value identity nowrap access.lut


One display possibility would be to imbed the ACCESS theme corridors into the painted relief using opaque colors. Datasets may be merged a number of ways in the ARC/GRID system. The procedure to use to generate the combination of the Elev_cat_map and the Hypothetical_access_map is the CON function. The CON function command string used to generate the Elev_access_map is shown below:

Elev_access_MAP = con(Hypothetical_access_map lt 4, Hypothetical_access_map, Elev_cat_map)

The command is actually telling the computer to make the final map equal to the Elev_cat_map except where the Hypothetical_access_map is less than four. In that case, make the values equal to those in the Hypothetical_access_map but add 100 to those values to avoid confusion in the color look-up table. A new colormap was created which contained combinations of the values in the color.lut and access.lut. That file is shown below:


/* file name: Elev_access.lut
/* color values from color.lut
/* reclass value red green blue
1 8 129 242
2 113 153 89
3 117 170 101
4 149 190 113
5 178 214 117
6 202 226 149
7 222 238 161
8 242 238 161
9 238 222 153
10 242 206 133
11 234 182 129
12 218 157 121
13 194 141 125
14 214 157 145
15 226 174 165
16 222 186 182
17 238 198 210
18 255 206 226
19 250 218 234
20 255 222 230
21 255 230 242
22 255 242 255
23 255 255 255
/* add colorvalues from the access.lut
101 255 0 255 /* magenta
102 0 255 255 /* cyan
103 255 165 0 /* orange


The results of combining the Elev_cat_map and the Hypothetical_access_map are shown in the figure 8.

Figure 8: Color Elevation and Access category image of Crater Lake, Oregon

Figure 8. Elevation and Hypothetical Road Access Corridors of Crater Lake, Oregon.
This figure was drawn using the following Grid command:

Grid: GRIDPAINT Elev_access_map value identity nowrap Elev_access.lut


This Elev_access_map can now be fed the color2(X) commands discussed in the previous section and the painted relief containing access corridors will be complete.

Figure 9 was generated using the modified code from the relief.aml.

Figure 9: Painted relief image of Crater Lake, Oregon

Figure 9. "Painted relief" of Hypothetical Access Corridors for Crater Lake, Oregon.
This image was drawn using the following Grid commands:

red_access = int(con(isnull(color2red(Elev_access,Elev_access.lut,nowrap) *
illum),255,(color2red(Elev_access,Elev_access.lut,nowrap) * illum)))

green_access = int(con(isnull(color2green(Elev_access,Elev_access.lut,nowrap) *
illum),255,(color2green(Elev_access,Elev_access.lut,nowrap) * illum)))

blue_access = int(con(isnull(color2blue(Elev_access,Elev_access.lut,nowrap) *
illum),255,(color2blue(Elev_access,Elev_access.lut,nowrap) * illum)))

Grid: GRIDCOMPSITE RGB red_access green_access blue_access


(2) The previous example shows how to add additional themes with opaque color. The second hypothetical example shows how to generate and merge a theme using "transparent" color. In this "made-up" example, the customer wants all the themes shown in the previous map, but in addition wants to show an 8000 meter buffer around the Crater Lake Visitor Center in red. If this feature were to be merged using opaque colors, many important features would be obliterated. Figure 10 shows the 8000 meter buffer area of Crater Lake Visitor Center, Oregon.

Figure 10: 8000 meter bufferzone image of Crater Lake, Oregon

Figure 10. "8000 meter buffer zone image of Crater Lake Vistior Center, Oregon.
This image was drawn using the following Grid command:

Grid: GRIDPAINT bufferzone


To merge color "transparently," the following AML was written to build "painted relief" of the previous Hypothetical_access and Elevation_category map when the visitor buffer map is added transparently. The AML program uses a CON function and basically takes the average rgb value of the corridor and elevation categories and the buffer zone where the buffer zone exists and multiplies those values by the illumination values. Where the buffer zone does not exist it multiplies the rgb values of the access corridor values by the illumination values.

