波段组landsat3，2，1这种RGB组合模拟出一副自然色的图象。
有时用于海岸线的研究和烟柱的探测。
4，5，3用于土壤湿度和植被状况的分析。
也很好的用于内陆水体和陆地/水体边界的确定。
4，3，2红外假色。
在植被、农作物、土地利用和湿地分析的遥感方面，这是最常用的波段组合。
7，4，2土壤和植被湿度内容分析；内陆水体定位。
植被显示为绿色的阴影。
5，4，3城镇和农村土地利用的区分；陆地/水体边界的确定。
4，5，7探测云，雪和冰（尤其在高维度地区）。
4－3/4＋3NDVI－标准差植被指数；TM波段4：3的不同比率被证明在增强不同植被类型对比度方面很有用。
实践应用3，2，1普通色图象。
适宜于浅海探测作图。
4，3，2红外色图象。
提供中等的空间分辨率。
在这种组合中，所有的植被都显示为红色。
MultiSpec3-ch.Default。
7，5，4适宜于湿润地区。
提供了最大的空间分辨率。
7，4，2适宜于温带到干旱地区。
提供最大的光谱多样性。
321：真彩色合成，即3、2、1波段分别赋予红、绿、蓝色，则获得自然彩色合成图像，图像的色彩与原地区或景物的实际色彩一致，适合于非遥感应用专业人员使用。
432：标准假彩色合成，即4、3、2波段分别赋予红、绿、蓝色，获得图像植被成红色，由于突出表现了植被的特征，应用十分的广泛，而被称为标准假彩色。
举例：卫星遥感图像示蓝藻暴发情况我们先看一看蓝藻爆发时遥感监测机理。
蓝藻暴发时绿色的藻类生物体拌随着白色的泡沫状污染物聚集于水体表面，蓝藻覆盖区的光谱特征与周围湖面有明显差异。
由于所含高叶绿素A的作用，蓝藻区在LandsatTM2波段具有较高的反射率，在TM3波段反射率略降但仍比湖水高，在TM4波段反射率达到最大。
因此，在TM4（红）、3（绿）、2（蓝）假彩色合成图像上，蓝藻区呈绯红色，与周围深蓝色、蓝黑色湖水有明显区别。
此外，蓝藻暴发聚集受湖流、风向的影响，呈条带延伸，在TM图像上呈条带状结构和絮状纹理，与周围的湖水面也有明显不同。
451：信息量最丰富的组合，TM图像的光波信息具有3～4维结构，其物理含义相当于亮度、绿度、热度和湿度。
在TM7个波段光谱图像中，一般第5个波段包含的地物信息最丰富。
3个可见光波段（即第1、2、3波段）之间，两个中红外波段（即第4、7波段）之间相关性很高，表明这些波段的信息中有相当大的重复性或者冗余性。
第4、6波段较特殊，尤其是第4波段与其他波段的相关性得很低，表明这个波段信息有很大的独立性。
计算各种组合的熵值的结果表明，由一个可见光波段、一个中红外波段及第4波段组合而成的彩色合成图像一般具有最丰富的地物信息，其中又常以4，5，3或4，5，1波段的组合为最佳。
第7波段只是在探测森林火灾、岩矿蚀变带及土壤粘土矿物类型等方面有特殊的作用。
最佳波段组合选出后，要想得到最佳彩色合成图像，还必须考虑赋色问题。
人眼最敏感的颜色是绿色，其次是红色、蓝色。
因此，应将绿色赋予方差最大的波段。
按此原则，采取4、5、3波段分别赋红、绿、蓝色合成的图像，色彩反差明显，层次丰富，而且各类地物的色彩显示规律与常规合成片相似，符合过去常规片的目视判读习惯。
例如把4、5两波段的赋色对调一下，即5、4、3分别赋予红、绿、蓝色，则获得近似自然彩色合成图像，适合于非遥感应用专业人员使用。
741：波段组合图像具有兼容中红外、近红外及可见光波段信息的优势，图面色彩丰富，层次感好，具有极为丰富的地质信息和地表环境信息；而且清晰度高，干扰信息少，地质可解译程度高，各种构造形迹（褶皱及断裂）显示清楚，不同类型的岩石区边界清晰，岩石地层单元的边界、特殊岩性的展布以及火山机构也显示清楚。
742：1992年，完成了桂东南金银矿成矿区遥感地质综合解译，利用1：10万TM7、4、2假彩色合成片进行解译，共解译出线性构造1615条，环形影像481处,并在总结了构造蚀变岩型、石英脉型、火山岩型典型矿床的遥感影像特征及成矿模式的基础上，对全区进厅成矿预测，圈定金银A类成矿远景区2处，B类4处，C类5处。
为该区优选找矿靶区提供遥感依据。
743：我国利用美国的陆地卫星专题制图仪图像成功地监测了大兴安岭林火及灾后变化。
这是因为TM7波段（2.08-2.35微米）对温度变化敏感；TM4、TM3波段则分别属于红外光、红光区，能反映植被的最佳波段，并有减少烟雾影响的功能；同时TM7、TM4、TM3（分别赋予红、绿、蓝色）的彩色合成图的色调接近自然彩色，故可通过TM743彩色合成图的分析来指挥林火蔓延与控制和灾后林木的恢复状况。
754：对不同时期湖泊水位的变化，也可采用不同波段，如用陆地卫星MSS7，MSS5，MSS4合成的标准假彩色图像中的蓝色、深蓝色等不同层次的颜色得以区别。
从而可用作分析湖泊水位变化的地理规律。
541：XX开发区砂石矿遥感调查是通过对陆地卫星TM最佳波段组fefee7合的选择（TM5、TM4、TM1）以及航空、航天多种遥感资料的解译分析进行的，在初步解译查明调查区第四系地貌。
例如把4、5两波段的赋色对调一下，即5、4、3分别赋予红、绿、蓝色，则获得近似自然彩色合成图像，适合于非遥感应用专业人员使用。
543：波段选取及主成份分析我们的研究采用1995年8月2日的TM数据。
对于屏幕显示和屏幕图象分析，选用信息量最为丰富的5、4、3波段组合配以红、绿、兰三种颜色生成假彩色合成图像，这个组合的合成图像不仅类似于自然色，较为符号人们的视觉习惯，而且由于信息量丰富，能充分显示各种地物影像特征的差别，便于训练场地的选取，可以保证训练场地的准确性；对于计算机自动识别分类，采用主成分分析（K-L变换）进行数据压缩，形成三个组分的图像数据，用于自动识别分类。
该项工作是采用以遥感图像解译为主结合地质、物化探资料进行研究的综合方法。
解译为目视解译，解译的遥感图像有：以1984年3月成像经处理放大为1：5万卫星TM假彩色片（5、4、3波段合成）和1979年7月拍摄的1：1.6万黑白航片为主要工作片种；采用1986年11月的1：10万TM假彩色片（7、4、2波段合成）为参考片种。
453：本研究遥感信息源是中国科学院卫星遥感地面接收站于1995年10月接收美国MSS卫星遥感TM波段4(红)、波段5(绿)、波段3(蓝)CCT磁带数据制作的1∶10万和1∶5万假彩色合成卫星影像图。
图上山地、丘陵、平原台地等喀斯特地貌景观及各类用地影像特征分异清晰。
成像时期晚稻接近收获，且稻田中不存积水，因此耕地类型中的水田色调呈粉红色；旱地由于作物大多收获，且土壤水分少而呈灰白色；菜地则由于蔬菜长势好，色调鲜亮并呈猩红色。
园地色调呈浅褐色，且地块规则整齐、轮廓清晰。
林地中乔木林色调呈深褐色，而分布于喀斯特山地丘陵等地区的灌丛则呈黄到黄褐色。
牧草地大多呈黄绿色调。
建设用地中的城镇呈蓝色；公路呈线状，色调灰白；铁路呈线条状，色调为浅蓝；机场跑道为蓝色直线，背景草地呈蓝绿色；在建新机场建设场地为白色长方形；备用旧机场为白色色调，外形轮廓清晰、较规则。
水库和河流则都呈深蓝色调。
采取4、5、3波段分别赋红、绿、蓝色合成的图像，色彩反差明显，层次丰富，而且各类地物的色彩显示规律与常规合成片相似，符合过去常规片的目视判读习惯。
472：在采用TM4、7、2波段假彩色合成和1:4计算机插值放大技术方面，在制作1:5万TM影像图并成1:5万工程地质图、塌岸发展速率的定量监测以及在单张航片上测算岩(断)层产状等方面，均有独到之处。
