Shade Type Research Articles

The Potential of Shading Devices for Temperature Reduction in High-Rise Residential Buildings in the Tropics

The present study focuses on the effect of shading devices on the indoor temperature of high-rise residential buildings in the hot–humid climate of Malaysia. Several methods can be employed to improve indoor thermal environment, including using a reflective glazing system, using light colors for external surfaces, and using the appropriate thermal properties of external walls and roofs. However, before using any of these methods, it is important to have an optimum shading device to reduce the solar radiation absorption that leads to an overheated indoor environment and an increase in cooling energy loads. Therefore, the main objective of the current paper is to find the extent of a building's solar heat gain and, consequently, the indoor air temperature that is influenced by the external shading devices. A computerized simulation tool (IES<VE>) is used to carry out the investigation, taking Penang as the empirical background of the hot–humid climate. The results indicate that egg-crate shading has a significant impact on decreasing discomfort hours compared with other shading types.

Beam steering for a long range Acoustic Hail and Warning Device for maritime applications

A new means for steering the beam of a phased line array, electromechanical steering, is described and applied to a long range Acoustic Hail and Warning Device (AHWD) developed for maritime applications. In electromechanical steering, the array elements pivot individually resulting in elements being off-set and rotated in the desired steered beam/sound projection direction. A digital signal processor is used to align the phase fronts of the elements due to the mechanical offsets. Electromechanical steering has several advantages over the purely electronic steering of the array. The electromechanically steered beams are not subject to the individual element aperture function attenuation that reduces the sound pressure level (SPL) that commonly occurs for electronically only steered beams at large steering angles. Also, the primary lobe distortion and (lower frequency) onset of grating lobes that occur when a beam is steered electronically is absent with electromechanical steering. In short, with electromechanical steering, the SPL and directivity from the AHWD is entirely equivalent to that obtained by rotating the AHWD to the desired angle with a conventional pan and tilt mount but requires much less space and provides for more flexible mounting options including improved system stealth. In addition, a novel type of line array phase shading is presented which allows the AHWD to be electronically switched from directional mode (typical beam steering highly focused mode) to non-directional wide field of regard for applications that require simultaneous ensonification of targets over large lateral angles. ©2011 Institute of Noise Control Engineering

Effects of Shade Trees on Illuminance in Classrooms in the United Arab Emirates

This study investigated the potential of shade-trees to improve lighting conditions in the indoor space of a standard classroom in the United Arab Emirates (UAE) using computer simulation with the Radiance program. Shade trees are defined as selected suitable types of trees using certain criteria (i.e. evergreen, proper canopy density, proper height, growth in extreme hot climate conditions, safe roots) based on literature survey and consultation with landscape experts. It focuses on analysis of illuminance levels at desk locations (task) inside a standard classroom oriented to the North, East, South, and West for the selected critical times that are relevant to the locality. An initial group of simulation runs was done at the outset to choose proper tree spacing. The dependent variables are illuminance level and illuminance range resulted from manipulating two independent variables, shade tree type and orientation. The simulation runs includes a base case with no shade trees against other improvement cases with shade trees. The findings show the significance of the shade trees for improved lighting distribution and quality. This is evident in the reduction of illuminance ranges throughout the classroom as it is the case with the Neem shade trees at 2 m providing the lowest range from 125–570 Lux on front of the window and from 130–498 Lux on front of the wall. Yet, some reduction in the overall levels of illuminance is experienced (18–31% reduction for North orientation; 87–96% reduction for other orientations) and an increase in the estimated operating hours of electric lighting. Finally, some passive methods such as high strip windows and roof monitors were recommended to compensate for the illuminance reduction, rather than using electric lighting.

Impacts of Altered Light Spectral Quality on Warm Season Turfgrass Growth under Greenhouse Conditions

