Small intestinal bacterial overgrowth1

REVIEW ARTICLE

Small intestinal bacterial overgrowth

S.V .RANA 1&S.B.BHARDWAJ 2

1Department of Gastroenterology,Postgraduate Institute of Medical Education and Research,Chandigarh,India,and 2

Department of Microbiology,DR H.S.J Institute of Dental Sciences and Hospital,Punjab University,Chandigarh,India

Abstract

Small intestinal bacterial overgrowth (SIBO)syndrome is characterized in its florid form by diarrhoea and weight loss.The most common underlying factors are dysmotility,small intestinal obstruction,blind or afferent loops.Small intestinal bacterial overgrowth can be diagnosed by:1)culture of jejunum aspirate for bacterial counts,2)14C-D-xylose breath testing,3)non-invasive hydrogen breath testing using glucose or lactulose or 4)14C-glycocholic acid breath testing.The treatment usually consists of the eradication of bacterial overgrowth with repeated course of antimicrobials,correction of associated nutritional deficiencies and,when possible,correction of the underlying predisposing conditions.

Key Words:Bacterial overgrowth,hydrogen breath test,small intestine

Introduction

Small intestinal bacterial overgrowth (SIBO)is characterized by nutrient malabsorption associated with an excessive number of bacteria in the proximal small intestine.The pathology of this condition involves competition between bacteria and the hu-man host for ingested nutrients.This competition leads to intraluminal bacterial catabolism of nutri-ents,often with production of toxic metabolites and injury to the enterocytes.A complex array of clinical symptoms ensues,resulting in chronic diar-rhoea,bloating,flatulence,abdominal pain,nausea and weight loss [1,2].SIBO is commonly present in the elderly,who may have motility disturbance [3],and in chronic pancreatitis [4],chronic renal failure [5]and cirrhosis of the liver [6].Aetiology

In healthy persons in the Tropics,the proximal small bowel has approximately 107organisms/ml of jejunal aspirate,mainly Gram-positive aerobic organisms [7].In SIBO,excessive numbers of Gram-negative aerobes and anaerobes colonize.In the Tropics,SIBO has been characterized by an

abnormally high bacterial population level in the upper gut exceeding 107organisms/ml jejunal aspi-rate,i.e.7log colony forming units (CFU)/ml jejunum aspirate [8].SIBO has also been defined as a clinical condition caused by an increased level of microorganisms exceeding the presence of more than 104or 106CFU/ml of intestinal aspirate or more colonic type bacteria within the small intestine [8,9].In one study [10],jejunal samples of patients with diarrhoea and conditions predisposing to SIBO were cultured.The main bacteria recovered were Strepto-coccus (71%),Escherichia coli (69%),Staphylococcus (25%),Micrococcus (22%),Klebsiella (20%),Proteus (11%)for microaerophilic bacteria,and Lactobacillus (75%),Bacteroides (29%),Clostridium (25%),V eillo-nella (25%),Fusobacterium (13%),Peptostreptococcus (13%)for anaerobic bacteria.The excess bacteria classically produce diarrhoea and malabsorption by deconjugating bile acids,rendering them inadequate for micellar formation and fat digestion,and there-fore there may not be any villous atrophy present [11].The following are the predisposing factors for SIBO:

(i)Farnesoid X receptor :Recent research has shown that the farnesoid X receptor (FXR),a nuclear

Correspondence:S.V .Rana,House no.137,Sector 15-A,Chandigarh 160015,India.Tel:'911722716417.Fax:'911722744401.E-mail:svrana25@https://www.360docs.net/doc/f816422098.html,

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S c a n d J G a s t r o e n t e r o l D o w n l o a d e d f r o m i n f o r m a h e a l t h c a r e .c o m b y F r a n c i s A C o u n t w a y L i b r a r y o f M e d i c i n e o n 12/29/12F o r p e r s o n a l u s e o n l y .

receptor for bile acids,induces genes involved in enter protection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation.Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier [12].These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow.

(ii)Achlorhydria :Achlorhydria is known to be a predisposing factor for SIBO.It has been described in patients after taking proton-pump inhibitors (PPIs),but clinical malabsorption does not appear to occur in this situation [13].Drug-induced hypo-chlorhydria causes high duodenal bacterial counts in the elderly,but in the short term this bacterial overgrowth is not associated with malabsorption [14].

(iii)Old age :SIBO has been reported in asympto-matic elderly persons residing in the community.These patients,although asymptomatic,had lower weights and body mass index (BMI)than expected,and treatment with antibiotics increased both weight and BMI [15].Studies indicate that SIBO is seen only in patients with intestinal disease and disabled or frail older people [16].In older people,SIBO has been cited as an important and under-recognized cause of malnutrition [17].Risk factors for bacterial overgrowth,such as reduction in intestinal motility,small-bowel diverticulosis,previous intestinal sur-gery and achlorhydria,are all more prevalent in an older population [18].Gastric hypochlorhydria and bacterial colonization with mainly Gram-positive flora (in the upper gut)may be present in up to 80%of healthy old people [19].SIBO,as documen-ted by a glucose hydrogen breath test,has been reported previously in 14.5á15.5%of unselected asymptomatic care home residents [20].

(iv)Liver cirrhosis :SIBO in cirrhosis is associated with systemic endotoxemia [21].Several studies have documented the importance of bacterial trans-location in cirrhosis and it appears to play a role in the pathogenesis of spontaneous bacterial peritonitis (SBP)[4,22].Disruption of the gut flora equilibrium is related to the development of bacterial transloca-tion [23].Several studies have shown that impaired intestinal motility is one of the factors contributing to entire bacterial overgrowth and to delay of intestinal transit time in the setting of cirrhosis mainly related to severity of the disease [24].Finally,cirrhosis is associated with reduced intestinal moti-lity,which prevents normal peristaltic clearance,and this may result in enteric bacterial overgrowth and subsequent translocation [25].Impaired motility of the small intestine,carrying bacterial overgrowth of

the small intestine,may be one of the explanations for recurrent SBP in cirrhotic patients [26].

In a study in which patients with liver cirrhosis with and without portal hypertension were included,it was seen that abnormal small-bowel motility and SIBO are common in patients with liver cirrhosis with concomitant portal hypertension [26].

(v)Diabetes mellitus :Small intestinal bacterial over-growth has been reported in 43%in cases of chronic diabetic diarrhoea [27].Chronic GI symptoms in association with diabetes mellitus were reported for the first time by Rundles in 1945[28].Diabetic neuropathy and SIBO have also been reported [28].Small-bowel involvement is one of the most proble-matic complications of diabetes mellitus [29].In cases of SIBO,bacteria divert the vitamins and nutrients necessary for their own growth [30].