三.类型提取:1.城市与乡镇的提取:TM1+TM7+TM3+TM5+TM6+TM2-TM42.乡镇与村落:TM1+TM2+TM3+TM6+TM7-TM4-TM53.河流的提取:TM5+TM6+TM7-TM1-TM2-TM44.道路的提取：ＴＭ６－（ＴＭ１＋ＴＭ２＋ＴＭ３＋ＴＭ４＋ＴＭ５＋ＴＭ７）四．光谱差异ＴＭ１居民地与河流菜地不易分开．ＴＭ２居民地与河流菜地不易分ＴＭ３乡村与菜地不易分ＴＭ４农田与道路不易分，乡镇，道路，河滩易浑．ＴＭ５县城与农田不易分ＴＭ６村庄与河流易混首先来了解假彩色图像与其它影像的区别，通常在RS中单波段或全色波段表现为黑白图像，黑白图像的质量一般用“灰阶”来度量。
三波段组合表现为彩色影像包括：真彩色(true color)：（三波段组合），分别对RGB三个波段的图像赋予RGB三种颜色，一一对应，合成后图像的色彩与原地区或景物的实际色彩一致，称为真彩色，真彩色是唯一的合成。
伪彩色(pseudo color)：将黑白图像变换为彩色图像，对不同的灰度或灰度范围按值赋予不同的颜色或一个颜色系列，得到图像的彩色与实际彩色则不一致，即伪彩色图像。
假彩色(false color)：（三波段组合），对得来不同波段图像分别赋予RGB三元色，并不与原来波段的RGB三个波段一一对应，得到图像的彩色与实际彩色则不一致，称为假彩色图像，假彩色图像是为了使一些地物的特征更加明显，有助于我们进行解译和分析。
下面就以ETM+图像为例来谈谈假彩色图像主要应用TM各波段技术参数见下表，任意三个波段（除过321组合）的不同组合形成不同的假彩色表现形式和不同的应用：Landsat 7(ETM+sensor)Wavelength (micrometers)Resolution (meters)Band 10.45-0.51530Band 20.525-0.60530Band 30.63-0.6930Band 40.75-0.9030Band 51.55-1.7530Band 610.40-12.560Band 72.09-2.3530Pan Band .52-.9015Ground FeatureBands Used Contrast Manipulation Limits Water1,2,3;1,2,4;1,4,5No No Urban1,2,3;1,4,5Yes band 4(1,4,5)Yes band 4(1,4,5)Farmland1,2,3;1,4,5Yes band 4(1,4,5)Yes band 4(1,4,5)Forest1,2,3;1,4,5Yes band 4(1,4,5)Yes band 4(1,4,5)Salt Scald1,2,3;1,4,5Yes band 4(1,4,5)Yes band 4(1,4,5)Scrub1,4,5Yes band 4(1,4,5)Yes band 4(1,4,5)Parks/Golf 1,2,3No No Land Cover TypeSpectral Band Combination WaterBand 1,4&7/Band 1,2&3UrbanBand 1,4&7FarmlandBand 1,2&3ForestBand 1,4&7Salt Scald Band 1,2&3Landsat 5(TM sensor)Wavelength (micrometers)Resolution (meters)Band10.45-0.5230Band20.52-0.6030Band30.63-0.6930Band40.76-0.9030Band5 1.55-1.7530Band610.40-12.50120Band 7 2.08-2.3530Remnant Vegetation Band1,4&7 Irrigated Vegetation Band1,4&7 Terrain Feature Reflectance ResponseWater Bodies Generally reflect high in the visible spectrum,however,clearer water has less reflectance than turbid water. In the Near IR and Mid-IR regions water increasingly absorbs the light making it darker. This is dependent upon water depth and wavelength. Increasing amounts of dissolved inorganic materials in water bodies tend to shift the peak of visible reflectance toward the red region from the green region(clearer water)of the spectrum.Soil Northern latitudes have black soils and tropical regions have red soils. Soil reflectancedecreases as organic matter increases. As soil moisture increases,reflectance of soildecreases at all wavelengths. Texture of soil will cause increased reflectance with decreasedparticle size,i.e.,the bigger particles(rocks,sand,and soils)basically cast a larger shadow.Vegetation The spectral reflectance is based on the chlorophyll and water absorption in the leaf.Needles have a darker response than leaves. There will be various shades of vegetationbased on type,leaf structure,moisture content and health of the plant.Man-Made Materials Concrete and asphalt both display spectral curves that generally increase from the visiblethrough the Near IR and Mid-IR regions. However,as concrete ages,it becomes darker andas asphalt ages it becomes lighter.Snow and Ice Old snow may develop a compacted crust and the moisture content increases which make itless reflective in the Near IR and Mid-IR region. It is possible to compare old and