Warm‐season turfgrass quality declines under shade due to reduced photosynthesis, increased disease pressure, reduced carbohydrate production, tree root competition, and reduced lateral stem growth. Another factor limiting turfgrass growth and development under tree shade is variable qualities of light filtered by trees. However, effects of various filtered wavelengths on turfgrass performance are lacking and deserve research. Therefore, a greenhouse project investigated the physiological and morphological responses of ‘Diamond’ zoysiagrass [Zoysia matrella (L.) Merr.], ‘Sea Isle 2000’ seashore paspalum (Paspalum vaginatum Swartz.), and ‘Tifway’ and ‘Celebration’ bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] to variable light spectral qualities. Light treatments included a control without any shade cloths and four different color shade cloths filtering wavelengths 560 to 720 nm (blue shade cloth), 360 to 520 nm (yellow shade cloth), 360 to 560 nm (red shade cloth), and 360 to 720 nm (black shade cloth). The percent light reduction for each cloth was about 65% relative to the control. Data collected included visual turfgrass quality (TQ), relative clipping yield, relative chlorophyll concentration, relative shoot width, relative root biomass, relative root length density, relative specific root length, and root and shoot total nonstructural carbohydrates. Diamond was the least affected turfgrass by the color shade cloths, while Celebration and Sea Isle 2000 performed similarly. Tifway was the most sensitive turfgrass with the lowest TQ under color shade cloths. Yellow and red shades were least detrimental, while black shade most negatively inhibited parameters measured, followed by blue shade. This study implies different types of shade significantly impact the TQ of warm‐season turfgrasses.

Effect of Light and Moisture Conditions and Seed Age on Germination of Three Closely Related Myosotis Species

Germination of three closely related species from the Myosotis palustris group (M. nemorosa, M. palustris subsp. laxiflora, M. caespitosa) differing in their habitats and capacity for clonal growth, was compared in two greenhouse experiments. To evaluate both inter- and intraspecific variation, each species was represented by seeds from several populations. Final germination percentage and germination rates T50 were compared both between species and populations within species. In the first experiment, we studied the influence of two external factors, moisture and light. Four moisture levels (dry, wet, periodically flooded and permanently flooded soil) and three types of shading (without shading, shaded with green foil, shaded with solid paper sheet) were combined in a complete factorial design. In all three species, total germination percentage was the same in the three wettest treatments, and decreased in the dry treatment. Germination in the treatments shaded with green foil (simulating vegetation cover, which changed light quality) was significantly slower than in treatments without shading and treatments shaded with a solid paper sheet. There were significant differences among species, but we also found very pronounced differences among populations within a species. M. caespitosa had the uniformly highest germination percentage (reaching in some cases 100%) and also fastest germination. Germination of M. palustris subsp. laxiflora populations was slower and reached lower final proportions, and medium variability among populations. Inter-population variability in the final germination percentage was highest, and the final germination the lowest in M. nemorosa. In addition, M. nemorosa, a species typical for permanent meadow communities was delayed by permanent flooding. In the second experiment, we studied the effects of seed age and storage conditions. Three combinations of seed age and storage were used: younger seeds (half year old) with no-chilling, younger seeds with chilling and old seeds (three years old) with chilling. M. caespitosa had again the highest final germination percentage and fastest germination rates T50. In addition, final germination percentage of this species slightly increased with seed age, whereas it decreased in the other two species. The germination behaviour corresponded well to expectation based on species life histories and habitat preferences. Remarkably stable and high germination percentages and fastest germination rates T50 were ascertained in M. caespitosa, a species of disturbed habitats, with lowest capacity for clonal spread. M. palustris subsp. laxiflora (species with highest clonal capacity) and M. nemorosa (species with medium clonal potential) achieved lower, but still very high final germination percentage. In addition, M. nemorosa showed the highest inter-populations variability in our experiments.

USING SIMULATION TO EVALUATE AND IMPROVE THE THERMAL PERFORMANCE OF COURTYARD OFFICE BUILDINGS IN CAIRO

This paper explores the implications of alternative design options for the thermal performance of office buildings in Cairo, Egypt. Typical courtyard office floor plan was selected for the investigation. Multiple design alternatives were considered involving various glazing and shading types, shading schedules, thermal insulation options, orientations, and ventilation scenarios. A numeric thermal simulation application was used to model the performance of these alternatives parametrically*1. The results show the significant degree to which design measures could reduce cooling requirements of (and overheating tendencies in) courtyard office buildings in Cairo.