(vi)HIV :Opportunistic infections of the small or large bowel are the usual course of HIV-I associated diarrhoea,especially in patients with severe defi-ciency.Despite extensive diagnostic evaluation,however,the cause of diarrhoea is not identified in 15á50%of HIV-I infected patients [31].Among such patients,SIBO is an appropriate consideration,since hypochlorhydria has been reported to be common in patients with AIDS,and gastric and duodenal bacterial colonization is associated with hypochlorhydria [32].

(vii)Scleroderma :SIBO is readily recognized in scleroderma.The overgrowth occurs mainly in patients with small intestine involvement [33]and limited cutaneous systemic sclerosis.Diarrhoea is the most important symptom in this condition.

(viii)Tropical sprue :This is another condition seen in the Tropics and sub-tropical regions.It is associated with bacterial contamination of the gut with [7]or without associated malnutrition responding to anti-biotics [34].

(ix)Coeliac disease and pancreatitis :Many patients with coeliac sprue,who have persistent symptoms despite their adherence to a gluten-free diet,have SIBO [35].Small intestinal bacterial overgrowth is frequent in patients with pancreatic insufficiency,particularly in those with a history of gastroduodenal surgery [36].The positive correlation between the severity of pancreatitis,the disturbance of migrating motor complex and SIBO suggests an important pathophysiological role of proximal bowel in the infection of pancreatic necrosis [37].(x)Other conditions :

.SIBO with rheumatoid arthritis has been de-scribed.This syndrome is associated with high disease activity and does not appear to be related to achlorhydria [38].

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.SIBO occurs in late radiation enteritis and appears to be related to intestinal dysmotility and strictures as well [39].

.SIBO is common in patients with functional gastrointestinal diseases,which is associated with delayed small intestinal motility [40].Mechanism of malabsorption in SIBO

Small intestinal bacterial overgrowth classically causes a combination of megaloblastic anaemia,due to vitamin B12deficiency,and steatorrhoea,due to fat malabsorption.Megablastic anaemia was described in association with intestinal strictures as long ago as 1897[41].Anaerobic organisms are responsible mainly for the vitamin B12deficiency [42].Anaerobic bacteria deprive the host of ingested vitamin B12and cause its deficiency by using the B12to produce inactive cobamides,which then may compete with dietary B12for ileal binding sites,thereby decreasing absorption of the vitamins [43].Deficiencies of thiamine [44]and nicotinamide have also been reported in SIBO [45].

Much of our knowledge on the mechanism of malabsorption in SIBO derives from animal models of blind loop [46].Deficiencies of vitamins A,D and E have been reported,but vitamin K deficiency is uncommon because of the production of vitamin K by luminal bacteria [46].SIBO leads to carbohydrate malabsorption by reducing brush border disacchar-idase levels [47].Lactose intolerance is common and contributes to the diarrhoea that typifies SIBO.Bacterial fermentation of carbohydrates contributes to abdominal discomfort and bloating in SIBO and is the basis for various breath tests used to diagnose this condition.Protein malabsorption in SIBO is caused by a number of factors, e.g.decreased absorption of amino acids and peptides,leading to mucosal damage [48],low level of enterokinase,which may impair the activation of pancreatic proteases [49]and or protein-losing enteropathy [50].Small intestinal histological findings are gen-erally normal in patients with SIBO,but transient abnormalities of the small intestinal mucosa have been described in some patients with SIBO [51].Electron microscopic studies of experimental ani-mals with SIBO have described enterocyte abnorm-alities,such as vacuolization of the microvillus membranes and mitochondrial swelling [52].Clinical features of SIBO

The clinical presentation of SIBO is that of a malabsorptive state characterized by steatorrhoea and vitamin B12deficiency.Patients with vitamin B12deficiency may present with neurologic symp-

toms,central or peripheral neuropathy and symp-toms of anaemia,such as fatigue and breathlessness.Patients with steatorrhoea may report weight loss,diarrhoea and abdominal bloating and discomfort.Associated fat-soluble vitamin deficiency may occur,leading to night blindness (in vitamin A deficiency)and metabolic bone disease (in vitamin D defi-ciency).Osteoporosis is a well-recognized complica-tion of SIBO.Bone mineral density (BMD)in patients with SIBO has been reported to be lower [53].Although flawed in terms of patient selection and methods used to diagnose SIBO,more recent studies have demonstrated that the clinical presenta-tion in SIBO may be a less dramatic one,with milder symptoms,than the classic description of SIBO [54].It has been postulated that SIBO might play a role in the pathogenesis of NASH by altering small intestinal permeability,thereby increasing absorp-tion of endotoxin [55].Diagnosis of SIBO

The diagnosis of SIBO should be considered in any patient with malabsorption and a predisposing anatomic or functional disturbance.It is likely that SIBO is overlooked in patients without predisposing factors and in patients who have non-specific symp-toms.Blood tests in patients with SIBO typically reveal a macrocytic anaemia.Vitamin B12levels are low and folate levels may be high.Steatorrhoea may be confirmed by 3-day faecal fat collection [56].If an anatomic defect is suspected as the cause of SIBO,appropriate barium studies may be used to define the anatomy.

The following tests have been used to diagnose small intestinal bacterial overgrowth:

(i)Culture method

The gold standard test for the diagnosis of SIBO is aspiration of small intestinal fluid for culture and bacterial counts of the aspirate.According to Bhat et al.[7],the presence of more than 107CFU/ml of jejunum aspirate from tropical patients is considered diagnostic;104according to Justesen et al.[8]and 106according to Donaldson [9].Unfortunately,such aspiration of fluid is invasive and time-consum-ing.Moreover,although this is still recommended by most experts,some investigators have raised doubts that the test may miss bacterial overgrowth occurring more distally in the small intestine [57].However,collected intestinal juice at two different levels of the proximal jejunum indicated a highly significant correlation between the bacterial counts at these sites.Other potential problems with aspiration of small intestinal fluid include contamination of aspi-rate with mouth flora and technical difficulties with

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transport and culture of the aspirate.Contamination with oropharyngeal bacteria may be controlled by simultaneous culture of saliva and jejunal aspirate [58].Several techniques for collecting small intest-inal contents have been described,including jejunal intubations with fluoroscopic guidance and endo-scopic collection of fluid [59],and brushing of the duodenal mucosa with a cytology brush [60].Culture of small intestinal mucosal biopsy specimens is an alterntive to culture of aspirates [61].(ii)1H-NMR spectroscopy

In a study by Bala et al.[62],biochemicals in the upper gut aspirate in 31patients with malabsorption syndrome (MAS)with and without SIBO were analysed using high resolution H-NMR spectro-scopy and were correlated with the degree of SIBO and severity of https://www.360docs.net/doc/f816422098.html,pared to controls,the patients had higher quantities of total bile acids/cholesterol,lactate,acetate formate.However,ami-no acids and glucose were comparable in both patients and disease-free controls.In patients with MAS,the quantity of acetate positively correlated with the degree of SIBO and unconjugated bile acids correlated with the degree of steatorrhoea.This study demonstrated the bacterial production of metabolites and deconjugation of bile acids in patients with MAS.