newsnow by its Mid-IR reflectance.R,G,BPotential Information Content4,3,2The standard"false color"composite. Vegetation appears in shades of red,urban areas are cyan blue,and soils vary from dark to light browns. Ice,snow and clouds are white or light cyan. Coniferous trees will appear darker red than hardwoods. This is a very popular band combination and is useful for vegetation studies,monitoring drainage and soil patterns and various stages of crop growth. Generally,deep red hues indicate broad leaf and/or healthier vegetation while lighter reds signify grasslands or sparsely vegetated areas. Densely populated urban areas are shown in light blue. This TM band combination gives results similar to traditional color infrared aerial photography.3,2,1The"natural color"band combination. Because the visible bands are used in this combination,ground features appear in colors similar to their appearance to the human visual system,healthy vegetation is green, recently cleared fields are very light,unhealthy vegetation is brown and yellow,roads are gray,andshorelines are white. This band combination provides the most water penetration and superior sedimentand bathymetric information. It is also used for urban studies. Cleared and sparsely vegetated areas arenot as easily detected here as in the451or432combination. Clouds and snow appear white and aredifficult to distinguish. Also note that vegetation types are not as easily distinguished as the451combination. The321combination does not distinguish shallow water from soil as well as the753 combination does.7,4,2This combination provides a"natural-like"rendition,while also penetrating atmospheric particles and smoke. Healthy vegetation will be a bright green and can saturate in seasons of heavy growth,grasslands will appear green,pink areas represent barren soil,oranges and browns represent sparsely vegetated areas. Dry vegetation will be orange and water will be blue. Sands,soils and minerals are highlighted in a multitude of colors. This band combination provides striking imagery for desert regions. It is useful for geological,agricultural and wetland studies. If there were any fires in this image they would appear red. This combination is used in the fire management applications for post-fire analysis of burned and non burned forested areas. Urban areas appear in varying shades of magenta. Grasslands appear as light green. The light-green spots inside the city indicate grassy land cover-parks,cemeteries,golf courses. Olive-green to bright-green hues normally indicate forested areas with coniferous forest being darker green than deciduous.4,5,1Healthy vegetation appears in shades of reds,browns,oranges and yellows. Soils may be in greens and browns,urban features are white,cyan and gray,bright blue areas represent recently clearcut areas andreddish areas show new vegetation growth,probably sparse grasslands. Clear,deep water will be very dark in this combination,if the water is shallow or contains sediments it would appear as shades of lighter blue.For vegetation studies,the addition of the Mid-IR band increases sensitivity of detecting various