Massive Detailed 3D Geographic Information Collection on the Web

Zengshi Huang, Naijie Gu and Jianlin Hao

Department of Computer Science and Technology, University of Science and Technology of China, Hefei, China

Keywords:

Detailed 3D Geographic Information, Web3DGIS, Volunteered Geographic Information.

Abstract:

Detailed three-dimensional (3D) geographic data are important for many kinds of spatial analysis and applica-

tions. However, professional Computer Aided Design (CAD) tools are essential to construct 3D models when

collecting these data. As a result, the collection is limited to computers and professional persons in both com-

mercial projects and Volunteered Geographic Information (VGI) projects. This paper presents a new system

for detailed 3D geographic information collection through VGI. The system combines Web3D Geographic

Information System (Web3DGIS) and a template based CAD methodology on the web. Based on Extensible

3D (X3D) and X3DOM, it is applicable for both computers and mobile devices and extends the collection

to a large number of non-professional VGI contributors. With a methodology to transform the collected data

into international standard CityGML format, massive detailed 3D geographic information collection will be

achieved.

1 INTRODUCTION

In the last several years, there is an increasing inter-

est in a 3D representation of the Earth in the world

of GIScience. As a part of the source data, detailed

3D geographic information including openings (win-

dows, doors) of the building and indoor environments

is essential for many kinds of applications and spatial

analysis such as environmental noise pollution and in-

door navigation (Kolbe et al., 2005; Goetz, 2013).

Volunteered Geographic Information (VGI) is

geodata contributed by individuals who act as re-

mote sensors (Goodchild, 2007). The Open Geospa-

tial Consortium (OGC) standard CityGML deﬁnes

Level-of-Detail (LOD) of the building. LOD0-LOD2

represent the building with details no more than a

simple block and roof types. LOD3 is intended for

openings and LOD4 for indoor environments (Kolbe

et al., 2005). At present, massive collection for

3D geographic information is achieved up to LOD2

through VGI projects and technologies. Examples are

OpenStreetMap (Goodchild, 2007), Google Building

Maker

and LiDAR (Verma et al., 2006). Even

though some of them have high resolution textures

for openings, no structure information of openings

for spatial analysis can be achieved. For details

up to LOD3 and LOD4, professional CAD tools

are required for both VGI projects and commercial

http://en.wikipedia.org/wiki/Google Building Maker

projects (Goetz, 2013). As a result, detailed 3D geo-

graphic information of the world is quite limited.

This paper introduces the data structure, the

methodology and the implementation of a new system

to collect detailed 3D geographic information. The

system depends on the VGI project OpenStreetMap.

Based on X3D and X3DOM, the system is native to

browser. It can run on both computers and mobile de-

vices. An easy-to-use template based CAD methodol-

ogy is introduced. It allows volunteers of VGI to edit

the 3D models and review the changes in real time.

When the editing is ﬁnished, the detailed 3D infor-

mation is generated and submitted. In this paper, we

promote the details from LOD2 to LOD3 through the

new system.

The capability to be applicable for mobile devices

is signiﬁcant for the system. There is a trend that mo-

bile devices are equipped with more sensors. These

sensors can be used to measure more detailed 3D ge-

ographic information. One example is the Google

Tango project. The project has provided mobile de-

vices for 3D measurement

. The system here pro-

vides a more friendly platform for non-professional

contributors of VGI. Through it, they can edit the

building and submit the model on mobile devices. For

Openstreetmap, there is no efﬁcient web 3D editor at

present. The system solves the problem. It is expected

to extend Openstreetmap to a detailed 3D map. With a

https://www.google.com/atap/project-tango/

Huang, Z., Gu, N. and Hao, J.

Massive Detailed 3D Geographic Information Collection on the Web.

In Proceedings of the 12th International Conference on Web Information Systems and Technologies (WEBIST 2016) - Volume 1, pages 95-104

ISBN: 978-989-758-186-1

large number of VGI contributors all over the world,

collection for massive detailed 3D geographic infor-

mation is coming true.

The paper is decomposed in the following sec-

tions. Section 2 makes a review of the related work

about 3D VGI, web 3D technologies and the pro-

cedural modeling method. Section 3 introduces the

methodology of our system, the template based CAD

and template management. Section 4 presents the de-

tails of the implementation. Section 5 shows the re-

sults and evaluations of the system. Section 6 gives

the conclusions and talks about the future work.

2 RELATED WORK

VGI improves the traditional top-down geographic

information developed by commercial organiza-

tions, professional institutions and governments. It

is bottom-up geographic information (Goodchild,

2007). With contributors all over the world, VGI

projects collect a large quantity of geographic infor-

mation in near real time. WebGL (Marrin, 2011) and

related web 3D technologies make it possible for real

time cross-platform rendering. Procedural modeling

can generate 3D models from a few parameters with

pre-designed principles.