/* transparent.aml
&if [exists visbuf_red -grid] &then; kill visbuf_red
&if [exists visbuf_green -grid] &then; kill visbuf_green
&if [exists visbuf_blue -grid] &then; kill visbuf_blue
/* visbuf.lut is a one color look-up file containing "1 255 0 0"
visbuf_red = con(visbuff == 2,~
((color2red(slicerdsbuf,Elev_access.lut) + ~
color2red(visbuff,visbuff.lut)) / 2),~
color2red(slicerdsbuf,Elev_access.lut)) * float(hill) / 255
visbuf_green = con(visbuff == 2,~
((color2green(slicerdsbuf,Elev_access.lut) + ~
color2green(visbuff,visbuff.lut)) / 2),~
color2green(slicerdsbuf,Elev_access.lut)) * float(hill) / 255
visbuf_blue = con(visbuff == 2,~
((color2blue(slicerdsbuf,Elev_access.lut) + ~
color2blue(visbuff,visbuff.lut)) / 2),~
color2blue(slicerdsbuf,Elev_access.lut)) * float(hill) / 255

gridcomposite rgb visbuf_red visbuf_green visbuf_blue

Figure 11: Buffer zone image of Crater Lake, Oregon

Figure 11. "Painted Relief" of Buffer zone, Access Corridors and Elevation Categories of Crater Lake, Oregon.
This image display was drawn using the following Grid command:

Grid: gridcomposite rgb visbuf_red visbuf_green visbuf_blue


Figure 11 was generated by the transparent.aml program and demonstrates how transparent color can be used with opaque colors combined with relief. This capability adds the ability to display overlapping themes in color and greatly increases the use and utility of multi-theme painted relief.


INCORPORATING LANDSCAPE PATTERNS FROM IMAGERY TO TEXTURIZE PAINTED RELIEF

Another method of enhancing painted relief is to include landscape patterns and textures that are otherwise not incorportated in standard painted relief maps. In the painted relief techniques described in the previous sections, the landscape appears smooth because it is created using average elevation values. We know from nature that a smooth landscape is seldom the case. Texture and pattern are constant characteristics of landscapes. Upon viewing satellite imagery such as Spot or Landsat Thematic Mapper (TM), this becomes very apparent. How patterns and textures from such imagery can be incorporated into painted relief will be explained below.

Figure 12: TM Imagery (bands 4,5,3)of Crater Lake, Oregon

Figure 12. TM Imagery (bands 4,5,3)of Crater Lake, Oregon.
This satellite image of the crater lake area shows many surface disturbances such as agriculture, forestry and patchiness due to volcanic activity and snow.


One way to capture these patterns and textures is to calculate the "Normalized Difference Vegetation Index" (NDVI) from TM imagery. NDVI measures vegetative biomass and wetness. The higher (whiter) the NDVI value, the greater the vegetative biomass and moisture. The lower NCVI values (darker regions in the image) represent areas of lower vegetative boimass, and are an indicator of surface disturbances, or breaks in the forest canopy. These are the patterns and textures that are to be incorporated into the painted relief image. The NDVI in Figure 13 was generated in ERDAS Imagine software, then imported to ARC/GRID. To isolate the darker (lower) values, Figure 14 was generated in ARC/GRID using the CON function. Areas of low NDVI are show in white (value of 1) and represent all NDVI areas where the pixel value is less than one standard deviation below the mean. A statistical readout of the value in the NDVI image indicated a mean brightness of 111 and a standard deviation of 28, thus the desired values for the Low_NDVI map are all values less than 83.

Figure 13:  NDVI image of Crater Lake, Oregon

Figure 13. NDVI image of Crater Lake, Oregon generated in Erdas Imagine.


Figure 14: Low NDVI areas of Crater Lake, Oregon

Figure 14. Low NDVI areas of Crater Lake, Oregon. (Shown in White)
Oregon.
This image was made using the CON Arc/Grid Function and then displayed with the Grid commands as follows:

Grid: Low_NDVI = CON(NDVI < 83,1,0)
Grid: GRIDPAINT Low_NDVI


Since the purpose of incorporating texture and pattern from imagery is to enhance the smooth appearance of the landscape in painted relief, modifications to both the elevation values and the brightnesses of the hillshade image will be made based on the distribution of the low NDVI values. This process happens in several steps. (1) Using the Arc/Grid CON function, ten meters are subtracted from the crater lake elevation map whereever the low_NDVI map is equal to one (white). (2) Then the Arc/Grid HILLSHADE function is performed on that dataset. (3) The resulting texturized hillshade map is enhanced by brightening pixel values where they correspond to low NDVI values. The new pixel brightness value is calculated by the following formula:

new_pixval = current_pixval + ((255 - current_pixval) * .9)

This process creates a "dimpled" effect in the grayscale illumination model. The "floor" of each dimple is a lighter shade than the surrounding pixel values. This is displayed in Figure 15.