stages ofplant growth or stress;however care must be taken in interpretation if acquisition closely followsprecipitation. Use of TM4and TM5shows high reflectance in healthy vegetated areas. It is helpful tocompare flooded areas and red vegetated areas with the corresponding colors in the321combination toassure correct interpretation. This is not a good band combination for studying cultural features such asroads and runways.4,5,3This combination of near-IR(Band4),mid-IR(Band5)and red(Band3)offers added definition of land-water boundaries and highlights subtle details not readily apparent in the visible bands alone. Inland lakesand streams can be located with greater precision when more infrared bands are used. With this bandcombination,vegetation type and condition show as variations of hues(browns,greens and oranges),as wellas in tone. The4,5,3combination demonstrates moisture differences and is useful for analysis of soil andvegetation conditions. Generally,the wetter the soil,the darker it appears,because of the infraredabsorption capabilities of water.7,5,3This band combination also provides a"natural-like"rendition while also penetrating atmospheric particles, smoke and haze. Vegetation appears in shades of dark and light green during the growing season,urban features are white,gray,cyan or purple,sands,soils and minerals appear in a variety of colors. The almost complete absorption of Mid-IR bands in water,ice and snow provides well defined coast lines and highlighted sources of water within the image. Snow and ice appear as dark blue,water is black or dark blue. Hot surfaces such as forest fires and volcano calderas saturate the Mid-IR bands and appear in shades of red or yellow. One particular application for this combination is monitoring forest fires. During seasons of little vegetation growth the742combination should be substituted. Flooded areas should look very dark blue or black,compared with the321combination in which shallow flooded regions appear gray and are difficult to distinguish.5,4,3Like the451combination,this combination provides the user with a great amount of information and color contrast. Healthy vegetation is bright green and soils are mauve. While the742combination includesTM7,which has the geological information,the543combination uses TM5which has the mostagricultural information. This combination is useful for vegetation studies,and is widely used in the areasof timber management and pest infestation.5,4,1This will look similar to the742combination in that healthy vegetation will be bright green,except the541 combination is better for agricultural studies.7,5,4This combination involves no visible bands. It provides the best atmospheric penetration. Coast lines and shores are well defined. It may be used to find textural and moisture characteristics of soils.Vegetation appears blue. If the user prefers green vegetation,a745combination should be substituted.This band combination can be useful for geological studies.5,3,1This combination display topographic textures while731may display differences in rock types.Landsat Thematic Mapper(TM)Band1(0.45-0.52u m):provides