2.1 3D Volunteered Geographic

Information

OpenstreetMap (OSM) is one of the most popular

VGI projects. It has become stronger since it was ﬁrst

presented. In 2015, the number of contributors for

OpenStreetMap reaches over 2 million

. The OSM

data are quite competitive regarding quality and quan-

tity, especially in urban areas (Over et al., 2010)

The data format of the OSM project is XML based

language. Extensions to represent and store 3D infor-

mation for OSM have been proposed. It is possible to

edit LOD0-LOD2 details in current web OSM editor.

For more details in LOD3-LOD4, the key building-

part is proposed. The extensions are expected to be

accepted by the OpenStreetMap community in the fu-

ture (Goetz and Zipf, 2011).

The 3D information in OSM is a reasonable data

source even for professional applications and spatial

analysis. From the OSM data with 3D extensions, it

is possible to generate CityGML models in different

LODs automatically (Goetz, 2013). Visualization of

the OSM 3D information in GIS has been introduced

http://www.openstreetmap.org/stats/data stats.html

and implemented in the OSM-3D project (Over et al.,

2010).

Google Building Maker (GBM) is another famous

VGI project. GBM has the capability to construct

low LOD 3D models with high resolution textures.

For details in LOD3-LOD4, professional CAD tool

Google SketchUP is essential. Besides, no automatic

methodology is available to generate CityGML mod-

els from the data in GBM. GBM retired in 2013 and

only Google SketchUP is available to construct build-

ing models at present.

2.2 Web 3D Technologies

Plugins were widely used to visualize 3D models on

the web in the past. In plugin mode, the users have

to install speciﬁc plugins to their browsers for spe-

ciﬁc applications. Problems including security and

incompatibility issues come with them (Behr et al.,

2009). WebGL is a standard for real time rendering

on the web. It is based on OpenGL ES 2.0 API with

accession to hardware for better performance. Ex-

posed through the HTML5 Canvas element as Docu-

ment Object Model interfaces, WebGL is widely sup-

ported by most browsers. It is a cross-platform web

standard with no plugins needed (Marrin, 2011).

There are a set of 3D model formats such as

COLLADA and X3D. They can reach the browser

through plugins, HTML5 and WebGL. COLLADA is

a 3D-ﬁle standard for content exchange. With high

compression ratio and high portability capabilities it

performs well on representing and storing 3D mod-

els (Arnaud and Barnes, 2006). The speciﬁcation of

X3D includes a runtime environment and deﬁnes an

event-model. This allows users to deﬁne the behavior,

content and interactive elements of the X3D model.

Moreover, the Scene Access Interface (SAI) is deﬁned

in X3D speciﬁcation. With SAI, users can control the

scene from a script in the scene itself or from external

applications (Web3DConsortium, ). With interfaces

for user interaction, X3D is more suitable for CAD in

this paper.

X3DOM is a framework based on WebGL for the

integration of X3D and HTML5. It is implemented by

a tightly DOM-based integrated model. The imple-

mentation makes it possible to synchronize live DOM

elements to X3D scene (Behr et al., 2009). A vari-

ety of DOM changes are available through JavaScript

DOM API (e.g inserts/removals of element and at-

tribute changes). Through X3DOM, these DOM

changes will be synchronized to the X3D scene in real

time. Besides, a fallback model for different types of

events (e.g key, mouse, HTML and mutation ) is ex-

plained and implemented (Behr et al., 2010). For the

WEBIST 2016 - 12th International Conference on Web Information Systems and Technologies

system, X3DOM makes it possible to visualize and

edit the X3D models in real time. No plugins are re-

quired.

2.3 Procedural Modeling

Procedural modeling (PM) automatically generates

content through procedure or a program. It is widely

used in games, movies and simulations. With PM,

we can generate a large number of detailed content

with less human intervention. As introduced in (Sme-

lik et al., 2014), there are methods to generate differ-

ent features of the virtual world, including buildings,

roads and cities.

There are several signiﬁcant features of PM. Only

a few input data are required for PM. PM generates

models through a few generation rules or a simple

set of input parameters, or both of them. With these

input, PM can generate a large number of different

models. Another feature of PM is data compression.

In PM, the complex geometric models are represented

by procedural models and a set of parameters. Only

when necessary, the actual geometry is generated. PM

can reduce the amount of modeling effort to create

complex models. We only set the parameters. All the

output of PM models are generated with these param-

eters automatically.

In (Patow, 2012), an user-friendly graph editing

for procedural modeling of buildings is introduced.

Complex building models can be generated in a few

steps. Firstly, the building are divided into differ-

ent components, including windows and doors. The

model for each component are designed and stored in

the system ahead. Then the components are inserted

into the wall by setting parameters. At last, the com-

plex building model is generated. In this paper, we

implement a template based CAD methodology based

on PM.

