6+ Aplikasi Penghasil Uang Tanpa Modal yang Paling Populer

Di era digital yang semakin maju seperti sekarang ini, cara menghasilkan uang juga semakin maju dan lebih mudah. Bahkan, hanya dengan menggunakan smartphone yang Anda miliki, Anda sudah bisa menghasilkan uang. Bermodalkan aplikasi penghasil uang yang diinstal di smartphone, menghasilkan uang dapat dilakukan dimana saja. Hebatnya lagi, semua itu bisa dilakukan tanpa modal sepeser pun. Keren, kan?

Aplikasi Penghasil Uang

Ada banyak aplikasi penghasil uang tanpa modal yang dapat diinstal di smartphone secara gratis. Melalui aplikasi tersebut, Anda dapat menjalankan misi, membaca artikel, menonton video dan hal lainnya. Selanjutnya, setelah Anda selesai melakukannya semua, Anda akan mendapatkan bayaran yang nantinya langsung masuk ke rekening Anda. Nah, berikut ini ada beberapa aplikasi yang dapat menghasilkan uang secara online, gratis dan tanpa modal. Apa saja itu?

1. Baca Plus

Salah satu aplikasi yang dapat menghasilkan uang adalah aplikasi Baca Plus. Aplikasi ini dapat Anda download secara gratis di Google PlayStore. Baca Plus merupakan aplikasi yang berisikan artikel berita dan video. Melalui aplikasi ini Anda dapat membaca berbagai macam berita dan video terbaru. Hebatnya, saat Anda telah menyelesaikan membaca berita atau menonton video, Anda akan mendapatkan poin yang dapat Anda klaim untuk ditukarkan pulsa atau uang tunai.

2. AppNana

Bagi Anda yang hobi bermain game tapi juga ingin menghasilkan uang, AppNana adalah aplikasi yang cocok untuk Anda. Dengan bermain game di AppNana, Anda akan memperoleh poin. Minimal poin yang dapat ditukarkan yaitu 45.000 poin dan dapat Anda tukarkan dengan uang sejumlah 2 dollar di Paypal. Tidak hanya bermain game, dengan mendownload aplikasi sesuai arahan di AppNana, Anda juga bisa menghasilkan uang. Intinya, semakin banyak hal yang Anda lakukan di AppNana, maka uang Anda hasilkan juga akan banyak.

3. Cash for Apps

Sesuai namanya, aplikasi penghasil uang yang satu ini akan membayar Anda untuk setiap aplikasi yang Anda install di smartphone. Setelah menginstall aplikasi sesuai perintah Cash for App, Anda akan mendapatkan reward berupa poin yang nantinya dapat ditukar dengan uang.

Bagi Anda yang ingin menukar poin, tunggu poin mencapai 300 poin kemudian tukar dengan 1 dollar. Jika Anda ingin menukar poin dengan hadiah menarik dari dari Google Play, tunggu poin mencapai 3000 dulu ya.

4. WhatsAround

Bagi Anda yang suka jalan-jalan ke banyak tempat sambil menghasilkan uang, aplikasi yang satu ini cocok sekali untuk Anda. Dengan WhatsAround, Anda dapat mengunggah foto-foto travelling ke berbagai tempat. Setelah itu, Anda akan mendapatkan poin yang dapat Anda jadikan saldo Amazon, PayPal, Google Play dan masih banyak lagi.

5. TikTok

TikTok menjadi aplikasi hiburan yang sangat populer akhir-akhir ini. Dengan musik dan gerakan menarik, Anda dapat mencari hiburan di sini. Ternyata aplikasi ini juga menawarkan penghasilan bagi Anda lho. Anda bisa memilih menghasilkan uang sebagai penonton atau kreator. Sebagai penonton, Anda hanya cukup menonton video-video yang ada di TikTok. Sebagai kreator, Anda dapat menghasilkan pendapatan lewat endorse atau For Your Page (FYP) rutin di TikTok.

6. Whaff Rewards

Aplikasi penghasil uang tanpa modal selanjutnya adalah Whaff Rewards. Bagi kamu yang mau bermain game sambil dapat uang, segera saja install aplikasi ini di smartphone Anda. Dengan bermain game dan menyelesaikan misi, Anda akan mendapatkan poin yang dapat ditukar dengan uang. Lumayan, kan?

7. Snack Video

Aplikasi penghasil uang tanpa modal lainnya adalah Snack Video. Aplikasi ini hampir sama dengan TikTok. Perbedaan dasarnya, Snack Video lebih berfokus ke video-video pendek lucu. Jika kamu menonton video di aplikasi tersebut, Anda akan mendapatkan poin yang dapat Anda tukarkan dengan uang lho. Menarik sekali ya bisa menonton video lucu sambil menghasilkan uang.