increased penetration of water bodiesand also capable of differentiating soil and rock surfaces from vegetation andfor detecting cultural features.Band2(0.52-0.60u m):it is sensitive to water turbidity differences;it highlighted the turbid water in the Barkley Lake.Because it covers the green reflectance peak from leaf surfaces,it has separated vegetation(forest,croplands with standing crops)from soil.In this band barren lands urbanareas and roads and highways have appeared as brighter(lighter)tone,but forest,vegetation,bare croplands,croplands with standing crops haveappeared as dark(black)tone.Also the Kentucky Lake has appeared asblack tone.Band3(0.63-0.69u m):senses in a strong chlorophyll absorption regionand strong reflectance region for most soils.It has discriminated vegetationand soil.But it couldn t separated water and forest.Forest land and waterboth have appeared as dark tone.This band has highlighted barren lands,urban areas,street pattern in the urban area and highways.It has alsoseparated croplands with standing crops from bare croplands with stubble.Band4(0.76-0.90u m):operates in the best spectral region todistinguish vegetation varieties and conditions.Because water is a strongabsorber of near IR,this band has delineated water bodies(lakes and sinkholes),distinguished between dry and moist soils(barren land and croplands).In this band croplands and grasslands have showed higherreflectance(brighter tone)than the forest.This band has also separatedcroplands from bare croplands.Since standing crops(vegetation)has higher reflectance in the near IR region,they have appeared as brighter tone and due to presence of moisture content in the bare croplands,they have appeared as darker tone.In the band4barren lands,urban areas and highways have not been highlighted and they appeared as dark tone.Band4 is useful for crop identification and emphasizes soil-crop and land-water contrast.Band5(1.55-1.75u m):is sensitive to the turgidity or amount of waterin plants.Band5has separated forest lands,croplands,water body distinctly. Forests have appeared as comparatively darker tone than the croplands (light gray).Band5has separated water body(dark tone)from barren lands, croplands,and grass lands(lighter tone).Since urban area and croplands have responded almost in same spectral reflectance band5could not beable to separate these areas.Band7(2.08-2.35u m):has separated land and water sharply.Band7has strong water absorption region and strong reflectance region for soil and rock.Urban area,croplands,highways,bare croplands have appeared as bright tone and water body,forest have appeared as dark tone.Ratio transformations of the remotely sensed data can be applied to reduce the effects of environment. Ratios also provide unique information and subtle spectral-reflectance or color differences between surfacematerials that are often difficult to detect in a standard image.It is alsouseful for discriminating between soils and vegetation.The number of possible ratio combinations for a multispectral sensor with P bands is n=P(P-1). Thus for the TM s six reflectance bands there arethirty different