3 METHODOLOGY

In this section, we introduce our solution for detailed

3D information collection together with the template

based CAD methodology. Then the management of

the large number of templates of the system is intro-

duced. The management is to represent and reuse the

template efﬁciently. In the third subsection, two key

data structures of the system are shown in detail. One

is to edit 3D models on the client side. The other is to

represent and store the collected 3D information on

the server side. At last, we explain the principle to

handle the conﬂict data and the precision problem of

the collected data.

3.1 The Solution

We provide our solution to the limitation of detailed

3D geographic information collection — a new sys-

tem that combines GIS and CAD on the web. The

methodology is based on web 3D technologies X3D

and X3DOM, the VGI project OpenStreetMap, the

OGC standard Web 3D Service and the open source

database PostGIS. Figure 1 shows the six main phases

of the system, VGI storage, model generation, model

storage, visualization, model editor and VGI genera-

tion.

The OSM data are stored in database (VGI stor-

age). Then LOD1-LOD2 3D building models are gen-

erated automatically (model generation). To reduce

the complexity of Web 3D Service, all the 3D mod-

els are stored in a 3D database (model storage). The

client asks for the 3D models from the server and ren-

ders them (visualization). The users edit the 3D mod-

els for more details. They can review the changes in

real time (model edit). Finally the detailed 3D VGI

information is generated and uploaded to the server

(VGI generation).

Model Storage

VGI Storage

VGI Generation

Model Editor

Model Generation

Visualization

Web 3D Service

x3dom

Figure 1: The methodology of the solution.

Select

building

All surfaces

edited?

Select surface

beginBegin

Select template

Begin

Select base

template

Set

parameters

Add

template

End

Yes

Set position

Add to the model

All details

edited?

End

Yes

Template

available?

Yes

End

Edit

building

Edit

building

Edit

surface

Edit

surface

Edit

template

Edit

template

Edit surface

Figure 2: The template based CAD methodology.

In this paper, We provide the method to gener-

ate different components of the building. A tem-

plate based CAD methodology is proposed based on

PM. There is no complex design in this methodol-

ogy, which makes it more friendly to non-professional

Massive Detailed 3D Geographic Information Collection on the Web

contributors. As shown in Figure 2, there are three

main parts of the CAD methodology, edit template,

edit surface and edit building. Base templates for the

detailed information are stored in the system. Tem-

plates will be generated by simply setting proper pa-

rameters to the base template. Each surface is edited

by selecting templates and setting the right relative

positions of them. When all surfaces of the building

are edited, modiﬁcation of the building comes to an

end. All the operations above are only selecting com-

ponents and setting parameters for them. Any user

will be familiar with them in a few minutes.

3.2 Management of Templates

The template based CAD methodology is depending

on the templates. With more and more templates

edited, there will be an increasing problem in man-

aging the templates. Here we will introduce three

different principles of managing the templates: base

templates, user based templates and location based

templates. The managements reduce the steps for the

volunteers to edit the building by reusing the existing

templates. On the other hand, the data size will be re-

duced by merging the duplicate templates. Storage is

saved on the server side. On the client side, they prove

to be quite efﬁcient in the following tests ( Figure 7 ).

3.2.1 Base Templates

Base templates are the basis of all the templates. They

are designed and stored in the system. They represent

the base components of the buildings, such as win-

dows and doors. Base templates have the framework

of the components. A few variables are left to modify

different templates. Taking doors for example, doors

have width height and style variables. The style can

be wood or glasses. By setting these variables, the

Base

Template

Figure 3: Examples of different templates generated from

one base template and their usage in the building.

system generate different door templates. At present,

we set two simple base templates for tests. In the fu-

ture, base templates will be got from volunteers all

over the world and approved by the manager of the

system. In Figure 3 , we generate a few windows and

doors from one base template and use them to modify

the building.

3.2.2 User based Templates

User based templates is an important feature of the

system. For each user, the system will store all the

templates that have been generated or used by the

user. When a building is modiﬁed, any user is allowed

to reuse the component templates of the building. The

system allow the user to select an existing template

in the modiﬁed building and add it to his own tem-

plates store. In this way, the existing templates will

be reused and greatly simplify the work of users. On

the other hand, reusing the templates means less stor-

age of the system on the server side. One template

has only one storage on the server side. Less effort is

required to manage the templates on the server side.

This is quite important as the templates grows in the

future.

3.2.3 Location based Templates

Another important feature of the system is the lo-

cation based templates. Similar to the user based

templates, the location based templates are to reuse

the existing templates. We create this kind of tem-

plate management based on the fact of our real world.

Buildings in our world are of different styles. In many

cases, buildings in the same city or in the nearby area

have similar appearance. Their components are of the

same appearance and the same parameters (eg. width

of the door, height of the door). Examples are shown

in Figure 4. On the left are two laboratories in the

university. On the right are several buildings in the

residential area. The building components in red cir-

cle are of the same template. With the observation, we

provide the location based templates. In section Tests

and Evaluations, it is proved to be quite efﬁcient when

the user do not have enough user based templates.