(iii)14C-Glycocholic acid breath test

A variety of non-invasive tests have been developed for the diagnosis of SIBO.The 14C-glycocholic acid breath test was one of the first breath tests used for this purpose and is based on the ability of bacteria to deconjugate bile salts [63].14

C-glycine is produced and metabolized,result-ing in a peak of 14CO 2in the expired air.The test has a low sensitivity and low specificity [63].It therefore cannot distinguish between SIBO and ileal malab-sorption and has largely fallen out of favour.(iv)Non-invasive breath tests

The currently used breath tests are based on the ability of bacteria to produce hydrogen or radiola-belled carbon dioxide after metabolizing a substrate such as glucose,lactulose or D-xylose.Breath tests are simple and non-invasive and therefore are more attractive than duodenal intubations or endoscopy in the collection of intestinal aspirates.However,these tests do have several potential problems [64].(i)15%of the population are methane producers (in persons who are colonized with methanobrevibactor smithi,hydrogen reacts with carbon dioxide to form methane,so they produce less hydrogen than is typical for non-methane producers).(ii)Both slow and rapid small intestinal transit may affect the accuracy of these tests.(iii)An acidic environment in the colon,as occurs with ingestion of non-absorbable carbohydrates (https://www.360docs.net/doc/f816422098.html,ctulose),inhibits

bacterial carbohydrate metabolism [65].(iv)There are several patient-related factors,such as recent diet,smoking and exercise,that may influence baseline levels of breath hydrogen.The literature on breath tests in SIBO reveals wide variations in sensitivity and specificity.

The following non-invasive breath tests have been used:

1.Glucose hydrogen breath test :The glucose hydrogen breath test has been reported as a diagnostic test for SIBO [66].It is the most widely used test,as the substrate is inexpensive,and the glucose (which is absorbed in the upper small intestine during the test)is cleared by bacteria into carbon dioxide and hydrogen.Fasting breath hydrogen levels of more than 20ppm are also considered positive,but high baseline hydrogen levels are common in untreated coeliac disease and normalize after gluten with-drawal [67].A number of studies have compared the glucose hydrogen breath test against the gold standard of intestinal aspirate.Sensitivity levels from 27%to 52%have been reported with specificity rates between 30%and 83%[64].The glucose breath test appears to be an accurate,non-invasive,inexpensive diagnostic test for small bowel stricture(s)and secondary bacterial overgrowth in Crohn disease.However,in patients with cirrhosis,the glucose breath hydrogen test correlates poorly with the diagnostic gold standard for SIBO [68].

https://www.360docs.net/doc/f816422098.html,ctulose hydrogen breath test :The lactulose hydrogen breath test is based on a principle similar to that of the glucose hydrogen breath https://www.360docs.net/doc/f816422098.html,ctulose is a starch that is not absorbed by the small intestine but is cleared by bacteria in the proximal colon into hydrogen,producing a late peak in exhaled hydrogen.In the presence of bacterial overgrowth,an early hydrogen peak is observed.Results of this test may be difficult to interpret with either slow or fast intestinal transit,and sensitivity and specificity have been disappointing.The lactulose hydrogen breath test cannot be recommended for routine clinical use.

https://www.360docs.net/doc/f816422098.html,ctose hydrogen breath test :In a study by dos Reis et al.[69],the lactose absorption capacity and possible existence of bacterial overgrowth in the small bowel of asymptomatic school children was https://www.360docs.net/doc/f816422098.html,ctose malabsorption was detected in 22.9%of the children and lactose intolerance was observed in 12%.Lactose intolerance was more frequently observed in children who showed lactose malabsorption than in those who presented a normal test.Bacterial overgrowth was detected in 7.2%of the children and showed no statistical relationship with lactose malabsorption.

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(v)14C-xylose and 13C-xylose breath tests

The 14C-xylose and 13C-xylose breath tests measure labelled carbon dioxide that is produced by the breakdown of labelled substrates by bacteria.The isotope used may be radioactive (14C)or stable compound (13C).One gram D-xylose is the most widely used substrate.D-xylose is absorbed entirely in the small intestine and is metabolized minimally.It is catabolized by Gram-negative bacteria and is therefore a good substrate for breath testing for SIBO.The 14C-D-xylose breath test appears to do better than the glucose or lactulose hydrogen breath test but,as with these other breath tests,widely differing levels of accuracy have been reported,with sensitivity rates between 40%and 100%[70á75].Stotzer and Kilander [76]compared between the 1g 14C-D-xylose breath test and the 50g glucose hydrogen breath test for diagnosis of SIBO in relation to results of cultures of small-bowel aspirate.

Forty-six consecutive patients were given a solu-tion of 1g D-xylose and 50g glucose and the con-centration of breath hydrogen was analysed every 15min for 2h.The utility of hydrogen breath tests in the diagnosis of SIBO has also been described by Ghoshal et al.[77].The limitations,pitfalls and

occasional abuse of these tests can be turned into proper clinical and scientific use in the future [78].(vi)Cholyl-PABA and serum bile acid tests

Other non-invasive tests described for SIBO include measurement of Cholyl-PABA and serum bile acid.This PABA-based test,however,does not accurately distinguish between SIBO and other causes of malabsorption [79].Elevated free serum bile acids have been reported in SIBO,but the test depends on the presence of bacteria that deconjugate bile acids,such as Bacteroides [80].