A new species of Exbucklandia (Hamamelidaceae) from the Pliocene of China and its paleoclimatic significance

Eight fossil leaves identified as Exbucklandia tengchongensis sp. nov. (Hamamelidaceae) were collected from the Pliocene Mangbang Formation in Tengchong, Yunnan Province, Southwest China. The fossil leaves are characterized by the overall rounded lamina with entire margin, actinodromous venation, and cyclocytic stomata, which suggest the affinity within the genus Exbucklandia, particularly with E. populnea. A survey on the cuticles of the sun and shade leaves of modern E. populnea indicates that the shade leaves generally possess more pronounced undulate anticlinal cell walls and a much lower stomatal density than the sun leaves. Two morphotypes, i.e. sun vs. shade types, of the fossil leaves were therefore recognized. The distribution of the modern Exbucklandia suggests that the genus lives under a warm climate with a mean annual temperature (MAT) from 13 °C to 27 °C and a mean annual precipitation (MAP) from 800 mm to 2500 mm. Hence, E. tengchongensis might also live under a similar climatic condition in the Pliocene. Leaf margin analysis on the Tengchong flora supports this result. The little change of Neogene MAT in Southwest China is therefore supported.

Dairy cows prefer shade that offers greater protection against solar radiation in summer: Shade use, behaviour, and body temperature

There is considerable evidence that shade is a valuable resource for cattle in summer, but less is known about the important design features of effective shade. The aim of this experiment was to investigate if lactating dairy cows have a preference for shade that offers greater protection against solar radiation. Shade was provided by wooden structures covered with shade cloth that blocked 25, 50 or 99% of solar radiation. Nine groups of Holstein–Friesian cows (27 animals in total, 3 animals/group) were exposed to three treatment combinations: pair-wise simultaneous presentation of shade cloth that blocked: (1) 50 and 99%, (2) 25 and 50%, and (3) 25 and 99% of solar radiation. Cows were exposed to each combination in a cross-over design (2 d/combination). Shade use and time budgets were recorded during the hottest part of the day (10:00–17:00 h). Within each group, cows were categorised as predominantly black, white, or black and white in colour (one of each coat colour/group) in order to investigate the interaction between coat colour and treatment choice. Cows preferred shade cloth that blocked greater amounts of solar radiation in two of the combinations (99% versus 25%: 72.3% time spent in the 99% option, P < 0.001, S.E.: 3.9%; 50% versus 25%: 72.0% time spent in the 50% option, P < 0.001, S.E.: 3.5%), but showed no preference for shade cloth that blocked 50 or 99% of solar radiation when these two options were presented simultaneously (49.8% time spent in the 99% option, P = 0.509, S.E.: 5.3%). Neither coat colour nor weather conditions influenced preference for shade type. Cows spent more time in shade on days with higher solar radiation levels ( P < 0.001, slope: 0.04%, S.E.: 0.01%) and higher ambient air temperature ( P = 0.021, slope: 2.63%, S.E.: 0.02%). Mean body temperature increased with increasing temperature–humidity index ( P = 0.014, slope: 1.9%, S.E.: 0.7%), heat load index ( P = 0.009, slope: 0.6%, S.E.: 0.2%) and ambient air temperature ( P = 0.065, slope: 2.1%, S.E.: 1.1%). In conclusion, cows preferred shade that provided more protection from solar radiation (50 and 99% blockage versus 25%) and showed behavioural and physiological changes associated with increased heat load.

The impact of venetian blind geometry and tilt angle on view, direct light transmission and interior illuminance

Venetian blinds are a common type of shading. They can reflect and transmit light efficiently into buildings by adjusting the louver angle and at the same time allow some view to the outdoors. This paper presents a systematic method for calculating projected view (or shaded) fractions for venetian blinds of any shape (flat and curved) as a function of rotation angle, taking into account edge effects and slat thickness. General analytical direct transmittance equations and charts – derived from pure geometrical characteristics – were also developed for flat slats (including thickness and edge effects) and curved slats (circle arcs) as a function of blind tilt angle and profile angle. The last part of the paper investigates the impact of slat shape and reflectance on window-blind system effective reflectance and the associated contribution to the inter-reflected component for different window areas.

Intensity of bitterness of processed yerba mate leaves originated in two contrasted light environments

The bitterness intensity of beverage prepared from the leaves produced on the males and females of yerba mate (Ilex paraguariensis), grown in the forest understory and monoculture, was evaluated. The leaves were grouped by their position (in the crown and on the branch tips) and by the leaf age. The leaf gas exchange, leaf temperature and photosynthetic photon flux density were observed. Inter and intra-specific competition for light and self-shading showed the same effect on yerba mate beverage taste. All the shading types resulted in bitterer taste of the processed yerba mate leaves compared to the leaves originated under the direct sun exposure. The leaves from the plants grown in the monoculture showed less bitterness than those grown in the forest understory. This conclusion was completely opposite to the conventionally accepted paradigm of the yerba mate industries. The leaves from the tips (younger leaves) of the plants grown in the monoculture resulted a beverage of softer taste; the males produced less bitter leaves in any light environment (forest understory or in the crown in monoculture). The taste was related to the photosynthetic and transpiration rate, and leaf temperature. Stronger bitterness of the leaves provided from the shade conditions was related to the decreased leaf temperature and transpiration in the diurnal scale.