Figure 4: Examples of same templates based on location in

real world.

WEBIST 2016 - 12th International Conference on Web Information Systems and Technologies

The location based templates are generated by the

system without any interaction from the users. The

whole process works similar to a location based ser-

vice. When we are editing a building, the system

computes a rectangle with length and width of 2000

meters ( an experimental value ) centered at the build-

ing. Then all the buildings in the rectangle are com-

puted and selected from the OSM database. The tem-

plates used in these buildings, indexed by id, are de-

tected and ranked by the frequency used in different

buildings. At last, a list of ranked templates are re-

turned to the client side, which are the location based

templates shown in the client interface.

3.3 Data Structure of the System

Two new data structures are the key features of the

system: Editable X3D ( E-X3D ) and OSM extensions

for templates. E-X3D makes it possible to edit the 3D

model on the web while OSM extensions is designed

to represent and store the proposed templates of the

system.

3.3.1 The E-X3D Format

To be editable, three features are essential for the

3D models. Firstly, the component of the 3D mod-

els should have the feature to be selected; Secondly,

the data of the selected component can be changed;

Thirdly, these changes to the component can be syn-

chronized to the scene in real time. In (Behr et al.,

2009; Web3DConsortium, ; Behr et al., 2010), de-

tails have been introduced about how to make the 3D

model response to the users with X3D and X3DOM.

When loaded, X3D models are in the format of a

DOM tree. HTML DOM object makes it possi-

ble to select speciﬁc component by id in the DOM

tree. Leveraging these features of X3D, X3DOM and

HTML DOM object, we extend the X3D to the E-

X3D.

For building models in E-X3D, special contents

are added. Each building and each surface of the

building are grouped separately with X3D Group tag.

The Group tag of each building has one globally

unique id and each component of it has one unique

id locally. The globally unique id is created from the

OSM id of the building. Besides, An onclick function

with id as parameters is added to each Group. The

function responses operations from users. With these

extensions, the models are of E-X3D format and ed-

itable. Example of the editable building in E-X3D is

below.

<Group id = ’building_131’ onclick =

"edit_building(’building_131’);">

<Group id = ’wall_0’ onclick =

"edit_wall(’wall_0’);">

/* Content for the wall */

</Group>

/* Content for other walls and roofs */

</Group>

Wrapped in E-X3D format, the building and the

wall will be selected in the DOM tree by the speciﬁed

id on click of users. We can change the content of the

DOM tree through the HTML DOM object. At last,

changes are synchronized to the scene in real time.

3.3.2 OSM Extension for Templates

When we add the new extensions, the most impor-

tant thing is that we have to make them compatible

with the existing 2D OSM data. Following the OSM

shcema, we only use nodes, ways, relations and key-

value pairs for all kinds of data and information.

In this paper, we present a new methodology to

represent a detailed 3D building extended from the

one introduced in (Goetz, 2013). Motivated by PM,

we provide a new way to represent the 3D informa-

tion for openings of the building. We do not attach

a key-value pair tag for each parameter of the open-

ings. Instead, we divided the openings into different

styles. For each style, we design the methodology

to generate the 3D model and ﬁgure out which pa-

rameters are required. Then we give the key to rep-

resent the opening style and the parameters. In this

way, when we face a new opening style, we do only

need to design the methodology and ﬁgure out the

parameters. No more new keys is required, which

will avoid the potential key explosion in OSM. We

proposed four more keys for the 3D model of win-

dows and doors. Details are listed in 1. The tem-

plate:id key is used when the template is referenced

in the building. Information of the opening style is

represented by basetemplate:id and opening parame-

ters by basetemplate:parameters key. For example,

the two parapemters of the base template 1 represent

the height and the width of the model. When we gen-

erate a window model with basetemplate:id=”1” and

basetemplate:parameters=”3,1”, the result is a win-

Table 1: Proposed keys for detailed 3D models.

Key Description

Exemplary

Values

template it is a template yes

template:id

the reference id

of the template

1,1000

basetemplate:

the reference id

of base template

1, 2

basetemplate:

parameters

parameters of the

base template

”3 3 0.1”

Massive Detailed 3D Geographic Information Collection on the Web

dow with height of 3 meters and width of 1 meters.

The two new basetemplate keys only represent the

3D information of the template itself. The 3D infor-

mation of the template in real world is attached by

key-value pair tag when the template is used. In the

following code we show how to represent and use a

window in OSM with the extensions. The position of

the template is where the template was ﬁrst created

and used. The breast of the window is attached by

tags buildingpart:window:breast when the template

is used.