Sensitivity and specificity of breath tests in the diagnosis of SIBO:

Treatment

Predisposing factors for SIBO,such as the patient’s nutritional state and any vitamin deficiency,should be corrected.Broad-spectrum antibiotics have been reported to be effective against Gram-negative aerobic and anaerobic bacteria.One randomized crossover trial reported that norfloxacin,since it is not absorbed from the intestine,and amoxycillin-clavulanate were effective agents in SIBO [84].In another study,rifaximin,a non-absorbable anti-biotic and chlortetracycline normalized results on glucose hydrogen breath testing in 70%and 27%,

T est/reference

Sensitivity (%)

Specificity (%)

Glucose breath test

Kerlin &Wong (1988)[64]9378Corazza et al.(1990)[57]6283Bauer et al.(2000)[68]

27á5236á80Stotzer &Kilander (2000)[76]5886Mishkin et al.(2002)[81]3434á96Urita et al.(2006)[82]2575Ghoshal et al.(2006)[77]4480Lactulose breath test

Ghoshal et al.(2006)[77]3186Riordan et al.(1996)[65]1770Corazza et al.(1990)[57]6844Rhodes et al.(1979)[83]89100C 14D-xylose breath test King et al.(1980)[70]

100áRumessen et al.(1985)[71]6559King &T oskes (1986)[72]95100Valdovinos et al.(1993)[73]6040Chang et al.(1995)[74]6090Lewis et al.(1997)[75]

7985Stotzer &Kilander (2000)[76]4286C 14-bile acid breath test King et al.(1980)[70]

33.3

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respectively,of patients with SIBO [85].Both ciprofloxacin and metronidazole were found to be highly effective in SIBO associated with Crohn’s disease as breath test result normalization occurred in a majority of patients in the study [86].

Few studies have examined probiotic therapy in SIBO.Saccharomyces boulardi does not appear to be effective [84],and in one double-blind crossover study Lactobacillus fermentum KLD shows no advan-tage over placebo [87].A small uncontrolled trial showed that Lactobacillus plantarum 299V and Lactobacillus GG benefited children with SIBO associated with short-bowel syndrome [88].Shimpl et al.[89]have shown that a tungsten-supplemented diet attenuates bacterial translocation in chronic portal hypertensive and cholestatic rats.Recent investigations have shown that the treatment of SIBO with enteric-coated peppermint oil is of benefit,especially in IBS [90].

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1036Review

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Review

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(完整版)新概念英语青少版(入门级A)StarterA重点知识总结

Unit 6 This is my family. 词汇：family mum dad sister brother friend 句型：This is... 句子：1.This is my mum. Lesson 2 词汇：my your 缩写：What’s=What is my name’s=my name is 句子：①What’s your name？ My name’s Pop. Unit 7 Happy birthday? 词汇：bike car doll robot train van 缩写：it’s it’s=it is it isn’t it isn’t=it is not 词汇：a an 句子：①It’s a van. ②It isn’t a car. 短语：a train/van/robot/car An apple/insect/egg/umbrella Lesson 2 句型：Is it...? 句子：㈠Is it an apple？ Yes，it is./No,it isn’t. Unit 8 That’s my book. 词汇：book, pen, pencil ,pencil case, rubber, ruler, school bag 缩写：this is this isn’t this isn’t= this is not that is that isn’t that isn’t= that is not 句子：①肯——This is my book. 否——This isn’t my book. ②肯——That’s my book. 否——That’s isn’t my book. Lesson 2 句型：Is this...? Is that...? 句子：①Is this a pencil？ Yes，it is./No,it isn’t. ②Is that a school bag? Yes，it is./No,it isn’t. Unit 9 What’s this,Mum? 词汇:bone, hamburger, salad, sausage, tomato, pizza 缩写：What’s=What is 句型：What’s...?

ArcGIS基础教程

ArcMap简介 ArcMap是创建、浏览、查询、编辑、组织和发布地图的一种工具。大多数地图都可同时显示某个地区当前的多种信息。Greenvalley市的地图中包含了三个图层：公共建筑物、街道和公园。我们可以在内容表中看到这些图层，每个图层上都有一个复选框用于图层的开启与关闭。 ArcMap内容表点要素线要素面要素在图层中，符号用来表示地理要素。在这个实例中，公共建24 筑物用点来表示，街道用线来表示，公园用面来表示。每个图层包含两种信息：描述地理要素的空间位置和形状的空间信息；描述地理要素的属性信息。在公园这一图层中，所有的公园用绿色来标记，通过这个符号可以知道那些地方是公园，但还不能据此了解不同公园之间有何差异。在街道这一图层中，不同种类的街道，用不同的线状符号来表示。这样，用不同的线状符号来区分不同的街道，就表示了不同街道之间的差异。在建筑物这一图层中，不同的建筑物用不同的点状符号来表示。点的形状和颜色可以区分各个不同的组织机构。所有的学校都被归为一类，用一种特殊的符号来表示，因此可以很容易地把学校、医院和市政大楼区分开来。每一类学校都用不同的颜色表示，就很容易把Pine初级中学和Greenvalley 高级中学区分开来。 A RC GIS 基础教程

操作地图 ArcMap提供了许多方法让你与地图进行交互操作。浏览地图可以让人们发现要素之间的空间关系。可以用刚才打开的地图查询市政大楼（City Hall）的位置，查看靠近学校的公园，或了解图书馆旁的街道的名称。分析可以通过向地图中添加图层获取新的信息和发现隐含的规律。例如，如果在Greenvalley地图中添加了人口统计信息，就可以用这张地图进行学区的划分或发现潜在的消费顾客。如果添加了地质或地表坡度的图层信息，就可以用这张地图确定可能发生山崩的危险地区。显示结果 ArcMap可以打印地图，并能将其嵌入到其他文件或电子出版物中。用户可以迅速地组织数据制作成图，保存地图时，所设计的打印版面、符号、注记和图表都同时被保存。 ArcMap中包含了一大批创建和使用地图的工具。在本章后面的内容中，用户将使用其中的一些工具。定制地图是一种很有效的工具。如果地图中包含了可对其进行编辑加工的工具，将有助于用户更快地完成工作。用户可以通过向工具条中添加或删除工具，或创建个性化的工具条，轻松地定制ArcMap的界面。这些经过定制的界面可以和地图一起保存。用户也可以运用包含在ArcMap中的编程语言工具VBA （Visual Basic for Applications）来开发新的工具和创建界面。例如，运用VBA可开发一个工具，完成在一个选定区域内制作房屋地址数据表的功能。一旦设计出某种工具，把它和定制的工具条相关联，或把这个工具和地图存储在一起，其他人就能使用这个工具了。编程为了便于同地图进行交互操作，用户可以自行设计新界面，创建特殊要素类。ArcGIS是完全组件对象模型（COM）化的，开发人员可以使用任何一种与之兼容的编程语言来制作组件。如果需要更多关于定制ArcMap和ArcCatalog的信息，可以参阅《Exploring ArcObjects》一书。浏览A RC C A TA LOG 和A RC M A P25