Demikian artikel mengenai aplikasi penghasil uang tanpa modal yang bisa Anda coba. Semoga dapat bermanfaat untuk menambah pundi-pundi pemasukan Anda. Jangan lupa untuk segera install salah satu aplikasinya agar uang Anda bertambah sesegera mungkin.

8 Tips Jadi Youtuber Sampai Bisa Kaya Raya

Menjadi Youtuber adalah salah satu pekerjaan yang sedang digandrungi oleh anak muda zaman sekarang. Hal ini tidak terlepas dari populernya penggunaan platform Youtube sebagai sosial media untuk berbagi ilmu, informasi atau sekedar sharing tentang pengalaman kehidupan sehari-hari.

Namun tentunya tujuan banyak orang untuk menjadi Youtuber adalah karena uang. Ya, memang mendapatkan uang melalui Youtube bukan hal yang asing lagi. Bahkan mulai dari orang biasa hingga artis pun banyak yang menggeluti dunia Youtube. Dan penghasilan mereka juga tidak main-main, puluhan hingga ratusan juta setiap bulannya.

Tips Menjadi Youtuber

Akan tetapi, untuk menjadi Youtuber sampai bisa kaya raya tidak mudah begitu saja. Ada banyak tips yang perlu dipelajari, terutama bagi para pemula. Berikut ini ada 8 tips jadi Youtuber sampai bisa kaya raya.

1. Menentukan Konten

Hal utama yang perlu dilakukan agar menjadi Youtuber sukses adalah dengan menentukan konten. Sebab konten adalah raja, jadi usahakan untuk membuat konten yang berkualitas dan banyak diminati oleh penonton. Seperti contohnya konten yang sedang diminati saat ini, yaitu tentang cara mengatur keuangan.

Selain itu, jangan plagiasi konten orang lain. Boleh mencontoh namun harus dengan gaya sendiri. Sehingga konten yang kita buat seakan-akan berbeda dengan orang lain, padahal tujuan informasinya sama. Perlu diketahui, dengan memiliki konten yang berkualitas tentu iklan AdSense yang muncul nantinya juga akan memiliki harga yang tinggi.

2. Upload Konten di Waktu yang Tepat

Waktu upload video konten di Youtube tidak boleh sembarangan. Usahakan untuk mengunggah video Anda di waktu pukul 07.00 – 10.00 malam. Sebab di waktu itulah banyak orang sedang beristirahat santai dan biasanya membuka internet untuk mencari informasi.

Cara yang tepat untuk melihat waktu yang baik saat memposting video Anda adalah dengan mengamati grafik jumlah penonton di video-video Anda sebelumnya. Disana Anda dapat melihat pada hari apa dan jam berapa Subscriber Anda menonton video Anda.

3. Membuat Konten Secara Teratur

Jika sudah memiliki penonton dan Subscriber, tips selanjutnya yang perlu Anda lakukan agar channel Youtube Anda berkembang adalah dengan membuat konten secara teratur. Misalnya saja sekali dalam seminggu atau dua kali dalam seminggu. Sebab, pengikut channel Youtube Anda akan menanti-menanti video terbaru Anda.

Tidak akan hanya menambah kuantitas konten Anda, membuat konten secara teratur juga akan meningkatkan exposure di Youtube. Artinya, secara perlahan-lahan akan meningkatkan jumlah penonton video Anda. Oleh karena itu saat Anda mengunggah satu video, maka Anda wajib untuk memikirkan ide konten video selanjutnya. Jadi, tidak ada kata malas-malasan jika ingin kaya raya dengan menjadi Youtuber.

4. Melibatkan Orang lain

Ada kalanya timbul rasa bosan jika membuat video hanya tentang diri sendiri. Bahkan bukan hanya untuk seorang Creator saja, namun juga pada penonton. Oleh karena itu Anda perlu melibatkan orang lain kedalam konten Anda. Entah itu keluarga, teman atau pasangan.

Anda bisa membuat konten tentang vlog bersama keluarga, main games bersama teman dan lain-lainnya. Ajaklah orang yang nyaman saat tampil di depan kamera, agar nanti hasil dari videonya juga bagus. Setelah itu Anda tinggal memasuki proses editing untuk memotong bagian video yang tidak diperlukan.

5. Tampilkan Kolom Komentar

Ada Youtuber yang tidak suka menerima komentar dari penonton. Sehingga mereka menyembunyikan kolom komentar di setiap postingan video mereka. Nah, hal itu bukan termasuk cara yang benar apabila Anda ingin menjadi Youtuber yang sukses dan banyak pengikutnya.

Dengan menerima komentar dari penonton, maka hal tersebut akan dapat memperbaiki konten kita. Dimana letak kekurangannya, apa yang tidak disukai dari penonton dan hal-hal lainnya. Ibarat pepatah, buang buruknya dan ambil baiknya.