A Review of Optical Properties of Shading Devices

The optical properties of shading devices have an impact upon the daylighting and thermal performance of a building's perimeter spaces. This chapter presents an overview of past and current approaches in computing the optical properties of shading devices. Optical properties are determined by the different components of visible and solar transmittance, reflectance and absorptance. Emphasis is given to the three major types of shading used today: venetian blinds, roller shades/screens and draperies. Comparisons between experimental procedures and analytical and numerical modelling techniques are presented, and limitations in existing models and standards are discussed. The final section describes the latest generalized methods and models for characterizing complex fenestration/shading systems.

Topography and Crop Management Are Key Factors for the Development of American Leaf Spot Epidemics on Coffee in Costa Rica

ABSTRACT We monitored the development of American leaf spot of coffee, a disease caused by the gemmiferous fungus Mycena citricolor, in 57 plots in Costa Rica for 1 or 2 years in order to gain a clearer understanding of conditions conducive to the disease and improve its control. During the investigation, characteristics of the coffee trees, crop management, and the environment were recorded. For the analyses, we used partial least-squares regression via the spline functions (PLSS), which is a nonlinear extension to partial least-squares regression (PLS). The fungus developed well in areas located between approximately 1,100 and 1,550 m above sea level. Slopes were conducive to its development, but eastern-facing slopes were less affected than the others, probably because they were more exposed to sunlight, especially in the rainy season. The distance between planting rows, the shade percentage, coffee tree height, the type of shade, and the pruning system explained disease intensity due to their effects on coffee tree shading and, possibly, on the humidity conditions in the plot. Forest trees and fruit trees intercropped with coffee provided particularly propitious conditions. Apparently, fertilization was unfavorable for the disease, probably due to dilution phenomena associated with faster coffee tree growth. Finally, series of wet spells interspersed with dry spells, which were frequent in the middle of the rainy season, were critical for the disease, probably because they affected the production and release of gemmae and their viability. These results could be used to draw up a map of epidemic risks taking topographical factors into account. To reduce those risks and improve chemical control, our results suggested that farmers should space planting rows further apart, maintain light shading in the plantation, and prune their coffee trees.

In vitro model to evaluate reliability and accuracy of a dental shade-matching instrument

There are several electronic shade-matching instruments available for clinical use; unfortunately, there are limited acceptable in vitro models to evaluate their reliability and accuracy. The purpose of this in vitro study was to evaluate the reliability and accuracy of a dental clinical shade-matching instrument. Using the shade-matching instrument (ShadeScan), color measurements were made of 3 commercial shade guides (VITA Classical, VITA 3D-Master, and Chromascop). Shade tabs were selected and placed in the middle of a gingival matrix (Shofu Gummy), with tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Reliability, accuracy, and 95% confidence intervals were calculated for each shade tab. Differences were determined by 1-way ANOVA followed by the Bonferroni multiple comparison procedure. Reliability of ShadeScan was as follows: VITA Classical = 95.0%, VITA 3D-Master = 91.2%, and Chromascop = 76.5%. Accuracy of ShadeScan was as follows: VITA Classical = 65.0%, VITA 3D-Master = 54.2%, Chromascop = 84.5%. This in vitro study showed a varying degree of reliability and accuracy for ShadeScan, depending on the type of shade guide system used.

Effects of shade nettings, sowing time and storage on baby spinach flavonoids

AbstractFlavonoids are important in plant interactions with the environment and may have positive effects on human health. Effects of light quality and quantity on flavonoid concentration were studied in baby spinach (Spinacia oleracea L.) cultivated under three types of shade netting differing in transmittance of UV‐B and PAR, at two times during the season. Leaves harvested at two growth stages for each sowing were subjected to different post‐harvest storage conditions. Shade nettings had a relatively small effect on flavonoid concentration in baby spinach. The largest effect was found when radiation was most intense. The nettings then decreased total flavonoid concentration by 15–24% at the normal commercial growth stage at harvest. Radiation and plant growth both affected flavonoid concentration, in opposite or similar directions depending on time of season. This variation was reflected in the statistical analysis, showing significant interactions among the factors. There were large differences (up to 100%) in flavonoid concentration between the different times of the season, in shaded as well as unshaded spinach. Flavonoid concentration and composition changed during storage, but no consistent difference was found between the shaded and unshaded leaves. In most cases, total flavonoid concentration increased significantly during the first 6 days of storage. In conclusion, the use of shade netting is acceptable for production of baby spinach as regards flavonoid concentration and composition. Copyright © 2007 Society of Chemical Industry