新概念英语青少版starterA期末练习

新概念英语青少版入门级A Listening 听力部分30’ 一、听录音，写单词，并写出单词的中文含义(20’)。二、听录音，选出你所听到的单词。（10’） 1. ( ) A. skirt B. shirt C. sock D. sweater 2. ( ) A. rabbit B. tortoise C. rubber D. parrot 3. ( ) A. twelve B. twenty C. eleven D. seven 4. ( ) A. a duck B. two ducks C. three ducks D. four ducks 5. ( ) A. evening B. morning C. lunch D. breakfast 6. ( ) A. chair B. shelf C. bed D. wall 7. ( ) A. next to B. bedroom C. bathroom D. between 8. ( ) A. dancer B. nurse C. man D.woman 9. ( ) A. aunt B. uncle C. cousin D. sister 10. ( ) A. this B. that C. those D. the

Writing 笔试部分70’ 三．用“a”或“an”填空（10’） 1. apple 2. book 3. rabbit 4.umbrella 5. mouse 6. __ ice cream 7. ___ little monkey 8. __ big egg 9. __ red apple 10．＿banana 四、圈出不同(10’) 1. red blue pink banana 2. frog mouse butterfly big 3. shirt anorak short cap 4. seven eight sister eleven 5. father mother uncle driver 五、请写出缩写（10’） I am___ he is___ you are ___ is not___ are not___ it is___ they are____ she is____ that is ____ 六、选择正确的答案（10’） ( )1.--What’s this? A. That’s a book. B. Yes, it is. C. It’s a bus. ( )2.--What colour is it? A. It’s yellow. B. It’s a dog. C. Thank you. ( )3.-- is your name? --I’m Ann. A.What B. Who C. Where

ArcGIS入门教程(1)——ArcMap应用基础

ArcGIS入门教程（1）——ArcMap应用基础实验一 ArcMap应用基础一、目的通过实验操作，掌握ArcMap软件的基础操作，主要包括地图文档打开与保存、图层显示与数据查看、简单符号化、要素标识、注记添加、地图元素添加、地图排版与打印，对ArcMap软件的基础操作加以熟悉。二、数据（1）地图文档文件（airport.mxd）；（2）源数据文件（airport.gdb），其中各图层含义如下：“Schools”表示初级、中级、高级和私立学校的位置；“Runways”表示机场跑道的位置；“Arterials”表示主干道；“Cne165”表示噪声等值线；“Airport_area”表示计划的机场扩建区；“county”表示县界。三、步骤 3.1 启动ArcMap 在开始菜单中找到ArcMap并单击打开，启动ArcMap，ArcMap启动界面如图1所示。图1ArcMap启动界面说明：打开ArcMap时，会弹出【ArcMap 启动】对话框。该对话框提供了几种启动ArcMap对话的选项。可以在左边目录中，打开一张最近打开过的地图文件。

3.2 打开地图文档（1）点击主菜单中的【文件】→【打开】，启动【打开】对话框，在对话框中选择到需要打开的Mxd 地图文档，如图2所示。图2 选择地图文档说明：地图文档（.Mxd）一种ArcMap存储地图的形式，可以被用户显示、修改或者与其他用户共享。但地图文档（.Mxd）并不存储实际的数据，而是存储实际数据在硬盘上的指针和有关地图显示的信息。地图文件一般还存储了地图的其他信息，如地图的大小、所包含的地图元素（标题、比例尺等）。同时还需要注意的是，不同版本的Mxd文件是不同的，高版本可以兼容之前的版本，但是低版本却无法打开高版本的Mxd文件。（2）点击【打开】，将选择的地图文档加载到ArcMap中，地图文档加载结果如图3所示，左侧为内容表，列出了可用来显示的地理图层；右侧为地图显示区。

新概念英语青少版startera知识点总结

动物：cat 猫 dog 狗 fish 鱼insect昆虫 monkey 猴子 panda 熊猫 zebra 斑马 pig 猪frog 青蛙 mouse 老鼠 parrot 鹦鹉 rabbit 兔子 tortoise 乌龟食物：apple 苹果 egg鸡蛋hamburger 汉堡包 salad 沙拉 sausage香肠tomato西红柿 pizza比萨jelly果冻颜色： green绿色 red 红色 blue 蓝色yellow黄色 orange 橙色身体部位： leg 腿 mouth 嘴 nose 鼻子玩具：Ball 球 kite 风筝 violin 小提琴xylophone 木琴doll 木偶 robot 机器人车：bike 自行车 car 小汽车train 火车 van 货车；面包车家人亲戚：family 家人 mum 妈妈 dad 爸爸 sister 妹妹 brother 弟弟friend 朋友文具：book 书 pen 钢笔 pencil铅笔 pencil case 笔袋 rubber 橡皮 ruler 尺子 school bag书包职业：dancer 跳舞者，舞蹈专家 doctor医生 nurse 护士 policeman男警察policewoman 女警察 postman 邮递员 teacher 老师数字：one two three four five six seven eight nine ten 形容个人体态：tall 高的short 矮的big大的 little 小的fat 胖的thin瘦的衣物： anorak 带帽子的夹克衫 cap 鸭舌帽 T-shirt T恤Shirt 衬衣sweater毛衣hat有檐帽方位介词：behind 在…后面 in 在…里面 in front of 在…前面 on 在…上面under 在…下面其他词汇： girl女孩 boy 男孩 sun 太阳 table 饭桌 umbrella 雨伞 king 国王 queen王后zoo 动物园 window 窗户 bone 骨头句子： at my yellow leg! 看我黄色的腿！ is my brother and sister. 这是我的哥哥和姐姐。（用于介绍某人） ’s a robot. 这是一个机器人。 it an apple？ Yes，it is./No，it isn’t.它是一个苹果吗？是的，它是。/不，它不是。 isn’t my schoolbag. 这不是我的书包。 this a schoolbag? Yes,it is. /No,it isn't. 这是一个书包吗？是的，它是。/不，它不是。 ’s this？It’s a hamburger. 这是什么？这是一个汉堡。 What’s that？It’s a salad. 那是什么？那是一盘沙拉。 What is it？It’s an egg. 它是什么？它是一个鸡蛋。 8.How old are you？I’m eleven. 你多大了？我十一岁了。 9.Are you seven？Yes，I am. /No，I’m not.你七岁了吗？是的，我是。/不，我不是。 10.You aren’t five. 你不是五岁。 11.He’s tall.他很高。She isn’t fat. 她不胖。 12.Is she tall？Yes,she is./No，she isn’t.她高吗？是的，她高。/不，她