6. Membalas Komentar Penonton

Membalas komentar penonton adalah satu cara meningkatkan engagement video Anda. Anda dapat merespon setiap pertanyaan atau saran dari mereka mengenai ide konten selanjutnya.

Selain itu, dengan rajin membalas komentar penonton maka secara tidak langsung akan membuat Anda dicap sebagai Youtuber yang ramah. Hal tersebut tentu dapat meningkatkan popularitas Anda dan banyak disenangi oleh orang lain.

7. Share ke Media Sosial Lain

Untuk meningkatkan jumlah viewers, Anda dapat membagikan video hasil unggahan Anda ke media sosial yang Anda miliki, seperti di Facebook, WhatsApp, Instagram dan lain-lain.

Jangan lupa juga untuk mengajak pengikut media sosial Anda untuk like, comment dan subscribe di channel Youtube Anda.

8. Siapkan dan Gunakan Alat yang Mumpuni

Jika Anda ingin menghasilkan video yang berkualitas tentu Anda harus menyiapkan peralatan yang mumpuni. Seperti kamera, audio, lighting hingga background yang mendukung. Namun jika Anda belum dapat menyiapkan semuanya, Anda dapat mencicilnya dari uang hasil Youtube Anda. Yang terpenting niat dan komitmen Anda harus jelas serta tidak gampang menyerah.

Demikian artikel mengenai 8 tips menjadi Youtuber sampai bisa kaya raya. Semoga dapat bermanfaat dan membantu Anda yang saat ini sedang ingin untuk menggeluti dunia Youtube.

5 Advantages of the Indonesian Bus Simulator Game (BUSSID) Maleo

There are lots of fun and interesting bus simulator genre games to play on android smartphone devices. One of them is the Indonesian Bus Simulator game (Bus Simulator ID) or better known as BUSSID. This game is made by the original Indonesian developer, Maleo and was released in 2017. Until now, the BUSSID game continues to be updated along with the addition of various features and also to fix existing bugs.

The Bus Simulator Indonesia game is one of the most popular games to play. Maybe this is because the BUSSID game has advantages that other bus simulator games don’t have, especially those that can be played on Android smartphones. So, what are the advantages of the BUSSID game?

  1. Detailed Graphics

For Gamers, graphics are the most important thing in a game. Because with good graphics, it will certainly make players more comfortable playing the game, including games with the simulation genre such as the BUSSID game.

Well, that’s one of the advantages of the BUSSID game. Where the Maleo team as the game developer has completed detailed graphics in the BUSSID game. Yes, even though it doesn’t seem very realistic, it is of sufficient quality and not boring.

  1. Environment, Cities, and Authentic Indonesian Buses

As the name implies, the BUSSID game deliberately presents a bus simulation game with a distinctive Indonesian nuance. Starting from the village environment, urban areas, to the various types of original buses that are usually milling about on the streets of Indonesia.

When playing the BUSSID game, you will be able to enjoy the beautiful village roads with rice fields on the right and left, the sensation of driving at high speed on toll roads, and also passing the longest bridge in Indonesia, the Suramadu bridge.

  1. Design Your Own Livery Bus

Livery or sometimes also called skin is clothing or uniform that is used to symbolize the identity of a bus company (PO).

In the BUSSID game, you can design and use your own livery and replace it without limits. Not even just livery, but you can also add various cool accessories on the bus that you will use to play, such as wheel accessories, strobe lights, bumpers, and others.

  1. There is a Vehicle MOD System

There are many who say that the Bus Simulator Indonesia game is the android version of ETS2. Yes, it’s not wrong, because there are many interesting features provided in the BUSSID game. One of these interesting features is the vehicle MOD system.

Through the vehicle MOD system feature (vehicle MOD) players can install and use various types of vehicles other than buses available on the BUSSID game dashboard. Vehicles such as trucks, pick up cars, motorcycles, and others can be used freely in the BUSSID game. Cool, right?

  1. Always Updated

The purpose of developers updating an application (including games) is to update or add the latest features and also fix problems (bugs) in the application.

This is also what the Maleo team as the BUSSID game developer does, who continues to consistently update the BUSSID game so that it is better than the first time the game was released. When this article was published, the BUSSID game has been updated to version 3.6.1.

Those are some reviews about 5 advantages of the Bus Simulator ID (BUSSID) game. Of the five advantages of the BUSSID game above, of course there are many other advantages that we cannot mention one by one. Therefore, for those of you who want to try this Android version of the bus simulation game, let’s just download it on the Play Store.

 

Best Online Games for Grown Ups

Online games for grown ups are often sought because it provides entertainment while still being challenging enough for adults. Mostly, adults will choose role-playing games because it requires a deeper understanding to actually permeate the game.

So, we have several RPG that adults will surely enjoy so much. RPG is indeed successful in making you feel addicted. Moreover, these games are very much recommended to play during leisure time.

