determining the qualification of aerial photos for classification of urban forests case study in zone six of tehran

green space is counted as one of the important bases of each city, especially great cities like tehran. with considering to vast application of urban green aria, the necessity of the managing these sources is felt more day-by-day. for proper managing each source, first the inventory of that source is taken into the consideration. regretfully so far there has been no comprehensive studios pattern for studying the situation of urban forests and urban green area.in this study, by using of describing aerial photos as numerical, the urban green aria has been classified. after performed survays, it was certified that classification on numerical ortho photo mosaics is easier and more precise, comparing with manual description, and consequently this method was used. the method was in a way that at the first step, 23 pieces of aerial photos 1:800 and 1:10000 of year 1381 in district 6 of tehran were orthofied by using pci geomatica software and then a mosaic of orthofied photos was prepared. in the next step, classifying on 5 classes was done on numerical ortho photo mosaic and the map was prepared because of this classification by using arc gis software. in addition, the surface and the length of the levels were calculated. these levels were as urban park in scale of fore arial and arial, urban park in scale of locality, tree complexes, linear trees and scattered trees.for calculating cover crown, dotted net with the distances of 1 millimeter (as numerical layer) was used and for creating a relationship between this element(cover crown), separately collecting statistics on the photo and in the field, sampling with the sample parts having a fixed surface (7 ares) and 5-trees-transects were done.