arcgis基础工具教程

1/数据的导入（添加）（1）点击添加数据（2）点击小三角，找到你所需添加文件所在文件夹位置（3）选中你所要添加的文件，添加，即可在内容列表看到你所添加进来的文件

2、数据的导出右键需要导出图层，点击【数据】-【导出数据】，导出到所要放的文件夹，命名文件。点击保存即可，导出的图层会自动加载到左边内容列表

3.属性的标注右键你所需图层，点击【属性】，切换到标注，点击标注此图层中的要素，标注字段选择你所需标注的字段，如地类名称，地类编码，行政村等 3、属性选择。例如选择河流名称为港边水的河流，右键图层，，点击【打开属性表】，点击【按属性选择】，双击河流名称，河流名称会出现在下面输入框里，点击【=】，点击【获取唯一值】，双击港边水，下面输入框里即就出现河流名称=港边水的字样，代表属性选中，点击应用，即选中

4、数据合并数据合并需注意，要合并的数据必须同为面或者同为线，同为点，面和线，面和点，线和点都是不可以合并的，两个以上数据都可以合并，可以是两个、三个、四个，多个，点击【地理处理】-【合并】，输入所需合并的数据，此处合并11年和13年的数据，输出数据，选择你所需放的文件夹位置，命名输出的文件，点击确定，输出后的文件会自动加载到内容列表

5、数据筛选，打开属性表，按ctrl+f,即可打开查找，输入查找内容，文本匹配可选择任何部分，也可选择整个字段，可以选择仅搜索所选字段 6、字段添加。打开属性表，点击左上角按钮，点击【添加字段】，输入字段名称，选择类型，常用为文本型和双精度型，文本型要定义字段长度，双精度要定义精度和小数位数

VB+ArcGis Engine 开发零基础GIS程序框架教程

VB+ArcGis Engine开发零基础GIS程序框架教程第一步配置环境和设计界面环境：ArcGisEngine 9.1 + Microsoft Visual Basic 6.0 使用Engine控件：ESRI ToolbarControl, ESRITOCControl 、ESRILicenseControl、ESRIMapControl。（按Ctrl+T调出部件面板，选中以下控件）再从[工程]-[引用]添加一下引用：

界面布局（右侧大的MapcControl命名为MapControl1，为显示地图主界面。左下角的MapcControl命名为MapControl2，作为地图鹰眼。在工具栏里添加如图的几个按钮即可。其它再添加一个CommonDialog1和状态栏）：

在ESRI ToccControl和 ESRIToolbarControl属性里绑定控件EsriMapControl （buddy选择MapControl1）。这样基本界面就布置好了。第二步加载地图代码为： '打开地图文档 On Error Resume Next Dim sFileName As String With CommonDialog1 .DialogTitle = "Open Map Document" .Filter = "Map Documents (*.mxd;*.pmf)|*.mxd;*.pmf" .ShowOpen If .FileName = "" Then Exit Sub sFileName = .FileName End With If MapControl1.CheckMxFile(sFileName) Then MapControl1.LoadMxFile sFileName

ArcGIS教程：路径分析

ArcGIS教程：路径分析求解路径分析表示根据要求解的阻抗查找最快、最短甚至是最优的路径。如果阻抗是时间，则最佳路线即为最快路线。如果阻抗是具有实时或历史流量的时间属性，则最佳路径是对指定日期和时间来说最快的路径。因此，可将最佳路径定义为阻抗最低或成本最低的路径，其中，阻抗由您来选择。确定最佳路径时，所有成本属性均可用作阻抗。可在路径分析中累积任意多个阻抗属性，但累积属性不会对沿网络计算路径造成任何影响。例如，如果选择时间成本属性作为阻抗属性，并且希望累积距离成本属性，最终仅会使用时间成本属性来优化解。求解过程中将累积并报告总距离，但此例中的路径并不是根据距离计算得出的。查找通过一系列停靠点的最佳路径将遵照与执行其他网络分析相同的工作流。一、路径分析图层路径分析图层将存储路径分析的所有输入、参数和结果。 1、创建路径分析图层要通过 Network Analyst 工具条创建路径分析图层，可以单击 Network Analyst > 新建路径。

创建新的路径分析图层后，该图层即会与它的五个网络分析类(停靠点、路径、点障碍、线障碍和面障碍)一起显示在Network Analyst 窗口中。路径分析图层也会以名为“路径”的复合图层显示在内容列表中(如果地图文档中已经存在名称相同的路径，则会以路径 1、路径 2 等显示)。存在五种要素图层 - 停靠点、路径、点障碍、线障碍和面障碍。其中的每个要素图层都有默认的符号系统，您可在图层属性对话框中对这些默认的符号系统进行修改。二、路径分析类路径分析图层由五种网络分析类组成。下面各部分概述了每个类及其属性。 1、停靠点类该网络分析类用于存储路径分析中用作停靠点的网络位置。“停靠点”图层包含四种默认符号：已定位停靠点、未定位停靠点、有错误的停靠点和有时间冲突的停靠点。您可以在图层属性对话框中修改“停靠点”图层的符号系统，此对话框中包含停靠点的自定义符号系统类别，它位于 Network Analyst > 序列化的点中。创建新的路径分析图层后，“停靠点”类为空。仅当将网络位置添加到该类后，它才不为空。创建路径至少需要两个停靠点。 2、停靠点属性一些停靠点属性仅在定义起始时间或启用时间窗后才可用，其中，起始时间和时间窗均是路径分析图层的图层属性对话框的分析设置选项卡中的参数。 3、路径类路径类存储通过分析生成的路径。与其他要素图层相同，它的符号系统也可通过图层属性对话框进行访问和更改。

新概念英语青少版入门级AStarterA重点知识总结

Unit 6 This is my family. 词汇：family mum dad sister brother friend 句型：This is... 句子：1.This is my mum. Lesson 2 词汇：my your 缩写：What's=What is my name's=my name is 句子：①What's your name？ My name's Pop. Unit 7 Happy birthday? 词汇：bike car doll robot train van 缩写：it's it's=it is it isn't it isn't=it is not 词汇：a an 句子：①It's a van. ②It isn't a car. 短语：a train/van/robot/car An apple/insect/egg/umbrella Lesson 2 句型：Is it...? 句子：㈠Is it an apple？ Yes，it is./No,it isn't.