RPG or Role Playing Game is one of the very popular game genres. An exciting RPG game can forget our thoughts for a moment from the tiring work. And the many elements provided by the genre make us feel attached to the world in the game. RPG games are closely related to the story and role-playing style, which means you will follow the story of someone or a group in the game world.

Even when playing, you will feel a sensation that is not much different when you watch exciting action movies. Especially if you are immersed in the story! Now widely available in android and iOS, online games for grown ups have advantages in terms of portability, so you can play anywhere and anytime.

Recommended MMORPG Games

For old school players in the 2000s, you must be very familiar with this one MMORPG game! Yes, especially if it is not Ragnarok M: Eternal Love, which now comes in a mobile version with an open world concept. Exactly the same as in the original game which was released in 2002. At the beginning of the game, you will be asked to choose six different classes.

There is also you are required to increase the level of character Ragnarok M: Eternal Love by getting EXP from hunting monsters or doing quests. The second one to be mentioned is Laplace M, which follows in the footsteps of other successful mobile RPG such as Ragnarok M: Eternal Love or Lineage 2 Revolution which was released earlier.

For your information, the best online games for grown ups developed by ZlongGames has even succeeded in occupying the top of the best-selling game version of Google Play for Android. Moreover, the Laplace M game is also relatively easy to be played by new players, so you are welcomed to try!

More RPG Choices

If the two previous MMORPG games offer cute graphics, it is different from Lineage2 Revolution which provides realistic 3D graphics. The best RPG game made by the big game company from South Korea, Netmarble Games allows you to meet millions of other players in real-time.

One important key in playing Lineage2 Revolution is character leveling, where the higher the character, the easier and more items can be opened. Who doesn’t know this one online RPG game? Especially if it’s not GrandChase. The remake of the game, which was first released in 2003, was immediately sought after by gamers because it now offers fully 3D graphics.

You can choose from more than 70 heroes that can be played with various fighting styles. Of course, you can also meet and play with your friends online. No wonder GrandChase is called the best MMORPG game on Android. Those are the best online games for grown ups that you can play right away!

In this article, we are focusing on recommending the available RPG games that you can try. RPG is an abbreviation of Role Playing Game. The concept of the game is to portray the character of a character and live the chosen story. This game is not only played by one character but with several characters with different characters.

You will work together to form a story in one episode of the game. Not only presents an exciting game, but RPG games also have interesting storylines in each fragment of the episode. You must have good collaboration with the characters in the team. If you make great teamwork, the gameplay results of online games for grown ups will be satisfying.

These Brain Games Online Will Make You Smarter

Brain games online are now much sought after by gamers. When you are bored with office work, try to play brain teasers as these types of games can not only make the mood better but also can help improve brain sharpness and memory.

The brain teasers are highly associated with math; therefore, you are able to train your brain without even realizing it. Turning boring problems into gamification is a great way to learn, and here are some interesting game options for you to try.

The first game is Math Duet, which is a brain teaser game that has the same appearance as a card or chess game. The difference is that this game requires math problems instead, which you need to finish in order to win the duel. Basically, the brain games online are all about math problems that are turned into a game, which makes it fun and challenging.

Brain Games Online Ideas

Another option for you to try is the Quick Brain, which is a game that challenges your way of thinking by challenging you with math problems as well. The game has a fast time out, which trains your brain to develop and think critically so you can finish it faster and better. Besides being fun and quite stressful, you will also be spoiled by the appearance of the game that is pleasing to the eye.

Fight the zombies while you finish the math problems. What would happen if this fight happened? Find out about it in Math Vs Undead, where you can feel all the adventures by fighting zombies.

When the math problem appears, a blue-ish green zombie will appear in front of you. The goal is to answer the question quickly while the zombie is bothering you. Therefore, it is necessary to have the full concentration to solve the problem quickly and precisely, and that is the most important thing to fight the Undead.

Another Alternative

Another brain games online alternative is Math Workout, which has an interesting appearance in the form of bubble questions. In this question bubble, at the bottom, there is a choice of answers. To answer the question, you must match the bubble with the available answers.

And another difficult game is Brain It On! where there are 95 levels that you can play. If you play from level one, of course, the level of difficulty is still quite low. But, if you have passed level 15, the level of difficulty will increase even more! How to play this game is very easy, where you only need to draw something so that the mission given is completed.

Collect the Pens

You can also play this very easy Brain Dots game, where you just draw so the two balls hit each stage. But do not be happy just yet, because even though the way to play is easy, the level of difficulty will also be higher as you level up. In this game, you can collect many times pens and pencils, from the ordinary to the colors.

How interesting are not these brain-teasing games? So, you can play everything to fill your free time and keep training your brain at the same time! Through these brain games online, you will feel entertained as well as developing yourself at the same time!

Brain teasers don’t mean they have to be boring. It’s proven that the games mentioned above can make you not take your eyes off the screen even though you feel dizzy. Who says games always bring negative effects to the brain of the players?