Performance analysis of a simple roof cooling system with irrigated soil and two shading alternatives

The use of passive cooling on roofs holds a significant unfulfilled potential in hot-arid regions. In this study, the contribution of a watered soil with two types of shading for roof cooling was assessed. Two test cells of approximately 4 m 2 in area and 2.5 m high were monitored during the summer season. Both cells were covered with a 16-cm layer of soil. One was untreated while the other was watered and shaded consecutively by means of an overhead shading mesh and a layer of lightweight gravel. Temperature profiles were measured across the section of each roof, from the top surface of the soil to the ceiling inside the chamber, and embedded heat flux plates were also used to evaluate the cooling effect. A comparison of the two shading strategies demonstrated that while the mesh provided more cooling over a daily cycle, the daytime cooling potential, which is crucial in a desert climate, was higher with lightweight gravel.

The contribution of cacao agroforests to the conservation of lower canopy ant and beetle diversity in Indonesia

The ongoing destruction of tropical rainforests has increased the interest in the potential value of tropical agroforests for the conservation of biodiversity. Traditional, shaded agroforests may support high levels of biodiversity, for some groups even approaching that of undisturbed tropical forests. However, it is unclear to what extent forest fauna is represented in this diversity and how management affects forest fauna in agroforests. We studied lower canopy ant and beetle fauna in cacao agroforests and forests in Central Sulawesi, Indonesia, a region dominated by cacao agroforestry. We compared ant and beetle species richness and composition in forests and cacao agroforests and studied the impact of two aspects of management intensification (the decrease in shade tree diversity and in shade canopy cover) on ant and beetle diversity. The agroforests had three types of shade that represented a decrease in tree diversity (high, intermediate and low diversity). Species richness of ants and beetles in the canopies of the cacao trees was similar to that found in lower canopy forest trees. However, the composition of ant and beetle communities differed greatly between the agroforest and forest sites. Forest beetles suffered profoundly from the conversion to agroforests: only 12.5% of the beetle species recorded in the forest sites were also found in the agroforests and those species made up only 5% of all beetles collected from cacao. In contrast, forest ants were well represented in agroforests, with 75% of all species encountered in the forest sites also occurring on cacao. The reduction of shade tree diversity had no negative effect on ants and beetles on cacao trees. Beetle abundances and non-forest ant species richness even increased with decreasing shade tree diversity. Thinning of the shade canopy was related to a decrease in richness of forest ant species on cacao trees but not of beetles. The contrasting responses of ants and beetles to shade tree management emphasize that conservation plans that focus on one taxonomic group may not work for others. Overall ant and beetle diversity can remain high in shaded agroforests but the conservation of forest ants and beetles in particular depends primarily on the protection of natural forests, which for forest ants can be complemented by the conservation of adjacent shaded cacao agroforests.

The Role of Leaf Lobation in Elongation Responses to Shade in the Rosette-forming Forb Serratula tinctoria (Asteraceae)

Lobed leaves are considered selectively advantageous in conditions of high irradiance. However, most studies have involved woody species, with only a few considering the role of leaf lobation in herbaceous rosette species. In this study, it is hypothesized that, in addition to its adaptive value in high light, leaf lobation may add to the function of petioles as vertical spacers in herbaceous species in conditions of strong competition for light. To test this hypothesis, leaf development was examined under seasonally changing natural light conditions and a field experiment was conducted in which light climate was manipulated in a wooded meadow population of Serratula tinctoria. No changes in leaf lobation were observed in response to experimental shading or different natural light conditions. However, in tall herbaceous vegetation, plants with highly lobed leaves achieved significantly greater vertical elongation than plants with less-lobed leaves. In contrast to herbaceous shade, tree shade had no effect on leaf elongation, suggesting differential responsiveness to competition from neighbouring herbs versus overhead shade. In shading treatments, imposed shade could only be responded to by the elongation of leaves that were produced late in development. The results show that extensive leaf lobation can enable greater leaf elongation in response to shade from surrounding herbaceous vegetation. The different morphological responses displayed by Serratula tinctoria to different types of shade demonstrate the importance of critically assessing experimental designs when investigating phenotypic plasticity in response to shade.