Unit 8 That's my book. 词汇：book, pen, pencil ,pencil case, rubber, ruler, school bag 缩写：this is this isn't this isn't= this is not that is that isn't that isn't= that is not 句子：①肯——This is my book. 否——This isn't my book. ②肯——That's my book. 否——That's isn't my book. Lesson 2 句型：Is this...? Is that...? 句子：①Is this a pencil？ Yes，it is./No,it isn't. ②Is that a school bag? Yes，it is./No,it isn't. Unit 9 What's this,Mum? 词汇:bone, hamburger, salad, sausage, tomato, pizza 缩写：What's=What is 句型：What's...? 句子：What's this？It's a hamburger. What's that? It's a bone. Lesson 2

新概念英语青少版STARTERA测试题

NAME_______ SCORE________ 少儿新概念英语STARTER A 阶段测试【UNIT1--UNIT5】 A.口试部分（满分10分） SCORE________ CONTENTS__________________ B.笔试部分（满分90分） SCORE________ 1、请按正确的格式和正确的顺序书写A —Z 这26个字母的大小写。（1×26=26） 2、将下列单词分类。(1×10=10) 3、写出【I 】、【J 】【R 】【U 】【X 】【Y 】对应的字母词。（1×6=6） 4、根据图片写出对应单词。（1×5=5）【】【】【】【】【】 5、根据上下文意思，补全对话。（1×7=7） (1) Robert :_______,Flora! Flora: Hello, Robert! Robert:Hi, Kim! (2) Robert: Oh!An insect! ! Flora:Help! (3) Peg ：！An orange! Pop: Look _______ Peg! Max: _____ !Peg!

Flora: ,Dan! dog! 6、英译汉。（1×4+2×2=8） (1)Oops! __________________________________________________________________________________________ (2)Hurray! __________________________________________________________________________________________ (3)Happy birthday! __________________________________________________________________________________________ (4)Bad dog! __________________________________________________________________________________________ (5)Please! Stop my dog! __________________________________________________________________________________________ (6)Look! The zoo! __________________________________________________________________________________________ 7、圈出图片对应英文的正确书写，并连线。（2×4=8） 8、汉译英。（2×10=20） (1)哇哦！一个橙蓝相间的风筝！ ______________________________________________________________________________________________ (2)果冻！可口的！ ______________________________________________________________________________________________ (3)没有猫，没有鱼！ _____________________________________________________________________________________________ (4)一把黄绿相间的伞！ ______________________________________________________________________________________________ (5)谢谢你，妈妈！ ______________________________________________________________________________________________ (6)看你的红鼻子！ _________________________________________________________________________________________________ (7)帮忙呀！帮忙呀！ _________________________________________________________________________________________________ (8)你好，Dan！好狗！ _________________________________________________________________________________________________ (9)我的帽子！我的风筝！ _________________________________________________________________________________________________

arcgis10.0__中文教程_

练习10 –ArcView GIS 3.3 网络分析：网络分析是GIS空间分析的重要组成部分，它的主要内容包括： ●寻找最佳行进路线，如：找出两地通达的最佳路径。 ●确定最近的公共设施，如：引导最近的救护车到事故地点。 ●创建服务区域，如：确定公共设施（医院）的服务区域。通过对本实习的学习，应达到以下几个目的： ●加深对网络分析基本原理、方法的认识； ●熟练掌握ARCVIEW网络分析的技术方法。 ●结合实际、掌握利用网络分析方法解决地学空间分析问题的能力。 1．寻找最佳路径 (2) 2. 确定最近设施 (6) 3. 创建服务区域 (7) 软件准备：Arcview GIS 数据准备：街道图层：s_fran 医院图层：hospital.shp 事件位置：del_loc.shp 加载Arcview网络分析模块：执行菜单命令：[Files]>>[Extension] 命令，在Extensions对话框中选中Network Analyst，单击OK，即装入Network Analyst空间分析扩展模块。注：通过菜单命令[Network]>>[Show Problem Definition…] 可以查看当前网络分析问题的定义。运行ArcV iew GIS

11．寻找最佳路径为邮递员设计最佳投递路线，该路线应是投递时的最短路线，并选择最有效率的投递顺序。具体的操作如下： (1)运行[开始]>>[程序]>>[ESRI]>>[ArcView GIS 3.3]>>[ArcV iew GIS3 .3] 在出现的对话框中选择[with a new View] 新建一个视图 (2)在视图界面下点击添加图层按钮(如下图中红色前头所示)可以从硬盘上添加 Shape文件添加城市街道的网络线层面S_fran和投递点层面Del_loc。（见下图）。

新概念英语青少版starteraunit9课件

Unit 9: What’s this, Mum 妈妈，这是什么句型：妈妈，这是什么What’s this, Mum 那是什么What’s th at 它是一根骨头、It is a It’s a bone。常用表达:让我们玩游戏！Let’s play! 轮到你了！Your turn! 词汇：bone骨头, hamburger汉堡, salad色拉, sausage香肠, tomato番茄, pizza比萨饼语音: 字母o在单词中的发音。如：fox, box, not, mop, hot, hop, dog, frog, shop, orange, O音拼读说唱练习： 1 Hop. Hop. Hop. 跳。跳。跳。Oh, it’s hot. 哦，热起来了。 No, it’s not. 不，不热。Hop. Hop. Hop. 跳。跳。跳。 2 Is that a fox on a box 那只狐狸在一只盒子上面吗No, it’s not. 不，它不在。 It ’s a mop on a box. 它是一把拖把在盒子上面。语法: 特殊疑问句特殊疑问句是以特殊疑问词开头，对句中某一成分提问的句子。常用的疑问词有:what 、who 、whose 、which 、when 、where 、how 、why等。回答特殊疑问句时，不能用yes / no，即问什么答什么，尤其是简略回答。扩展训练：what 疑问句 What is this ---What’s this/that 这是/那是什么 That’s a salad. 那是色拉。What is it 它是什么 It’s a bone,/hamburger,/salad,/sausage, tomato,/pizza What’s your name--- What is your name My name is Steven.