Well, games can also be used to provide positive stimulation in training the brain. By using a brain teaser game application that you can play on a smartphone right now, you can improve your brain’s ability. These brain games online are useful and fun, right?

 

Reasons Why You Should Play Harvest Moon Again

Harvest Moon is readily available on your smartphone right now, but you most likely had played it years and years ago. It’s a legendary game where you can easily get addicted, so why not replay the game again?

This time, use your smartphone to play this role-playing and simulation game instead of using the PlayStation. Should you need more reasons to replay the game, or want to try it for the very first time, why don’t you read on further below?

The hallmark of this game back then was to tell the story of a knight who was having the adventure to save the world. At the time, Harvest Moon was competing with other cool games such as Final Fantasy, Legend of Dragoon, etc.

These games have a game system, a story, and also charming graphics, and this game won with the simple graphic quality. It is able to prove, the greatness of a game is not just solely based on graphics, but also the game system and the experience it offers.

This Game Has Unforgettable Characters

This game is not only about managing a farm and animal husbandry but also about the interaction between characters, as well as various interesting moments that become replay value or the feasibility of this game to be played repeatedly.

The cute character design is undeniably the selling point of this game and is still widely remembered until now. The characteristics of Harvest Moon character is a mini body, cute and colorful that we cannot seem to forget.

Seeing the character designs that are on the cover of this game, we sometimes have immediately argued that this game is definitely for children. This game can be categorized easily, but also very complex.

This is because of the development of the characters, the interaction of the main characters with supporting characters, as well as interesting and surprising events. For example, when the main character meets a goddess who lives in a waterfall lake, then chooses a partner for family.

Worth to Replay

Harvest Moon also offers unique festivals held in the village where you live that you shouldn’t miss out. One of the events is Chicken Sumo, where we will pit our livestock chickens to compete with other character’s chicken sumo.

In addition, there are also horse races, cooking competitions, and tomato throwing war. This uniqueness has brought a very large number of fans. Even today, people are still playing this game, either on PC, smartphone, or emulator.

It is undeniable; the replay value is very high, making some of us feel at home to play it. The number of unlimited scenarios and various hidden secrets that are packaged in such a way by Natsume as a developer is also one of the reasons why this game is so memorable.

Well, if you want to reminisce about your childhood, or even try playing this game for the first time, you should do it! Harvest Moon is a legendary game that should always be replayed at any time!

To complete the main story of Harvest Moon: Back to Nature, you must carry out all these repetitive activities for up to 3 years in the game, with one year there are four seasons, and one season has 30 days.

If you are in one room, then the hours in the game will not increase at all, but if you walk in the middle of the city, the beach, or the mountains, then the running time can be said to be very fast.

So, if you want to play this game again, you should consider the length of time to finish it. However, it will definitely a blast to go through it all over again and be nostalgic throughout the years in the game! All this must be achieved within three years, and if you cannot fulfill the conditions requested, you will be told to leave the city of Harvest Moon.

 

Let’s Enjoy the Beat with These Musical Games

Music is an important part of the game as the sounds in the game can revive the atmosphere when you play. Musical games began to exist as games with music as the main element. These games will need your ears to be sensitive to the tone and tempo in music.

Several mobile games have also begun to display such gameplay. You can play all these music games through your smartphones, from the simple ones to those with great background stories!

Starting from Tap Tap, which is a very easy, simple, yet very addictive game. With such a large collection of songs, especially pop songs, you will definitely can’t stop playing the game. The songs on Tap Tap Music-Pop Songs aren’t just pop songs.

You can also enjoy Kpop, Rock, Hip Hop, EDM, and classic songs. The game has a number of levels that must be passed by each player, so you will keep being challenged to flow with the perfect rhythm.

The Classic Music Games

Piano Tiles 2 was once viral because of its addictiveness while only offering simple gameplay. You are required to listen to the song while you tap on the blocks. In a way, you will feel like you are playing the piano with your fingers.
To make it even more like a piano, instead of using your thumbs, use your four fingers instead. Adjust to the rhythm and follow the songs, from classic to the other variations they offer. With over 200 songs, 400 variations as well as 9 difficulty levels, Cytus is one of the musical games that you should play.

The song genres vary from pop, jazz, hardcore, trance to others, so you can pick your favorite and play the game right away. Besides being lulled by an addictive music game, you will also be spoiled with cool visuals. The concept carried in the story is the world of the future that has something to do with robots.

Role-Playing Musical Games

Lost in Harmony offers great music as well as a powerful story that will excite you. In this game, there are two interesting stories for you to choose, namely Kaito’s Adventure and MIRAI’s Escape.

Kaito’s Adventure lets you get into the love story of Kaito and Aya. MIRAI’s Escape is a story about a robot who is exploring the universe. Both stories require you to listen carefully to the music and follow the rhythm, where you need to tap on the beat to avoid obstacles.