Figure 15. Enhanced hillshade map of Crater Lake, Oregon

Figure 15. Enhanced hillshade map of Crater Lake, Oregon. Oregon.
Below are the Grid commands used to generate the Enhanced Hillshade map:

/* comment - Subtract 10 meters from the elevation map
fcl_elv10 = crater_elv - (fcl_bright10 * 10)
/* generate enhanced hillshade map in two steps
/* 1 hillshade
Hill_map = hillshade(fcl_elv10,345,65,#,3.2)
/* 2 bright hillshade
enhanced_hill = con(Low_NDVI == 1,~
Hill_map + ((255 - Hill_map) * .90),Hill_map)

/* then convert enhanced_hill to enhanced_illum
enhance_illum = float(enhanced_hill) / 255


(4) The final step to build the texturized painted relief map is to add the color elevation category map to the enhanced hillshade map. This will follow the same basic steps shown in section 2 of this paper. The resulting map is shown in Figure 16.

Figure 16. Texturized Painted Relief Map of Crater Lake, Oregon

Figure 16. Texturized Painted Relief Map of Crater Lake, Oregon.

What follows are the Grid commands used to generate the Texturized painted relief map:

/* Creating the painted relief backdrop
/* use color2(X) commands at the same time use other functions
/* int reduces the size of final Grids
/* con(isnull(),255 takes care of nulls in the map and assigns them
"white"

red_texture = int(con(isnull(color2red(slice,color.lut,nowrap) *
enhanced_illum),255,(color2red(slice,color.lut,nowrap)~
* enhanced_illum)))

green_texture = int(con(isnull(color2green(slice,color.lut,nowrap) *
enhanced_illum),255,(color2green(slice,color.lut,nowrap)~
* enhanced_illum)))

blue_texture = int(con(isnull(color2blue(slice,color.lut,nowrap) *
enhanced_illum),255,(color2blue(slice,color.lut,nowrap)~
* enhanced_illum)))


/* use "Gridcomposite rgb red green blue" to display the results

Gridcomposite rgb red green blue


CONCLUSIONS

The above examples demonstrate only a few of the many processes that can be performed to create interesting and beautiful color relief backdrops for mapping and other GIS presentations. It is important to remember that mapmakers create their work to meet the needs of their customers. These "needs" or requirements define everything about a map: how the map will be created, what features will be shown, even what techniques will be used. Creation of a beautiful painted relief terrain map is no exception. The first and most important step in creation of any map is an assessment of the requirements considering needs on a number of levels. Apart from the primary requirement provided by the user, consideration must be given to the map user audience, integration with other mapping activities, the existing mapmaking environment and standards, and new hardware and software capabilities. It is important to consider what type of painted relief is most appropriate for the situation or even if inclusion of the terrain necessary at all. Unfortunately, beautiful maps do not spring spontaneously from the computer whenever the button is pushed. The creation of a beautiful map is often the result of months of work. Therefore, mapmakers carefully must translate many user needs into a single artistic vision, and formulate the necessary processes to efficiently meet the requirements of that vision. Fortunately, ArcInfo GIS software provides an extensive tool kit that can be used to easily generate everything necessary to create beautiful maps to satify customer needs. The onus is on the mapmaker, as it always has been, to properly use them to the best effect.



Author Information:

Jeffery S. Nighbert
Bureau of Land Management
Oregon State Office 955.2
1515 SW 5th Avenue Portland, Oregon 97201
Phone:(503) 952-6399 Fax: (503) 952-6419
Email: jnighber@or.blm.gov


Bios:

Jeffery S. Nighbert has been a geographer with the Bureau of Land Management for over 15 years and is currently the Senior Technical Specialist for Geographic Information Systems (GIS) at the Oregon State Office, located in Portland, Oregon. He has extensive experience in GIS and holds a M.A. in Geography from University of New Mexico.


Some Examples of Painted Relief Maps


The Interior Columbia Ecosystem Management Project Terrain Map. Winner of the 1995 Esri "Best Cartographic Publication" award.

National Byways of Northeast Oregon.