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2 American Society of Photogrammetry. 51 st Annual Meeting, March Washington. Vol. 1. p , 1985 SURVEYING AND AUTOMATIC MAPPING OF SAO PAULO STATE, BRAZIL: A GEOGRAPHIC INFORMATION SYSTEM WITH EMPHASIS ON LAND USE R. Serra Filho A. C. Cavalli TerraFoto S/A Atividades de Aerolevantamentos Rua Nova York, 833, Brooklin, S. Paulo, SP - Brasil H. S. Pinto Universidade Estadual de Campinas IB/CEPAGRI/UNICAMP. P. O. BOX , Campinas, SP - Brasil ABSTRACT The Sate of S. Paulo is a region with some 250,000 km 2 situated in the southeastern Brazil. As a tropical area it shows extreme variation in geographical information, providing government and private companies with a large amount of data which, despite being available, are not organized or standardized in the greatest part of the existing files. As an attempt for the development of applied projects in areas of Land Use Monitoring, Production Forecast, and Field Surveys, etc., a system called State System for Geographical Information" is being developed, to concentrate all kinds of geographical data in a data bank of an INTERGRAPH System. The basic information will be recorded as a grid of 1,000,000 points, referred to UTM coordinates, each one being an address for up to 63 levels of data attributes. It is supposed that the ability of the computer for transferring information from a grid to polygon basis and vice-versa, allied to a sampling model to be used in the field, will result in a fast and cost effective system with very low index of error. Key words: land use, photointerpretation, sampling grid, geographic information system. INTRODUCTION The State of Sao Paulo occupies an area of about 250,000 km 2 in the South of Brazil, between latitudes 20 and 25 S. The tropical characteristics of this region, its diversified climate, provide means for cultivation of a wide range of crops and plants as different as equatorial and temperate ones. The several types of soils existent in the region, together with the diversified climate provide for a very rich vegetal overgrow. This peculiar localization and also the fact that the State of Sao Paulo detains the greatest degree of development of the country, is responsible for the great amount of agricultural, industrial, geological and socio-economical information available, either in government or private institutions. Nevertheless, data acquired by different institutions, using different methods, yield results which are not compatible. On the other hand, geographic information acquired by conventional survey methods, is usually published in different times, presented under different scales and projections, or are too specific and sectorial, or too generic and comprising. Further, the great time lapses between the acquisition of data and the effective publication, contributes to obsolescence. This is very much the truth for information on land use for agrarian projects. The basic aim of the proposed System is the development of a Data Bank with standardized and up-to-date geographic information, to be displayed by means of maps, graphics and /or tables. The possibility of interaction among such information will allow the elaboration of cross-analysis of most suitable conditions for some agrarian, cattle-raising and industrial activities, as well as the elaboration of social and economical development projects. The System will present the following basic characteristics: - High versatility to process information from the greatest number of data generation sources; - High processing speed, to become an effective help for decision-makers, either in private or government institutions; - Availability for periodical updating; - Availability for compatibilization of information in different degrees and scales. OBJECTIVES The main objectives of the System are: To provide required geographical information in association with data of different types such as vegetation, soil, climate, hydrology, etc; To develop photointerpretation techniques, to feed the System with data acquired from aerial photographs or

