能见度不好 meaning in English

visibility poor

The methods for solving these problems are put forword as follows : the method of airphoto scale rangs from 1 / 4 to 1 / 6 of map scale ; a flight line uses belt method ; the optional time intervals of airphoto taking are from may to june and from august to october in one year ; when the contrast at the site is small , or the visibility is rather low and needs to enchance the contrast , the hardening agent should be prepared to process the film
并提出了解决问题的方法：山区航空摄影合理的摄影比例尺应是成图比例尺的1 / 4 ~ 1 / 6 ；对于山区窄而长，且为线状走势的河流宜采用带状航线设计方法设计；山区流域水分充足能见度不好，惟每年5 - 6月和8 - 10月是航空摄影的最佳季节；当地面物体反差小或能见度不好而需要特别提高反差时应配制较硬性药水冲洗等。