Datafile segment space map

Summary 
How the segments are stored on the datafile blocks.

SELECT start_block, end_block, 
ROUND(((end_block-start_block) * (SELECT VALUE FROM v$parameter WHERE NAME = 'db_block_size'))/(1024*1024),2) MB_SIZE, 
owner, segment_name, partition_name, segment_type 
FROM (SELECT file_id, block_id START_BLOCK, block_id + blocks - 1 end_block, owner, segment_name, partition_name, segment_type 
FROM dba_extents 
WHERE tablespace_name = '&tablespace'  
"UNION ALL" SELECT file_id, block_id, block_id + blocks - 1   end_block, 
'free' owner, NULL segment_name, NULL partition_name, NULL segment_type
FROM dba_free_space 
WHERE tablespace_name = '&&tablespace'
ORDER BY 1,2)
WHERE file_id = &datafid
ORDER BY end_block DESC;

START_BLOCK  END_BLOCK    MB_SIZE OWNER           SEGMENT_NAME                   SEGMENT_TYPE
----------- ---------- ---------- --------------- ------------------------------ ---------------
    1682036    1682047        ,34 free
    1682034    1682035        ,03 PRESENT_PERIF   WORK_HOURS_FCT                 TABLE PARTITION
    1603008    1682033    2469,53 free
    1602976    1603007        ,97 PRESENT_PERIF   KPI_QUALLL_TMP                 TABLE
    1560608    1602975    1323,97 free
    1228576    1560607   10375,97 free
    1228544    1228575        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227776    1228543      23,97 free
    1227744    1227775        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227712    1227743        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227680    1227711        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227648    1227679        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227616    1227647        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227584    1227615        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227552    1227583        ,97 PRESENT_PERIF   ACTIVE_PRODUCT_FCT_MON_SNP     TABLE PARTITION
    1227520    1227551        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216512    1227519     343,97 free
    1216480    1216511        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216448    1216479        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216416    1216447        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216384    1216415        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216352    1216383        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216320    1216351        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216288    1216319        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1216256    1216287        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1214208    1216255      63,97 free
    1214176    1214207        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1214144    1214175        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
    1214112    1214143        ,97 PRESENT_PERIF   KPIEETT_MONTHLY_AGG            TABLE PARTITION
.......
.......
.......

Tip: If i move table PRESENT_PERIF.WORK_HOURS_FCT and table PRESENT_PERIF.KPI_QUALLL_TMP then i can resize the datafile to save 0,34 + 2469,53 = 2470MBytes from filesystem