3 any other kind of remote sensing equipment, thus providing for periodic updating information on land use; To subsidize forecast of agricultural production programs, by means of statistical sampling, taking into account the climatic diversity; To help establishing economical regional capacity based on agrarian activities, by means of maps; To provide information for government programs on soil, irrigation, drainage and conservation; To monitor land use State wide. METHODOLOGY The Graphic Interactive System The System is based on Intergraph equipment consisting of a VAX 11/730 computer, a graphic station, an Intermap module to be coupled to stereo plotters and peripherals such as plotters, digitizers, CRT's and printers. The System will be run on a permanent geographic basis composed of a grid of sampling points, spatially distributed in such a way as to allow statistical analysis. Selected information will be associated to each one of these grid points (1,000,000 total), so as to obtain a configuration of the type "address/attribute", which will provide for maps containing crossed and overlapping information. The "point addresses" will be referred to UTM coordinates displayed in topographic maps covering the whole State. The System will allow the interaction between grid and polygon files, thus enabling the overlaying of maps. The Grid of Sampling Points The survey of land use by direct boundary delimitation of category is a high cost and very slow activity specially when performed over a vast territorial extension comprising various types of land use. This is a serious handicap for an information system based on features such as precision, velocity and low cost. Some characteristics of the project such as: - The vast territorial extension to be surveyed; - The different categories of land use to be mapped; - The need of results at a short time; - The limited number of technical personnel, as well as the kind of basic information on each category of land use to be fed into the system (occupied area and spatial distribution), were taken into account in order to choose the method of mapping by systematic sampling rather than direct boundary delimitation. Planimetry by systematic sampling uses a grid of points to measure areas which compare best with other conventional planimetric methods on such features as precision and operational yield for small areas with intense occurrence. The method also allows the determination of relative errors. The number of sampling points required is calculated through the equation (Eq. 1): N = Total number of points for sampling; P = Percentage ratio of occupied area by category of land use to be surveyed and area of region surveyed; E = Relative sampling error, expressed as percentage of P; = Numerical factor which corresponding to the determination of results with a 95% probability of being contained within the Interval of confidence. Both horizontal and vertical distances between the points in the System are 500 m. Thus, approximately 1,000,000 points will be required to cover the whole area of the State of Sao Paulo. In practice, this means that even categories of land use which occur only over 1% of the whole area of the State can be measured with a relative error of 2%. The precision attained will yield very good results either for regional or municipal level. Incorporation of Existent Data The development of the graphic system of geographic information will be based mainly on the use of thematic maps which have already been compiled and published by government institutions. These maps cover a wide range of themes such as land use, climate, vegetation, agricultural aptitude and also present statistical data referred to municipal districts or administrative and geographic regions. However, the cartographic basis on which they have been compiled is not always compatible with the structure of the proposed System, and information presented on different quantitative and qualitative levels. This wide range of maps and data will undergo detailed analysis and only those which display

4 important features will be picked up to be digitalized and incorporated to the Data Bank. Data Acquisition by Photointerpretation Data acquisition on territorial occupation will be performed by means of recent aerial photographs. However, the recent data available from aerial survey of the State does not provide complete knowledge in land use due to have being performed in different periods of time, and over different areas. Thus, the first phase of the project will consider only the Administrative Region of Ribeirao Preto, an area of about 36,000 km which has undergone recent aerial survey. As soon as new aerial surveys are performed over other Regions, photointerpretation services will follow and the System will be fed with up-to-date information. Photointerpretation will be performed according to the method of systematic sampling by grid of points. The points will be transferred from the UTM grid to the aerial photographs and photointerpreted. The category of land use thus determined will be referred to this point, which will become a permanent geographic address. Every and ulterior information will then be referred to this address, enabling whenever new data is acquired either by more recent aerial surveys or by satellite images from LANDSAT 5 and SPOT. Operation of the System The System will be operated as shown in figure 1. Figure 1. The operation of the interactive system for data acquisition. During the initial phase - data entry - geographical information acquired from land use survey, by means of photointerpretation or field survey; information acquired by any other existent geographic surveys (soil, climate, geology, geomorphology, erosion, infrastructure, declivity, etc); non-geographic information (population, production, yield, etc), will be digitalized through the digitizing table of the graphic interactive system, thus developing the Data Bank. The integration of such different data sources can be accomplished through extensive coordinate transformation procedures. These include surveying adjustment, transformation of surface planes, ellipsoidal projections and stereographic models. The merging of data produces a single basis for integrated mapping with separated functions. These functions, however, can be coordinated to provide for dynamic dealing of graphic and non-graphic information. Due to the possibility of selective retrieval and transformation of important information, the elements required for decision-making over manipulation of spatial relations inherent to the system, such as overlapping polygon maps versus grid point maps, will be easily accessed. The results will then be displayed on the digitizing tables through high resolution plotters, maps, printers or color CRT's. Pilot Project An example of information retrieval is shown in figures 2, 3 and 4. Figure 2 shows the isolines of annual mean temperatures in the State of Sao Paulo and figure 3 the annual water deficiencies according to Thornthwaite and Mather method Figure 4, resulting from the association of the former two, shows the climatic aptitude of sugar-cane in the State of Sao Paulo, based on those two fundamental climatic elements for sugar-cane cultivation.