<node id="224524350810" lat="31.8341438"

lon="117.2960426" buildingpart:window="yes"

template="yes" user="tom" basetemplate:id

="1" basetemplate:parameters="3,1"

<node id ="224524350820" lat="31.8341438"

lon="117.2960426" user="tom"/>

</node>

The new design is compatible with OSM. All the

data are directly stored in the OSM database. For new

3D features and more complex 3D features, we do

not need more new keys. It will avoid the key ex-

plosion when we try to represent the complex real

world in OSM. Besides, the template will be reused.

For a window template, it may be reused for tens of

times in one building, even reused for thousands of

times in the whole city. With the extended method-

ology, we reduce the effort to modify the building

component and storage on the server side by reusing

the existing template. The data with new extensions

can be transformed into OGC standard data. For each

base template, the 3D information is stored in the pa-

rameters. The methodology and principle to generate

CityGML models from the parameters are designed

ahead. Then following the principles introduced in

(Goetz and Zipf, 2011), we can generate detailed 3D

building models in CityGML format.

3.4 Principles and Precision

3.4.1 Principles

As this is a system to collect detailed 3D information

from volunteers, there is a chance that two different

persons modify the same building. It is similar to the

current 2D OSM editor. In this case, the system han-

dles the data as what the 2D OSM editor does. All the

data are stored in the database. Each data are attached

with key user and timestamp to represent the editor

and the time edited. The latest data are shown to the

user. The principle applies to both the building data

and the template data to solve potential conﬂicts. We

assume that the new data are to correct some errors in

the previous data. The principle proves to be simple

and efﬁcient. At present, following this principle, the

2D OSM data are reliable (Fan et al., 2014).

3.4.2 Precision

Another problem is the precision of the collected data.

A lot of persons question the quality of the VGI

data. The problem of precision mainly comes from

two aspects. One is that the volunteers have no re-

liable methods to measure the 3D information. The

other is that the volunteer is careless and not reliable.

For the ﬁrst aspect, there is a trend that mobile de-

vices are equipped with more sensors for 3D mea-

surement. A experimental device of Google Tango

project has been produced. In the future, we believe

that there will be reliable tools in mobile devices for

3D measurement. For the second aspect, experiments

have been done to evaluate the quality of the data in

OSM (Fan et al., 2014). Results show that the pre-

cision of building footprints in OSM is reliable com-

pared with the authority data in Germany. The volun-

teers are trustworthy. The 3D information from vol-

unteers is expected to be reliable.

4 IMPLEMENTATION

The target of this paper is a widely-applicable sys-

tem for detailed 3D Geographic collection. The func-

tions of this system consist of storing 3D informa-

tion on the server, visualizing low LOD 3D models

on the web, modifying the models with more details

and generating detailed 3D VGI to upload. The users

of this system - the contributors of VGI may be non-

professional and know nothing about GIS or CAD. To

achieve the target, the following features have to be

satisﬁed. 1. The client of the system should be imple-

mented on the web regardless of platforms. 2. There

should be an easy-to-use tool to edit the models and

review the changes.

Figure 5 shows the architecture and workﬂow of

the system. VGI storage, model generation and model

storage are implemented on the server side, together

with the OGC standard Web 3D Service (W3DS). On

the client side, there are three components based on

X3DOM, a load manager controlling the scene to load

and rendered; an editor interacting with X3DOM to

edit 3D models and review the changes; a generator

used to generate VGI data from the operations and

upload the data to the server. The client requests low

LOD 3D models from the server through W3DS and

WEBIST 2016 - 12th International Conference on Web Information Systems and Technologies

100

Server

Data Storage

OGC Web

Service

Client

Browser

Editor

Templates

Management

VGI

Database

3D Model

Database

W3DS

Request

Acceptor

Import

Generator script

Load

Manager

Generator

OSM data

XML

Get Scene

X3D

X3DOM

Edit

changes

X3D

User

Database

Reference

1. Base Templates

2. User based templates

3. Location based

templates

Template

Data

Stored in

Figure 5: The architecture of the system.

uploads the detailed 3D information in return. De-

tailed implementation of the system is explained in

section Server and Client.

4.1 Server

The server of the system has three databases, one VGI

database to store the VGI data; one 3D database for

3D models; one user database to store the user infor-

mation. As the template data are completely compat-

ible with the OSM data, they are stored directly in the

VGI database.

The generating process from OSM data to 3D

models is quite complex. It takes too long for real

time web service. To get better performance of

the server, the 3D database is introduced .The data

streaming between VGI database and 3D database is

achieved by a generator script based on the method-

ology introduced in (Goetz, 2013). The Web 3D Ser-

vice (Schilling and Kolbe, 2010), which is an OGC

standard, is implemented to exchange 3D models be-

tween the server and the client. It gets the requests

from the client and decodes the requested data from

the databases. Then the data are generated in E-X3D

format and returned to the client.

An accepter to response the uploaded data is im-

plemented on the server. If the detailed 3D data pass

the basic correctness check, they will be imported into

the VGI database.