Lanota brings unique gameplay to mobile music games by carrying out the concept of a storybook. You will be invited to an adventure where you need to restore the balance of the world through music.

Meanwhile, the game also offers many levels with a neat animation. There will be a boss feature that you must conquer. This is the best option if you like a role-playing game because you get both that and the musical games!
Whether it’s work or school, it certainly requires a lot of energy, thought, and time so that the chances of emergence of saturation are very high. Games can indeed be used to kill fatigue that can be present at any time. But now the game is not only used for this. Without waiting for any fatigue, people will calmly play games from their respective smartphones.

Playing alone, or in groups. There are many choices of games that can be played, one of which is a music game. Music is the life of many, and having them rejuvenate your senses through games is a great way to spend those spare times of yours. These musical games are great for kids as it has a positive effect on their development.

 

Data and Information Quality Issues

A universal concern with all information systems must be the quality of the data contained within them, hence, the well-known adage of the computer age: garbage in, garbage out. Nevertheless, it should be recognized that “errors and uncertainty are facts of life in all information systems” (Openshaw, 1989). The process of describing aspects of reality as a file structure on storage media requires a high level of abstraction, as was illustrated in Chapter 2. Thus, any attempt to completely represent reality in GIS, while no doubt resulting in robust and flexible data sets, would also result in large, complex, and costly data sets that would require a higher order of technology to handle them.

Historically, a detailed consideration of data quality issues in GIS lagged considerably behind the mainstream of GIS development and application. This is evident from the growth of the relevant literature, which underscores a sudden vogue in spatial data quality research from 1987 onward, some 25 years after the introduction of GIS (Figure 8.1). This lag in concern for spatial data quality may be attributed to:

The inherent trust most users have in computer output, particularly after some complex analysis.

The possible lack of awareness among operators and managers from nonspatial disciplines of the sources of uncertainty in spatial data sets and the consequences of propagating them through analyses, other than the need to correct blunders.

The growing desire in the late 1980s for remote sensing (RS) and GIS data integration, there having been already a body of research on accuracy assessment of RS data.

The growth of GIS through stages of inventory, analysis, and management (Crain and Macdonald, 1984) such that a need to consider the consequences of uncertainty in outcomes on decision making may only become apparent after some years of system development. Data are usually collected within a specific context and the design for any primary data collection is usually specified within that context. Surveyor and user may be the same individual, part of the same team or linked by contract.

Thus, the chances for misinterpretation of outcomes or misconceptions concerning accuracy of the data should, in theory, be quite small. But, data are likely to have a life span (shelf life) well beyond the original context and may well be used as secondary data on other projects. Those who collected the data may be unaware of subsequent uses (or misuses) to which their data are put. Most of the early literature on GIS data quality was concerned with the accuracy of data sets, or more specifically, the recognition and avoidance of error. We will be taking a wider view of this issue by considering the level of uncertainty that exists in the use of spatial data and the fitness-for-use of GIS outputs.

Error is the deviation of observations and computations from the truth or what is perceived as the truth. This assumes that an objective truth can be known and measured. Statistically, errors may be identified as gross (outliers, blunders), systematic (uniform shift, bias), or random (normally distributed about the true value).

Reliability concerns the trust or confidence given to a set of input data on the basis of available metadata (data about the data: its lineage, consistency, completeness, and purported accuracy) and upon inspection of the data by the user. It refers to the assessed quality of the data on receipt. The user can then judge its appropriateness for use in a particular context. Fitness-for-use, however, refers to the assessed quality of the products of analyses used in decision making. Such evaluations and judgments must necessarily be the responsibility of the user (Chrisman, 1982).

Where only a single theme is used, then fitness-for-use can be judged directly from the data’s reliability. However, where data sets are integrated and themes are combined or transformed, then the analytical outputs are characterized by combination and propagation of the data reliabilities of the individual themes. In as much as research has focused on quality measures for data reliability, progress in the derivation of quality measures, meaningful in the evaluation of fitness-for-use, has been slower.

Uncertainty in its broadest sense can be used as a global term to encompass any facet of the data, its collection, its storage, its manipulation, or its presentation as information that may raise concern, doubt, or skepticism in the mind of the user as to the nature or validity of the results or intended message. Theoretically, this definition would also include mishandling of the data through improper analysis, inappropriate or erroneous use of GIS functions, poor cartographic technique, and so on. Thus, in the context of environmental modeling, Burrough et al. (1996) consider the quality of GIS informational output to be a function of both model quality and data quality.