5 Figure 2. Isolines of annual mean temperature in the State of São Paulo (Instituto Agronômico de Campinas, 1974) Figure 3. Isolines of annual water deficiencies according to Thornthwaite & Mather 1955 (Instituto Agronômico de Campinas, 1974) Figure 4. Climatic aptitude of sugarcane in the State of São Paulo (Instituto Agronômico de Campinas, 1974)

6 Further on, the project will determine pedologic aptitude which can be obtained from the survey on classes and capacities of land use in the State of Sao Paulo. Climatic and pedologic aptitude thematic maps will then be combined to yield the ecological thematic map for sugarcane. Current Stage of the Project The development of agricultural activities in Brazil, and especially in the State of Sao Paulo, has occurred in cycles of different intensities and extensions. The first great coffee cycle stablished agrarian borderlines in the State, which have remained more or less the same. By some recent cultivation of poorer soils, such as the "cerrado" (a type of savannah), these borderlines have been added with different crops or even more coffee. Those vast borderlines, established on the richest soils of the State, resulted in a high degree of crop rotation. Recently, agricultural characteristics in the State of Sao Paulo have been modified by two important facts: the drastic reduction of coffee cultivated area and its transposition to the "cerrado" soils, and the enormous increase of sugarcane cultivated areas, due to PROALCOOL (A Government Program for the Production of Carbureting Alcohol). The expansion of sugarcane cultivated area has pushed other economically important cultures out of the richer soils. The project is analyzing the consequences of this expansion at first for the Administrative Region of Ribeirao Preto (Fig. 5), where the concentration of sugarcane culture is of some 650,000 ha, one of the greatest continuous cultivated area in the world. The impact of such a concentration will be quantified when its real geographic boundaries have been determined. The method of analysis proposed is the comparative study of "time patterns" resulting from aerial surveys performed over the Region in 1962, 1972 and Figure 5. The State of São Paulo with its administrative regions Data on substitution, increase and development of different categories of land use will be determined and quantified with special emphasis on the behavior of sugarcane cultivation, which rose from 145,000 to 650,000 ha in a boom started in 1975/76 with the Proalcool Program. Data obtained in the aerial survey performed in 1972 will be an excellent reference for this boom. The use of information on climatic aptitude as well as the surveys on soils and classes of capacities of land use will help establishing reformulation policy over land use in the Region, so that good balance between the cultivation of energetic and provision crops will be accomplished. FINAL COMMENTS The first phase of the project will be running fully at the end of the first semester of 1985, and the whole system at the beginning of Further amplification of existent hardware will be required to accommodate the great amount of data acquired during the development of the project The substitution of the existent CPU for a model VAX 8600, the amplification of disk capacity, and the purchase of other graphic working stations and plotters has already been thought of.

7 REFERENCES Center for Advanced Computation, 1972, Illinois Resource Information System, Feasibility study, 204 p. Urbana-Champaign, University of Illinois. Chiarini, J.V., et al Uso do solo no Estado de Sião Paulo. Bragantia, Vol 37, pp , Campinas-SP. Brasil. et al , Uso atual das terras do Estado de São Paulo.: Boletim Técnico Instituto Agronômico, Vol. 37, pp. I- 36. Campinas-SP, Brasil Cochran, W.G., 1977, Sampling Techniques, pp , New York,.la Wiley & Sons. Dmitriev, Y.G., Determining the percentage of different area on soil maps and certain other maps: Soviet Soil Science, Vol.2, pp , Moscow. Kofler, N.F., Cavalli, A.C.; Chiarini, J.V. and Nogueira, F.L Inventario Canavieiro com auxilio de fotografias aéreas. A grande região de Piracicaba no ano-safra 1978/79: Boletim Técnico Planalsucar. Vol. 1, pp. 3-38, Piracicaba, Instituto do Açúcar e do Álcool., 1980, Inventario Canavieiro com auxilio de fotos aéreas. A grande região de Jau no ano-safra 1979/80: Boletim Técnico Planalsucar, Vol. 2, pp. 1-22, Piracicaba, Instituto do Açúcar e do Álcool. São Paulo - Secretaria da Agricultura, 1974, Zoneamento Agrícola do Estado de São Paulo, Vol. 1, pp , São Paulo, CATI. Serra Filho, R.; Cavalli, A.C.; Guillaumon, J.R., 1975, Levantamento da cobertura vegetal natural e do reflorestamento no Estado de São Paulo: Boletim Técnico Instituto Florestal, Vol. 11, pp. 1-53, São Paulo, Instituto Florestal. São Paulo. Secretaria da Agricultura, 1976, Programa de proteção da bacia ecológica do rio Mogi Guaçu. Anteprojeto preliminar, pp. 2-São Paulo, CPRN.