4.2 Client

The functions of the client consists of the followings,

visualizing the 3D models to users; editing the 3D

models with detailed information and generating de-

tailed 3D information into OSM data format to upload

to the server. These functions are achieved by load

manager component, editor component and generator

component.

The load manager controls the loading process

of the models. It calculates the square to down-

load based on the viewpoint position. The stan-

dard W3DS GetScene request is used to request 3D

models from the server. To overcome the preci-

sion problem of the ﬂoating point number of We-

bGL (Web3DConsortium, ), the load manager trans-

forms the X3D models into local coordinate built

based on the viewpoint position.

The editor interacts with X3DOM to edit the 3D

models. The template based CAD methodology is im-

plemented. In most cases, openings of the same tem-

plate in one surface distributes regularly. We leverage

this feature to simplify the operations. The users only

set two types of parameters. One is the number of

columns and rows. The other is the distance between

adjacent rows and adjacent columns. The positions

of the template are calculated by the editor. When

editing models, the editor stores the details in a DOM

tree. Then changes are calculated and added to the

X3D models. A preview window is implemented to

review the editing template or the selected template.

This will prevent some errors when editing the build-

ing.

When the building is modiﬁed, the generator com-

ponent gets the detailed 3D information from the

DOM tree structure. Then the information is trans-

formed into global coordinate and generated into

OSM data format. Finally it is uploaded to the server.

5 RESULTS AND EVALUATIONS

This paper presents a web based system to visualize,

edit and collect detailed 3D information for OSM.

Compared with other VGI projects and commercial

projects, the new system makes it possible to edit de-

tailed 3D geographic information in web based 3D

environment. The platforms to edit 3D models are ex-

tended to mobile devices. The operations to edit the

models are simpliﬁed for non-professional VGI con-

tributors. A prototype of the system is implemented

for tests.

A B

Figure 6: Editing the 3D building model on different plat-

forms. A. On Iphone6S . B. On a personal computer.

Massive Detailed 3D Geographic Information Collection on the Web

101

Tests for both computers amd mobile devices are

implemented. The result is shown in Figure 6. The

surface of the building in red color is on editing.

5.1 Performance Tests

Three types of performance tests are designed. 1.

Tests on computers and mobile devices to compare

the performance between different platforms. 2. Tests

on the same platform with different browsers to get

the inﬂuence of browsers. 3. Tests on the initial low

LOD models and the edited models to get the effect of

the editing operations on performance. For the com-

puter platform, it is a personal Lenovo computer with

CPU i5-3470 3.20 GHz. The graphical card is Nvidia

GeForce GT620. The operating system is Ubuntu

12.04 64bit. For the mobile platform, it is Iphone6s

with IOS 9.0. The browsers are Chrome 38.0 and

IOS Safari 9.0, which fully support the WebGL stan-

dard. As this paper focuses on details, ten buildings

are loaded. The size of the X3D ﬁle is 154.9KB. Ex-

tra data are 64 pictures as textures. Details of the

tests are shown in Table 1. The editing operations

add 316 templates including windows and doors to

the building model. Status initial stands for before

the editing operations. Status edited stands for after

the editing operations. The FPS is the average frame

per second when navigating the model. The system

runs smoothly on different platforms.

Table 2: Tests on different platforms.

Id Platform Browser Status FPS

1 Lenovo Chrome 38.0 initial 55.9

2 Lenovo Chrome 38.0 edited 55.6

3 Iphone6S Chrome 38.0 initial 34

4 Iphone6S Chrome 38.0 edited 32

5 Iphone6S Safari 9.0 initial 35

6 Iphone6S Safari 9.0 edited 34

There is a big performance advantage in comput-

ers compared with mobile devices (1 and 3, 2 and

4). Different browsers on the same platform have

some differences. The differences come from the ef-

ﬁciency of their WebGL implementations (3 and 5, 4

and 6). Considering the editing operations, there is a

slight drop in performance on mobile devices while

nearly nothing on computers (1 and 2, 3 and 4, 5 and

6). These tests show that the performance of the sys-

tem mainly depends on the platform and the browser.

The editing operations in the system will only inﬂu-

ence the performance slightly on mobile devices. The

client runs smoothly on the web on all the tested de-

vices. Both the computers and the mobile devices can

meet the requirement of the client.

5.2 Effciency Evaluation

The number of operations to modify a building can be

calculated by Eq 1.

N = NT +

∑

i=1

NT S

∑

j=1

NIR (1)

N stands for the total number of the editing opera-

tions. NT is the number of different templates of the

building. NS is the number of surfaces. NTS is the

number of different templates for each surface and

NIR is the number of irregular position modes of the

same template in one surface. The building edited in

Figure 6 B has 33 surfaces, 312 windows and 4 doors.

The variables of the building in Eq 1 are as follows,

NT is 9, NS is 33, NTS ranges from 0 to 2 and NIR

ranges from 1 to 2. The building is edited in only 43

steps.