新概念英语青少版STARTERA测试题

NAME_______ SCORE________ 少儿新概念英语STARTER A阶段测试【UNIT1--UNIT5】 A.口试部分（满分10分） SCORE________ CONTENTS__________________ B.笔试部分（满分90分） SCORE________ 1、请按正确的格式和正确的顺序书写A—Z这26个字母的大小写。（1×26=26） 2、将下列单词分类。(1×10=10) 3、写出【I】、【J】【R】【U】【X】【Y】对应的字母词。（1×6=6） 4、根据图片写出对应单词。（1×5=5）【】【】【】【】【】 5、根据上下文意思，补全对话。（1×7=7） (1) Robert :_______,Flora! Flora: Hello, Robert! Robert:Hi, Kim! (2)Robert: Oh!An insect! ! Flora:Help! (3) Peg：！An orange! Pop: Look _______ Peg! Max: _____ !Peg!

ArcGIS基本操作教程

Arcgis基本操作教程（所有资料来自网络）

目录 1.配准栅格地图 (1) 1.1跟据图上已知点来配准地图 (1) 1.1.1选择标志性程度高的配准控制点 (1) 1.1.2从基础数据底图上获取控制点坐标 (1) 1.1.3增加Georeferncing 工具条 (2) 1.1.4加载需要配准的地图 (3) 1.1.5不选择Auto Adjust (3) 1.1.6在要配准的地图上增加控制点 (4) 1.1.7重复增加多个控制点检查残差 (5) 1.1.8更新地图显示 (5) 1.1.9保存配准图像 (6) 1.1.10增加有坐标的底图检验配准效果 (7) 1.2根据GPS观测点数据配准影像并矢量化的步骤 (9) 2.图形的失量化录入 (11) 2.1半自动失量化 (11) 2.1.1启动ArcMap (12) 2.1.2栅格图层的二值化 (12) 2.1.3更改Symbology设置 (13)

2.1.4定位到跟踪区域 (14) 2.1.5开始编辑 (14) 2.1.6设置栅格捕捉选项 (15) 2.1.7通过跟踪栅格像元来生成线要素 (16) 2.1.8通过跟踪栅格像元生成多边形要素 (18) 2.1.9改变编辑目标图层 (18) 2.1.10结束你的编辑过程 (20) 2.2批量矢量化 (20) 2.2.1启动ArcMap，开始编辑 (20) 2.2.2更改栅格图层符号 (21) 2.2.3定位到实验的清理区域 (22) 2.2.4开始编辑 (23) 2.2.5为矢量化清理栅格图 (23) 2.2.6使用像元选择工具来帮助清理栅格 (24) 2.2.7使用矢量化设置 (27) 2.2.8预览矢量化结果 (28) 2.2.9生成要素 (29) 2.2.10结束编辑过程 (31) 2.3手工数字化 (31) 2.3.1在ArcCatalog下新建一个空的shapefile： (31)

新概念英语青少版startera知识点总结(全)

单词：动物：cat 猫 dog 狗 fish 鱼insect昆虫 monkey 猴子 panda 熊猫 zebra 斑马 pig 猪frog 青蛙 mouse 老鼠 parrot 鹦鹉 rabbit 兔子 tortoise 乌龟食物：apple 苹果 egg鸡蛋hamburger 汉堡包 salad 沙拉 sausage香肠tomato西红柿 pizza比萨jelly果冻颜色： green绿色 red 红色 blue 蓝色yellow黄色 orange 橙色身体部位： leg 腿 mouth 嘴 nose 鼻子玩具：Ball 球 kite 风筝 violin 小提琴xylophone 木琴doll 木偶 robot 机器人车：bike 自行车 car 小汽车train 火车 van 货车；面包车家人亲戚：family 家人 mum 妈妈 dad 爸爸 sister 妹妹 brother 弟弟friend 朋友文具：book 书 pen 钢笔 pencil铅笔 pencil case 笔袋 rubber 橡皮 ruler 尺子 school bag书包职业：dancer 跳舞者，舞蹈专家 doctor医生 nurse 护士 policeman男警察policewoman 女警察 postman 邮递员 teacher 老师数字：one two three four five six seven eight nine ten 形容个人体态：tall 高的short 矮的big大的 little 小的fat 胖的thin瘦的衣物： anorak 带帽子的夹克衫 cap 鸭舌帽 T-shirt T恤Shirt 衬衣sweater毛衣hat有檐帽方位介词：behind 在…后面 in 在…里面 in front of 在…前面 on 在…上面under 在…下面其他词汇： girl女孩 boy 男孩 sun 太阳 table 饭桌 umbrella 雨伞 king 国王 queen王后zoo 动物园 window 窗户 bone 骨头句子：

ArcGIS中文基础教程

第一章GIS 的概念和需求理解GIS的三种角度： GIS是一个用于管理、分析和显示地理信息的系统。地理信息可以通过一系列地理数据集来表达。而地理数据集则通过使用简单的，普通数据结构来为地理信息建模。GIS包含了一套用以处理地理数据的综合工具。我们可以从多个角度来理解地理信息系统是如何工作于地理信息的： 1．从空间数据库的角度看：GIS是一个包含了用于表达通用GIS数据模型（要素、栅格、拓扑、网络等等）的数据集的空间数据库。 2．从空间可视化的角度看：GIS是一套智能地图，同时也是用于显示地表上的要素和要素间关系的视图。底层的地理信息可以用各种地图的方式进行表达，而这些表现方式可以被构建成“数据库的窗口”，来支持查询、分析和信息编辑。 3．从空间处理的角度看：GIS是一套用来从现有的数据集获取新数据集的信息转换工具。这些空间处理功能从已有数据集提取信息，然后进行分析，最终将结果导入到数据集中。这三种观点在ESRI ArcGIS中分别用ArcCatalog（GIS是一套地理数据集的观点）、ArcMap（GIS是一幅智能的地图）和ArcToolbox（GIS是一套空间处理工具）来表达。这三部分是组成一个完整GIS的关键内容，并被用于所有GIS 应用中的各个层面。从空间数据库的角度： GIS是世界上独一无二的一种数据库――空间数据库（Geodatabase）。它是一个“用于地理的信息系统”。从根本上说，GIS是基于一种使用地理术语来描述世界的结构化数据库这里我们来回顾一些在空间数据库中重要的基本原理。地理表现形式作为GIS空间数据库设计工作的一部分，用户要指定要素该如何合理的表现。例如，地块通常用多边形来表达，街道在地图中是中心线（centerline）的形式，水井表现为点等等。这些要素会组成要素类，每个要素类都有共同的地理表现形式。每个GIS数据集都提供了对世界某一方面的空间表达，包括：基于矢量的要素（点、线和多边形）的有序集合