This paper aims to argue three themes on the extended representation for geographic information. The first theme argues the extended type of General Portrayal Model (GPM), by which more various geographic information representations such as an interactive map, a feature index, and a list of geographic information become realizable. The second theme argues that the designation of a proxy attribute as a substitution of geographic feature is effective to raise the consistency of the geographic data as the set of features and the geographical information as the representation. The third theme argues that the learning support software tool of geographical information technology called “gittok” can realize various information representations by implementations of the GPM and the proxy attribute.

There are at least two types of features. One is a feature with a spatial attribute, and another is a feature without a spatial attribute. For example, premises such as a campus associating with a university includes grounds and buildings. Actually, grounds and buildings have spatial attributes describing their shapes and positions, as they are physical features. However, a university itself does not have a spatial attribute, because it is a virtual feature. It means that a university exists in the real world as an agreement by involved parties and people. Thus, features with and without spatial attributes may be mixed in a geographic dataset. GPM proposed in this paper enables to model schemata for the representation of maps to represent physical features as maps, and to represent virtual features as lists.

Proxy attribute and GPM were implemented in gittok to prove the hypothesis declared above. Students can practice mapping and listing through application schema designing, data acquisition by digitizing, portrayal and/or list schema designing, and map and/or list editing. Such exercises can support students to understand the images of cartography and geospatial information technology.

Tsunamis brought by large earthquakes and floods brought by heavy rainfalls suffer us for long years. Recent disasters like tsunami caused by the 2011 off the Pacific coast of Tohoku Earthquake and flood by heavy rainfall in Sep. 2015 still remain on our memory as many lives were lost.

Although detection of flooded area is relatively easy to grasp through aerial photographs, other optical or radar observations, investigation of flooded depth in large area is very difficult because the data are basically collected by on-site surveys and those surveys require a lot of time.

On-site surveys of tsunami flooded depth are basically operated by surveying tsunami marks on buildings walls or trees. Tsunami marks are remained by muddy water or floating matter. For instance, tsunami marks by muddy water can be observed like horizontal lines. Also, tsunami marks by floating matter can be observed as damages on buildings. Flooded depth mapping can be easily done if information of those marks can be collected more speedy and more effectively.

Geospatial Information Authority of Japan (GSI) recorded tsunami damage images of the 2011 off the Pacific coast of Tohoku Earthquake. We tried tsunami flooded depth measurement from the Mobile Mapping System (MMS) images in order to hand down to posterity by using MMS for mapping of tsunami flooded depth widely on the 2011 off the Pacific coast of Tohoku Earthquake. MMS was expected to be able to collect a lot of tsunami mark images for a short time.

MMS images through Sendai plain to Ishinomaki plain were taken in April 2011, and Southern Sanriku area to Northern Sanriku area were taken in May 2011. In other words, the images were collected for one or two months after the earthquake. Tsunami flooded depth data were collected at 873 points through MMS image analysis, and flooded depth at 77 points measured by MMS could be identified on-site. On-site surveys were conducted in 2011 to 2013.

Results are as follows:

1) By mapping of tsunami flooded depth data in a wide area, overview of distribution of tsunami flooded depth can be grasped, and mapping result might be used for evaluation of geomorphological effect for variation of tsunami flooded depth.

2) Tsunami flooded depths measured from MMS images correspond well with on-site survey. 88% of flooded depth measurement points which were both analyzed by MMS images and surveyed on-site, supposed to measure the same tsunami flooded marks.

3) Tsunami flooded depth measurement from MMS image is very useful way for collecting flooded depth data as the measurement is very accurate and a lot of marks of tsunami flood can be collected speedy and effectively.

MMS image analysis for flooded depth measurement might be effective not only for tsunami, but also for heavy rainfall. If more dense data can be collected by MMS image, contours of flooded depth can be drawn more correctly and precisely. Accumulation of studies on flooded depth might contribute to reveal mechanisms of flood occurrence.

Notice: This report is made from authors' individual experiences on geographic and cartographic studies, and the report doesn't mean MEXT's (Ministry of Education, Culture, Sports, Science and Technology's) official positions.