Vehicle classification is a hot computer vision topic, with studies ranging from ground-view to top-view imagery. Topview images allow understanding city patterns, traffic management, among others. However, there are some difficulties for pixel-wise classification: (a) most vehicle classification studies use object detection methods, and most publicly available datasets are designed for this task, (b) creating instance segmentation datasets is laborious, and (c) traditional instance segmentation methods underperform on this task since the objects are small. Thus, the present research objectives are: (1) propose a novel semi-supervised iterative learning approach using GIS software, (2) propose a box-free instance segmentation approach, and (3) provide a city-scale vehicle dataset. The iterative learning procedure considered: (1) labeling a few vehicles from the entire scene, (2) choosing training samples near those areas, ( 3) training the DL model (U-net with Efficient-net-B7 backbone), (4) classifying the whole scene, (5) converting the predictions into shapefile, (6) correcting areas with wrong predictions, (7) including them in the training data, (8) repeating until results are satisfactory. We considered vehicle interior and borders to separate instances using a semantic segmentation model. When removing the borders, the vehicle interior becomes isolated, allowing for unique object identification. Our procedure is very efficient and accurate for generating data iteratively, which resulted in 122,567 mapped vehicles. Metrics-wise, our method presented higher IoU when compared to box-based methods (82% against 72%), and per-object metrics surpassed 90% for precision and recall.