We also evaluate the template management

method of the system. When the user has the tem-

plates to modify the building, there is no need to mea-

sure the building component and modify the template

for another time.

N =

∑

i=1

NT S

∑

j=1

NIR (2)

In this case, the Eq 1 becomes Eq 2, where the vari-

ables are the same as in Eq 1. If the templates of

the building can be got, the building edited in Fig-

ure 6 can be edited in 34 steps, reduced by 21 percent.

The system requires nearly no professional knowl-

edges, which make it nearly no difference between

experienced and non-experienced users. Five non-

experienced persons are chosen to modify the build-

ing in Figure 6. They spend about ten minutes to be

familiar with the system. Then three different cases

are tested and average time cost for them are shown

in Figure 7.

In case A, all the persons have no available tem-

plates. They have to measure the building compo-

597

0 0

1852

1785

1830

113

0 0

468

453

471

3030

2238

2301

500

1000

1500

2000

2500

3000

3500

A B C

TMC/s

TMB/s

TET/s

TEB/s

TT/s

Case

Figure 7: Time to modify the building. TMC, TMB, TET,

TEB, TT are time to measure the building component, time

to measure the building, time to edit the templates, time to

edit the building and total time for all of the above.

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Table 3: Comparison between different tools.

Tool CPY PR AR MM UBY

Kendzi3D YES JOSM, Kendzi3D plugin, Computers CAD skills NO Medium

OBM NO Professional CAD tool, Computers CAD skills NO Low

Our System YES WebGL browser, Computers or Mobile devices few skills YES High

nents and edit the templates. In case B, all the per-

sons have modiﬁed a similar building and they can

get all the templates from the user based templates of

the system. In case C, the persons get all the templates

from the location based templates of the system.

PercentSaved =

(OriginTime − AvgTime)

OriginTime

∗ 100

(3)

The template management methods can signiﬁcantly

reduce the time to modify the building. We compute

the percentage time saved with Eq 3. OriginTime is

the time cost without any template management (time

cost in case A ). AvgTime is the average time cost

with user based template management and location

based template management ( average time cost of

both case B and case C ). Compared case B and C with

case A, 25.1 percent of time is saved for the users.

In the editing process, about 19.4 percent of time is

saved. At present, most time to modify the building is

taken by measuring the building. The time to edit the

building in our system only takes 19.2 percent of the

whole time. There is a trend that mobile devices are

equipped with more and more measurement sensors.

We believe that time for measurement of the building

will be reduced in the near future. When the measure-

ment is done, the time to modify the building with our

system is only 581 seconds, less than ten minutes.

5.3 Compared with other Related Tools

As Openstreetmap develops very fast, there are sev-

eral tools to modify 3D information for OSM. Here

we will compare our system with another two tools,

Kendzi3D and Open Building Models ( OBM ).

Kendzi3D

has a plugin in the Openstreetmap ed-

itor JOSM. With Kendzi3D plugin, the user can edit

the building model in a 3D environment. Besides,

compared with the traditional editing methods by just

adding key-value pair tags, kendzi3D plugin avoids

the potential modeling errors and ensures the topo-

logical consistency in complex 3D models. In fact,

Kendzi3D is a light weight CAD tool to modify 3D

building models.

Open Building Models (Uden and Zipf, 2013) is

another tool to collect detailed 3D information for

http://wiki.openstreetmap.org/wiki/JOSM/Plugins/

Kendzi3D

Openstreetmap. Exactly, it is an independent project

related to Openstreetmap. In OBM, the user con-

structs a detailed 3D building model with local CAD

tools. Then the user transforms the model into VRML

format. On the website of OBM, the user selects the

building in Openstreetmap and uploads the 3D model.

We evaluate the three tools. The result is shown

in table 3. CPY, PR, AR, MM and UBY are com-

patibility, platform requirement, ability requirement,

management of models and usability of the tool.

For compatibility, the data of our system, together

with Kendzi3D are in xml format, the same as Open-

streetmap data. They can be easily represented and

stored in current OSM database. The data format of

OBM is VRML, a 3D model format. In the OBM sys-

tem, an independent database is created to store the

3D data.

The platform requirement of our system is less

than the other two tools. Kendzi3D requires the

JOSM editor and the Kendzi3D plugin. For OBM,

professional CAD tools are essential. Both of their

requirements can only be met on computers with spe-

cial softwares while our system requires only a We-

bGL supported browser. At present, it can be met by

a variety of popular browsers including IE, Chrome,

Firefox

on not only computers but also mobile de-

vices.

To modify the building, only a few steps are re-

quired in our system. The user can be familiar with

the steps in several minutes while Kendzi3D and

OBM need professional CAD skills. Besides, con-

sidering easing the operations of the user, our sys-

tem implements template management methods. This

is proved to be more efﬁcient in ﬁgure 7. Neither

Kendzi3D nor OBM has this feature. Every time to

modify a new building, they have to build every com-

ponent and make a fresh start.