Modeling issues will be discussed separately in Chapter 9. The term uncertainty, therefore, will be used to refer to the inevitable inaccuracies, inexactness, or inadequacies that exist in most spatial data sets and their resultant propagation through analyses to adversely affect the usefulness of results and certainty in decision making. Four broad categories of uncertainty are given in Figure 8.2. Intrinsic and inherited uncertainties are those associated with primary and secondary methods of data collection (Thapa and Burtch,1990), respectively. Secondary data (e.g., existing maps) will also have an element of intrinsic uncertainty. Once the data are used within GIS, intrinsic and inherited uncertainty will be propagated and additional uncertainty may be derived due to the nature of hardware and software. This is operational uncertainty. The resulting levels of uncertainty, if not quantified or in some way known, may lead to overconfident, uncertain, or erroneous decision making. Uncertainty or error in use may also derive from different perceptions or misinterpretation of the output information on the part of the user.

Cartographic Processing in GIS

MacDougall (1975), writing in the context of paper maps, provided an early warning of what to expect from cartographic processing in GIS: “It is quite possible that map overlays by their very nature are so inaccurate as to be useless and perhaps misleading for planning.” The concern was that maps, whilehaving individually adequate planimetric accuracy and “purity,” may when combined produce a seriously degraded product. Chrisman (1987), however, considered MacDougall’s analysis to be ”dangerously oversimplified.” Another early concern lay with the nature of the data themselves.

Most GIS are reductionist and support parametric forms of enquiry, which force data into well-defined categories even though in reality they may lie along a continuum (e.g., mutually exclusive land use classes or soil types). Boundaries (within and between layers) can be unintentionally misleading in that they imply both spatial homogeneity within a polygon and equal homogeneity for all areas of the same class (Robinove, 1981). Even though methods of classification, categorization, and boundary definition may be known for each layer, their effects on the validity of results due to combination may be very difficult to assess with scope for misinterpretation of the results.

Many of these problems already existed in paper thematic maps. Thus, ”the essence of mapping is to delineate areas that are homogeneous or acceptably heterogeneous for the intended purpose of the map” (Varnes, 1974). This again leads to a reductionist process of defining a hierarchical structure of classes, assigning each individual to a class, and placement of the classified individual in its correct position (Robinove, 1981).

Fixed scale also applies to paper topographic maps and accuracy tests are scale dependent (see below). Transferred to a digital environment certain safeguards inherent in paper maps, such as the fixed scale, were removed, though traditional attitudes toward spatial data persisted: If it wasn’t a problem in the past, so why is it now (Openshaw, 1989)? There is also evidence that many users poorly understood the accuracy of paper maps, often attributing them with higher levels of accuracy than warranted. “Data for which no record of its precision and reliability exists should be suspect” (Sinton, 1978). While there were accuracy standards developed for primary data collection, in secondary data collation (e.g., digitizing of existing maps) the assumption seems to have been that since the source documents were originally compiled to the prevailing standards (or were somehow authoritative), they could also be converted to GIS and used without problem. The ability to change scale in the digital environment and combine data sources at will was viewed only as a positive advantage. There appears to have been little regard for, or understanding of, the cumulative effects of these data combinations on the quality of the informational outputs.

Three widely reported studies seemed to clinch it for the GIS community. Blakemore (1984) tested an actual database of employment office areas and manufacturing establishments for which it was necessary to identify which manufacturer (a point) fell within which employment office area (a polygon); in other words, a standard point in a polygon test. By making basic assumptions regarding data input accuracy for both the points and the digitized polygon boundaries (ε or epsilon band, as illustrated in Figure 8.3), Blakemore found that only 55% of points could be unambiguously assigned. Newcomer and Szajgin (1984) tested error accumulation as probabilities when combining raster data layers. Their conclusion was similar to that of MacDougall (1975): a general rule of thumb that the result of an analysis would generally be less accurate than the least accurate layer used. Then Walsh et al. (1987) extended Newcomer and Szajgin’s analysis by using typical data sets for that time.

By using more than two layers and by varying cell size, they found that errors inherent in the data and additional errors introduced through combining layers led to a sufficient total error to render composite maps highly inaccurate. For two-layer combinations, the highest accuracy was 29% and the lowest 11%, while for three layer combinations, the accuracy ranged from 11% to just 6%. Though the situation today with higher resolution and more accurate spatial data is unlikely to result in such poor analytical products, such studies were nevertheless a very clear indication of the potential seriousness of the problem.

Imperfect Measurement

Equipment used for measurement, whether it be the time-honored tape measure, weighing scales, or advanced uses of the laser beam, all have their design accuracy and level of precision, some equipment requiring calibration before use. Most equipment, if used for repeated observations of the same static object or phenomenon, will result in a cluster of measurements normally distributed around the true value and spread in relation to the equipment’s precision. There is a tendency for this to be compounded by errors or bias in recording measurements. A gross error or blunder, such as putting the decimal point in the wrong place or writing too many zeros, should be noticeable as an extreme value or outlier when all the measurements are graphically plotted, such as by using box plots. Bias often occurs through unintentional rounding of the observations, say upward to the nearest 0.5 or to the nearest integer. Bias can occur if equipment is poorly calibrated or is adversely affected by temperature and/or humidity resulting in a shift in the readings.