ratio combinations-15original and15reciprocal.For the purpose of this study ten band ratios were examined to identify the LULC features.TM3/TM4:This ratio has defined barren lands and urban area uniquely.But it could not define water body,forests and croplands.TM4/TM3:This ratio distinguished vegetation,water and croplands.It has enhanced forests,barren lands.Because forests or vegetation exhibitshigher reflectance in near IR region(0.76-0.90u m)and strong absorptionin red region(0.63-0.69u m)region.This ratio uniquely defines the distribution of vegetation.The lighter the tone,the greater the amount of vegetation present.TM5/TM7:This ratio separated land and water uniquely.Since soils exhibit strong absorption in the band7(2.08-2.35u m)and high reflectance in band5(1.55-1.75u m),soil has been enhanced in this nd has appeared as lighter tone and water appeared as dark tone.TM2/TM3:this ratio has distinguished croplands,barren lands sharply.But it hasn t separated croplands,forests and water body.Both forests and water body has appeared as lighter tone and barren land appeared has dark tone.It did not enhance urban area.Chlorophyll has strong reflectance inthe band2(0.52-0.60u m)region and strong absorption in the band3(0.63 -0.69u m)region,vegetation has appeared as higher tone.TM3/TM2:This ratio has separated forests and croplands.Because band3 (0.63-0.69m m)is the red chlorophyll absorption band of healthy green vegetation and band2(0.52-0.69m m)is the reflectance band from leaf surfaces.This ratio can be useful to discriminate broad classes of vegetation. Croplands have appeared as lighter(brighter)tone and forests appeared as dark tone.TM4/TM5:It enhances the water body,vegetation and presence of moisture content in the croplands.Water body has appeared as dark tone and vegetation as lighter tone.Because water is a strong absorber in near IR region(band4)and higher reflectance in band5region.It can be useful for discriminating water bodies from land.TM5/TM4:It has separated water body from forest,barren lands and vegetation.In this ratio water has appeared as dark tone and forest,barren lands,bare croplands all have exhibited brighter tone.TM5/TM7:It has separated water body from lands(soils).It has also enhanced presence of moisture in croplands.All water bodies appeared as dark tone.Both band5and band7are sensitive to moisture content variation in soils and vegetation.This ratio is useful for crop-drought studies and plant vigor investigations.TM3/TM5:This ratio enhances barren lands,highways,street patterns within the urban areas and urban built-up or cemented areas.It could not enhance the clear water but it enhanced turbid water.This ratio is useful for observing differences in water turbidity.Barren lands,highways,urban and built-up areas have appeared as lighter tone and forests,water body and croplands appeared as dark tone.TM7/TM2:This ratio has separated forests and croplands.But it could not separated forests from water body;both features have appeared as darktone.It enhances highways,urban and built-up areas and croplands and all of them have appeared as lighter tone.。