Interaction of red to far red light ratio and ethylene in regulating stem elongation of Helianthus annuus

Sunflower (Helianthus annuus L.) stems showed increased elongation under two types of vegetative shade: canopy shade (low red to far red [R/FR] ratio) and neighbouring proximity shade (FR enrichment). Hypocotyls also elongated more under narrow-band FR light than under narrow-band R light. Ethylene levels were determined in actively elongating 7-day-old hypocotyls and 17-day-old internodes under three R/FR ratios. Ethylene levels were lower in both sunflower hypocotyls and internodes when the R/FR ratio was reduced. Both FR enrichment of normal R/FR ratio and narrow-band FR light with very low light irradiance resulted in reduction in ethylene levels in 7-day-old hypocotyls. Further, in application experiments, sunflower stems grown under low R/FR ratio were more sensitive to ethephon and less sensitive to aminoethoxyvinylglycine (AVG) than stems grown under high R/FR ratio. Low R/FR ratio appears to initiate reduction in ethylene levels in sunflower seedlings, allowing maximum stem elongation. These results, and findings of other authors, suggest that various plant species may have developed different ways of regulating stem elongation and ethylene levels in response to low R/FR ratio.

Findings from a survey on the current use of daylight simulations in building design

This paper presents findings from a web-based survey on the current use of daylight simulations in building design. The survey was administered from December 2nd 2003 to January 19th 2004. One hundred and eighty five individuals from 27 countries completed the survey. The majority of respondents worked in Canada (20%), the United States (20%), and Germany (12%). Most participants were recruited through building simulation mailing lists. Their self-reported professions ranged from energy consultants and engineers (38%) to architects and lighting designers (31%) as well as researchers (23%). They worked predominantly on large and small offices and schools. Ninety one percent of respondents included daylighting aspects in their building design. Those who did not consider daylighting blamed lack of information and unwillingness of clients to pay for this extra service. Among those participants who were considering daylighting 79% used computer simulations. This strong sample bias towards computer simulations reflects that many participants had been recruited through building simulation mailing lists. Participants named tools’ complexity and insufficient program documentation as weaknesses of existing programs. Self-training was the most common training method for daylight simulation tools. Tool usage was significantly higher during design development than during schematic design. Most survey participants used daylighting software for parameter studies and presented the results to their clients as a basis for design decisions. While daylight factor and interior illuminances were the most commonly calculated simulation outputs, shading type and control were the most common design aspects influenced by a daylighting analysis. The use of scale model measurements had rapidly fallen compared to a 1994 survey, whereas, trust in the reliability of daylighting tools has risen. While participants named a total of 42 different daylight simulation programs that they routinely used, over 50% of program selections were for tools that use the RADIANCE simulation engine, revealing the program's predominance within the daylight simulation community.

A Uniform Sky Illumination Model to Enhance Shading of Terrain and Urban Areas

Users of geographic information systems (GIS) usually render terrain using a point light source defined by an illumination vector. A terrain shaded from a single point provides good perceptual cues to surface orientation. This type of hill shading, however, does not include any visual cues to the relative height of surface elements. We propose shading the terrain under uniform diffuse illumination, where light arrives equally from all directions of a theoretical sky surrounding the terrain. Surface elements at lower elevations tend to have more of the sky obscured from view and are thus shaded darker. This tinting approach has the advantage that it provides more detailed renderings than point source illumination. We describe two techniques of computing terrain shading under uniform diffuse illumination. One technique uses a GIS–based hill-shading and shadowing tool to combine many point source renderings into one approximating the terrain under uniform diffuse illumination. The second technique uses a C++ computer algorithm for computing the inclination to the horizon in all azimuth directions at all points of the terrain. These virtual horizons are used to map sky brightness to the rendering of the terrain. To evaluate our techniques, we use two Digital Elevation Models (DEMs)—of the Schell Creek Range of eastern Nevada and a portion of downtown Houston, Texas, developed from Light Detection and Ranging (lidar) data. Renderings based on the uniform diffuse illumination model show more detailed changes in shading than renderings based on a point source illumination model.