These biases tend to result in systematic errors that are more difficult to detect and correct, but which, as we will see later, can compound during analyses and raise the level of uncertainty. It is also worth mentioning here the ‘small number’ problem. This often crops up, for example, in population dynamics when working with proportional data. A population of two that increases by two has increased by 100%, whereas an increase of two in a population of 100 increases by only 2%. Though not a measurement error, this is a measurement scale effect of working with small numbers where proportional increases can appear disproportionately large, but nevertheless result in biased analyses.

Role of GIS in Data Integration

In 1991, digital maps of rural areas were not available. Typically, paper topographic maps are themselves prepared in layers with separate masters for contours, detail (roads, buildings, streams), symbols, and annotation (e.g., place names). Therefore, it was possible to go back to original masters, choose only the contours and the detail layers, which could then be scanned and vectorized. In this way, scanned 1:5000 scale topographic maps, which were then edge-matched into seamless base mapping, were used as the means to co-register and, therefore, integrate all the other data sets. There were five sets of other data:

Historic flood events: Two well-documented flood events (1988 and 1989) were mapped from oblique photographs of the floods taken from a helicopter, from press photos, and from questionnaire interviews of residents. Thus, the flood extents were mapped differentiating certain and uncertain boundaries. These could be used as part of the model calibration.

Drainage structures: This documented the location and attributes of all bridges, weirs, and culverts that would influence channel flow. These were collected by field survey during which channel cross sections were measured to be input directly to the simulation model.

Sub-basin parameters: These were a series of map layers derived mostly from API to produce the lumped parameters at modeling nodes. These are discussed in detail below.

Floodplain elevations: Spot-heights were digitized from 1:1000 topographic maps in order to build up detailed floodplain DEM so as to extend the field surveyed channel cross sections to the edge of the floodplain, but also to act as a key data layer in the postprocessing of the simulation outputs.

The process of preparing the lumped parameters for the simulation modeling is as follows. A land use classification is created that reflects run off characteristics and which can be consistently equated to the U.S. Soil Conservation Service’s (SCS) runoff curve numbers (CN). These are numbers in the range 0 to 100 and can be loosely interpreted as the proportion of rainfall contributing to storm runoff depending on the nature of soils and Vegetation. In the Hong Kong case, with intense rainfall on steep slopes that quickly exceeds the infiltration capacity, runoff is most influenced by land cover types rather than by soil types, which thus were not mapped separately. The highest CN is usually assigned to urban areas where there is little infiltration or storage, a low CN would be assigned to woodland, and the lowest to, say, a commercial fish pond where all the rainfall is retained within the pond.

Eighteen classes of land cover were mapped by API and digitized into GIS. There is a tendency for tropical terrain to be characterized by a distinct break of slope between the steeper mountainous terrain and the gently sloping valley floors (noticeable in Figure 6.6 and Figure 6.7). This is an important feature in the simulation modeling that needs to be distinguished if realistic unit hydrographs are to be developed and so this too was mapped as a polygon boundary between “upland” and “lowland” zones.

Land cover polygons together with upland and lowland areas for a small catchment are given in Figure 6.9(a). The engineers would identify the proposed locations of modeling nodes. These would be screen digitized into GIS and snapped to the drainage network.

The hydraulic modeling used for the flood simulation was pseudo 2D, solving the full St. Venant equations to simulate variations of flow in space and time. The St. Venant equations assume that channel discharge can be calculated from the average cross-sectional velocity and depth and are based on a mass balance equation (6.1) and a momentum balance Equation (6.2), which assumes that water is incompressible (Beven, 2001):

where A = cross-sectional area, P = wetted perimeter, v = average velocity, h = average depth, So = bed slope, I = lateral inflow per unit length of channel, g = gravitational acceleration, f = the Darcy–Weisbach uniform roughness coefficient.

In the pseudo two-dimensional approach, flow along reaches is modeled as 1D (at a node) using mean velocities, whereas overflow into floodplain storage and flow can also be simulated at representative nodes. Structures, such as bridges, weirs, and dams, are fully described. Calibration of the models was achieved using historical rainfall data and corresponding data from gauging stations giving velocity and stream level at a number of locations and by reference to the historic flood extents mapped in GIS.

Output from the simulation is a time series for each node giving the height and the velocity of the flow. Since the simulation output refers to a series of points (the nodes), the data need further processing in order to visualize the flood extents and assess the impacts.

Figure 6.10 summarizes this postprocessing carried out in GIS. At the time it was not possible to use the entire simulation output of height and velocity. Today, this could be resolved as a series of multiple maps brought together in an animation to show the progress of the flood from initial rise until it drains away. But, in 1991, that technology wasn’t quite with us and with the need to evaluate multiple scenarios, time was tight anyway.