The usability is a overall evaluation for both PR

and AR in table 3. OBM requires Professional CAD

tool for the platform and CAD skills for the user. The

usability is scored as Low. Kendzi3D requires JOSM,

Kendzi3D plugin for the platform and CAD skills for

the user. Compared with OBM, it is a light weight

CAD tool and easier to use. Its usability is scored as

Medium. Our system requires few professional skills

and the WebGL browser is supported in most plat-

https://en.wikipedia.org/wiki/WebGL

Massive Detailed 3D Geographic Information Collection on the Web

103

forms. The usability is scored as High.

As a conclusion, our system is very competitive

against Kendzi3D and OBM. It is compatible with the

Openstreetmap perfectly. It requires less for the plat-

form and for the user. The existing information and

data of the system are reused to simplify the opera-

tions. The system is of high usability.

6 CONCLUSIONS

The main contribution of this paper is a new sys-

tem for detailed 3D geographic information collection

through VGI. We introduce a template based CAD

methodology to edit the building. The OSM data

are extended to represent and store the template data.

Template management methods are proposed to man-

age and reuse the existing templates. When trans-

formed into OGC standard CityGML format, the col-

lected data can be widely used in a variety of applica-

tions and spatial analysis. With the widely-applicable

feature and no professional knowledge required, the

system extends the collection to mobile devices and

non-professional contributors. Collection for massive

detailed 3D geographic information will be achieved

through a large number of contributors of VGI.

In the future, more base templates will be pro-

posed to edit more complex details. We encourage

volunteers to contribute base templates for the sys-

tem. We will get a more detailed 3D world from VGI.

ACKNOWLEDGEMENTS

Thanks to the OpenStreetMap community for the free

geographic data.

REFERENCES

Arnaud, R. and Barnes, M. C. (2006). COLLADA: sailing

the gulf of 3D digital content creation. CRC Press.

Behr, J., Eschler, P., Jung, Y., and Z

ollner, M. (2009).

X3dom: a dom-based html5/x3d integration model.

In Proceedings of the 14th International Conference

on 3D Web Technology, pages 127–135. ACM.

Behr, J., Jung, Y., Keil, J., Drevensek, T., Zoellner, M., Es-

chler, P., and Fellner, D. (2010). A scalable architec-

ture for the html5/x3d integration model x3dom. In

Proceedings of the 15th International Conference on

Web 3D Technology, pages 185–194. ACM.

Fan, H., Zipf, A., Fu, Q., and Neis, P. (2014). Qual-

ity assessment for building footprints data on open-

streetmap. International Journal of Geographical In-

formation Science, 28(4):700–719.

Goetz, M. (2013). Towards generating highly detailed

3d citygml models from openstreetmap. Interna-

tional Journal of Geographical Information Science,

27(5):845–865.

Goetz, M. and Zipf, A. (2011). Extending OpenStreetMap

to indoor environments: bringing volunteered geo-

graphic information to the next level. CRC Press:

Delft, The Netherlands.

Goodchild, M. F. (2007). Citizens as sensors: the world of

volunteered geography. GeoJournal, 69(4):211–221.

Kolbe, T. H., Gr

oger, G., and Pl

umer, L. (2005). Citygml:

Interoperable access to 3d city models. In Geo-

information for disaster management, pages 883–899.

Springer.

Marrin, C. (2011). Webgl speciﬁcation. Khronos WebGL

Working Group.

Over, M., Schilling, A., Neubauer, S., and Zipf, A. (2010).

Generating web-based 3d city models from open-

streetmap: The current situation in germany. Comput-

ers, Environment and Urban Systems, 34(6):496–507.

Patow, G. (2012). User-friendly graph editing for proce-

dural modeling of buildings. Computer Graphics and

Applications, IEEE, 32(2):66–75.

Schilling, A. and Kolbe, T. H. (2010). Draft for candidate

opengis

 web 3d service interface standard. Version

0.4. 0.

Smelik, R. M., Tutenel, T., Bidarra, R., and Benes, B.

(2014). A survey on procedural modelling for vir-

tual worlds. In Computer Graphics Forum, volume 33,

pages 31–50. Wiley Online Library.

Uden, M. and Zipf, A. (2013). Open building models: to-

wards a platform for crowdsourcing virtual 3d cities.

In Progress and New Trends in 3D Geoinformation

Sciences, pages 299–314. Springer.

Verma, V., Kumar, R., and Hsu, S. (2006). 3d building

detection and modeling from aerial lidar data. In

Computer Vision and Pattern Recognition, 2006 IEEE

Computer Society Conference on, volume 2, pages

2213–2220. IEEE.

Web3DConsortium. X3d speciﬁcation. http://www.web3d.

org/documents/speciﬁcations/19775-1/V3.3/index.

html.

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